,,non-,,technical ,,chats ,,on ,,iron ,,and ,,steel ,,and ,,their ,,application ,,to ,,modern ,,industry ,,by ,,la ,,verne ,w4 ,,spring1 ,a4,b4 ,,chief ,,chemist ,,and ,,metallurgist1 ,,crane ,,co41 ,,chicago ,,with ,,two ,,hundred ,,and ,,ninety-,,four ,,illustrations ,,and ,,diagrams ,illustration3 ,logo ,,new ,,york ,,frederick ,a4 ,,stokes ,,company ,,publishers ,copyright1 #aiag1 by ,,frederick ,a4 ,,stokes ,,company ,all rights reserved1 including that of translation into foreign languages ,,to ,,my ,,fellow ,,workers ,,in ,,the ,,vast ,,iron ,,and ,,steel ,,industry ,,this ,,book ,,is ,,affectionately ,,dedicated ,,foreword ,it has long been a desire of the author to put into non-technical form the interesting data here given4 ,during several years spent in the service of one of the great steel companies of this country1 first in the laboratories and afterward in the rolling mills1 he acquired a love for the industry that is now of fairly long standing4 ,spending as much of his spare time then and since in visiting various parts of that mammoth plant and as many others as he was able1 he has always felt that this extremely interesting subject could not fail to prove fascinating even to those who had previously known little of the manufacture of steel and steel products4 ,later work with gray and malleable cast irons and with cast steel enlarged the outlook and further urged his sharing these interesting things with others not so fortunately situated4 ,such an inspiration1 if it may so be called1 is the reason for the appearance of these articles4 ,practically as here reprinted1 the first thirteen of them were published during #aiae and #aiaf in serial form in the 8,valve ,world10 the house organ of ,crane ,company of ,chicago1 with which the writer for some time has been connected4 ,the enthusiasm with which they were received has been very gratifying1 while the scores of letters bearing favorable comment testify to the correctness of the judgment that the metallurgy of our most useful metal1 iron1 is of very general interest4 ,it may be remarked by some that certain of the statements made in the book are not strictly accurate in that few details have been stated or exceptions made4 ,this is true1 but it seemed necessary if main facts were to be made to stand forth with the boldness required to accomplish the purpose which the author had in mind4 ,the chapters are in no way intended to be an encyclopedia of the subject4 ,the idea throughout has been to present only the main points and to show the derivation of the products from the raw materials and their relationships to each other4 ,in other words the book is intended only as a sort of outline4 ,references are given which will aid in the selection of works to be consulted by any who are sufficiently interested to go farther4 ,without the encouragement and coperation of ,crane ,company and the kind assistance of friends1 some within and some without the iron and steel industry1 this little book would not have been possible4 ,special mention must be made of the aid given by ,messrs4 ,i4 ,m4 ,bregowsky1 ,j4 ,a4 ,matthews1 ,c4 ,d4 ,carpenter1 and others whose reading of and suggestions concerning parts of the manuscript were of much help4 ,thanks are due also to many individuals and firms for their very hearty coperation in furnishing information and the photographs which appear in the pages of the book4 ,l4 ,w4 ,s4 ,illustrations are from the following sources3 ,a4 ,m4 ,byers ,co41 ,pittsburg4--,national ,tube ,co41 ,pittsburg4--,u4 ,s4 ,steel ,corporation1 ,new ,york4--,tennessee ,coal1 ,iron ,railroad ,co41 ,birmingham1 ,ala4--,shenango ,furnace ,co41 ,pittsburg4--,pickands1 ,mather ,co41 ,pittsburg4--,united ,states ,geological ,survey4--,wellman-,seaver-,morgan ,co41 ,cleveland1 ,o4--,lackawanna ,steel ,co41 ,buffalo4--,cleveland-,cliffs ,iron ,co41 ,ishpeming1 ,mich4--,j4 ,h4 ,hillman ,sons ,co41 ,pittsburg4--,harbison-,walker ,refractories ,co41 ,pittsburg4--,by-,products ,coke ,corporation1 ,chicago4--,h4 ,koppers ,co41 ,pittsburg4--,federal ,furnace ,co41 ,chicago4--,crucible ,steel ,company of ,america1 ,pittsburg4--,crane ,co41 ,chicago4--,interstate ,iron ,steel ,co41 ,chicago4--,la,belle ,iron ,works1 ,steubenville1 ,o4--,morgan ,construction ,company1 ,worcester1 ,mass4--,j4 ,a4 ,matthews4 ,syracuse1 ,n4 ,y4--,mc,lain's ,system1 ,milwaukee1 ,wis4--,allis-,chalmers ,co41 ,milwaukee1 ,wis4--,j4 ,h4 ,williams ,co41 ,new ,york4--,griffin ,wheel ,co41 ,chicago4--,u4 ,s4 ,molding ,machine ,co41 ,cleveland4--,bradley ,manufacturing ,co41 ,bradley1 ,ill4 7,sears1 ,roebuck ,co41 ,chicago74--,snyder ,electric ,furnace ,co41 ,chicago4--,commonwealth ,steel ,co41 ,st4 ,louis4--,john ,a4 ,crowley ,co41 ,detroit4--,illinois ,steel ,co41 ,chicago4--,pickands1 ,brown ,co41 ,chicago4--8,sketches of ,creation10 by ,alexander ,winchell4 ,harper ,bros41 ,new ,york4--8,descriptive ,metallurgy of ,iron10 by ,s4 ,groves4--8,materials of ,engineering10 by ,r4 ,h4 ,thurston4 ,john ,wiley ,sons1 ,new ,york4--8,chambers' ,encyclopedia40 ,j4 ,b4 ,lippincott1 ,philadelphia4--8,cast ,iron in the ,light of ,recent ,research10 by ,w4 ,h4 ,hatfield4 ,charles ,griffin ,co41 ,ltd41 ,london4--8,handbook of ,chemical ,technology10 ,wagner-,crookes4 ,d4 ,appleton ,co41 ,new ,york4--8,the ,ore ,deposits of the ,united ,states and ,canada10 by ,j4 ,f4 ,kemp4 ,mc,graw-,hill ,book ,co41 ,new ,york4--8,the ,valve ,world40 ,crane ,co41 ,chicago4--8,the ,romance of ,steel10 by ,h4 ,casson4 ,a4 ,s4 ,barnes ,co41 ,new ,york4--8,the ,metallurgy of ,steel10 by ,harbord ,hall4 ,chas4 ,griffin ,co41 ,ltd41 ,london4--8,metallurgy of ,steel10 by ,h4 ,m4 ,howe4 ,mc,graw-,hill ,book ,co41 ,new ,york4--,tomlinson's 8,encyclopedia of ,useful ,arts0 7#ahed74 ,g4 ,virtue ,co41 ,new ,york4--8,liquid ,steel10 by ,e4 ,g4 ,carnegie4 ,longmans1 ,green ,co41 ,new ,york4--8,iron and ,steel in ,all ,ages10 by ,james ,swank4 ,american ,iron ,steel ,association1 ,philadelphia4--8,the ,a4,b4,c4 of ,iron and ,steel40 ,penton ,publishing ,co41 ,cleveland1 ,o4--8,the ,iron ,age40 ,david ,williams1 ,new ,york4--8,the ,iron ,trade ,review40 ,penton ,publishing ,co41 ,cleveland1 ,o4--8,high ,speed ,steel10 by ,o4 ,becker4 ,mc,graw-,hill ,book ,co41 ,new ,york4 ,illustration3 ,,contents ,,chapter ,,page ,i ,,the ,,early ,,history ,,of ,,iron #a ,,ii ,,the ,,raw ,,materials #ag ,,iii ,,raw ,,materials 7,continued7 #cg ,,iv ,,the ,,blast ,,furnace #eb ,v ,a ,,general ,,glimpse ,,ahead #fi ,,vi ,,wrought ,,iron #ia ,,vii ,,cementation ,,and ,,crucible ,,steels #ajf ,,viii ,,bessemer ,,steel #abc ,,ix ,,the ,,open-,,hearth ,,process #adb ,x ,,cast ,,iron #afj ,,xi ,,cast ,,iron 7,continued7 #agh ,,xii ,,malleable ,,cast ,,iron #aie ,,xiii ,,cast ,,steel #bad ,,xiv ,,the ,,alloy ,,steels #bcc ,,xv ,,the ,,high-,,speed ,,steels #bdj ,,xvi ,,the ,,mechanical ,,treatment ,,of ,,steel #bde ,,xvii ,,the ,,rolling ,,process #bei ,,xviii ,,the ,,rolling ,,of ,,rods #bgg ,,xix ,,wire ,,and ,,wire ,,drawing #bhd ,,xx ,,the ,,manufacture ,,of ,,pipe ,,and ,,tubes #bib ,,xxi ,,the ,,manufacture ,,of ,,seamless ,,steel ,,tubes #cjb ,,xxii ,,transformations ,,and ,,structures ,,of ,,the ,,steels #caj ,,xxiii ,,the ,,equilibrium ,,diagram ,,of ,,the ,,iron-,,carbon ,,alloys #cce ,,references #cej ,,index #cee ,,non-,,technical ,,chats ,,on ,,iron ,,and ,,steel ,,chapter ,i ,,the ,,early ,,history ,,of ,,iron ,illustration3 ,,prehistoric ,,man ,when in imagination we see the iron maker of early days sitting cross-legged on his platform between two crude bellows formed from goat skins with slits for air intakes and nozzles of bamboo1 working them alternately to deliver their pitifully small streams of air into the hole in the side of a bank of clay which served as a furnace1 we wonder at his patience2 and after long hours of such effort his reward was only a few pounds of iron6 ,contrast with this1 if you please1 the modern blast furnace with its towering height of #ajj feet1 its four huge heating stoves1 the big blowing engines which each minute deliver to the furnace #ej1jjj cubic feet of blast1 and the whole array of dust arresters1 gas washers1 and automatic ore and coke handling machinery which are essentials of this king of modern metallurgical devices4 ,how insignificant seems the output of the ancient furnace when compared with the daily yield of #ejj tons from this giant of to-day6 ,how has this come about8 ,illustration3 ,,the ,,first ,,razor ,looking back over the centuries we see a period many thousands of years ago when primitive man lived in caves or other rude habitations and was entirely without the implements which we now consider indispensable4 ,the weapons with which he defended his wife and babes from the wild beasts and from his warlike neighbors were clubs1 wooden spears with perhaps a bone or shell tip1 and hatchets of chipped stone tied with thongs of hide into a split stick4 ,he managed by ingenious snares and his crude weapons to provide game and fish for the support of his family4 ,he did not shave often1 for his wife was not as particular in regard to his appearance as are modern women1 but when such a thing happened1 a piece of shell was his razor4 ,the good wife had no steel needles with which to sew together skins for their crude clothing4 ,if she darned her husband's socks it is not recorded1 nor did she use steel crochet hooks in making the 8doilies0 for their parlor table4 ,when grain began to supplement the wild game1 fruit1 and berry diet1 it was broken between flat stones or ground in stone mortars4 ,fires were kindled after long and laborious twirling or rubbing together of two dry pieces of wood4 ,with his stone hatchets and by liberal burning away of parts by fire he formed his canoes from trunks of fallen trees4 ,this was the 8,stone ,age10 and iron and steel were unknown and not to be heard of for many thousands of years4 ,in various parts of the world copper always has occurred 8native02 i4e41 in the metallic form and not in combination with other elements as an earth or ore4 ,as the centuries rolled on1 man eventually learned that this soft red metal could be pounded into thin-edged implements and that it made more useful tools than those of stone1 which his ancestors had taught him to form4 ,some of these metal implements were hard and had fairly good cutting edges1 made so by accidental or intentional presence of tin1 and little did he dream that the twentieth century upon finding his buried bronze implements would think his crude alloy so wonderful and talk reverently of a 8lost art of tempering copper40 ,illustration3 ,,implements ,,of ,,the ,,stone ,,age ,gold1 too1 became known to him because it also occurs 8native40 ,its melting point was low enough that he could fashion it into ornaments1 idols1 and other articles for religious purposes4 ,but during the hundreds of centuries of the 8,stone ,age0 and during much of this--the 8,bronze ,age0--copper1 bronze1 and gold were the only metals used4 ,though the smiths became very dextrous in casting and modeling these metals1 they yet knew not iron or steel4 ,illustration3 ,,implements ,,of ,,the ,,bronze ,,age ,round about them during these many centuries1 as multi-colored earths or rocks1 were the ores of various metals4 ,they little dreamed that when rightly treated certain of the heavy red1 yellow1 or black earths which lay right at their doors could give up that most useful metal1 iron4 ,no one even had knowledge of such a substance1 for1 unlike copper and gold1 iron never occurs 8free10 having too great a tendency to chemically combine with other elements1 for example1 oxygen of the air1 with which1 in moist climates1 it so readily forms 8iron rust40 ,besides1 its melting point is high and so much heat and carbon are needed for its 8reduction0 from the ore that1 during the thousands of years that had gone before1 it had never been produced4 ,illustration3 ,,primitive ,,furnace ,,for ,,smelting ,,iron ,but one day by accident and under fortunate coincidence of rich ore1 high heat1 and plenty of carbon in the form of charcoal from the wood1 a lump of metallic iron was formed underneath a pile of logs which had got afire and burned fiercely because of a high wind4 ,when pounded between two stones this new heavy metal1 too1 was malleable and could be formed into a spearhead superior to anything yet known4 ,every one was interested and an observant one soon 8doped out0 that certain earths could be made to yield this new metal1 iron4 ,the art of extracting it spread slowly1 each artisan learning from his neighbor1 and1 as rich ores were plentiful in many districts1 iron became more and more generally produced4 ,not only in one country was this so but evidence shows that in many others--in ,egypt1 ,chaldea1 ,borneo1 ,india1 ,china1 etc41--roughly similar processes and crude furnaces came to be used4 ,tubal-,cain1 supposedly about #djjj years ,b4,c41 is mentioned in the ,bible as an 8artificer in iron and brass10 and a wedge of wrought iron was buried in the great pyramid of ,cheops probably as early as #cejj ,b4,c4 ,this wedge was recently found and is now the property of the ,british ,museum4 ,the ,chinese made use of iron many centuries before the ,christian era1 but the ,assyrians are supposed to have been the first to use the metal on a really extensive scale4 ,illustration3 ,,the ,,pillar ,,at ,,delhi1 ,,india ,the much discussed pillar at ,delhi1 ,india1 which is still standing in a remarkable state of preservation1 is twenty-two feet high4 ,it is made up of several wrought iron sections cleverly welded together4 ,as the natives regard it with religious awe1 metallurgists have been unable to make thorough investigation and chemical analysis4 ,while the date of its erection is somewhat in doubt1 it is supposed to have been about the #dth or #eth century ,a4,d4 ,but from our modern viewpoint those early iron furnaces were queer things4 ,the first were little more than piles of ore and wood or charcoal on the tops of hills where a brisk wind would make a hot fire4 ,later1 with the invention of the crudest of bellows1 the smelting was done in small holes in the side of banks of clay1 charcoal made from the forest trees being used as fuel4 ,indeed1 some of these types of furnaces still exist and are so operated to-day in neglected districts in ,western ,india and elsewhere1 producing their little five to #ajj pound balls of iron after several hours of tedious work4 ,when the ,romans invaded ,britain 7now ,england71 they found the ,britons making iron in crude furnaces called bloomaries2 and not a great deal of improvement1 except in size1 was made up to ,queen ,elizabeth's time1 when strict laws had to be enacted to prevent destruction of the forests which were being denuded for production of charcoal1 coke1 which we know so well1 not yet having been produced for fuel4 ,illustration3 ,,milady',s ,,needle ,illustration3 ,,the ,,catalan ,,forge ,but the real forerunner of our modern blast furnace was the ,catalan forge1 developed in and named from ,catalonia1 north ,spain1 where it originated4 ,the ,catalan1 however1 and all of such crude early furnaces1 including those thus far described1 produced a variable kind of what we now know as 8wrought iron10 and our modern 8cast0 iron did not appear until about #acej when1 with larger furnaces1 an excess of charcoal1 with greater heat and other favorable conditions1 the ,germans found that the pasty1 difficultly melting metal could be made to absorb carbon enough to make it easily fusible4 ,this was the secret4 ,to state the matter in a simple way1 iron ore1 which is essentially a natural 8iron rust10 is the metal1 iron1 held in the strong chemical grip of the gas1 oxygen1 which normally forms one-fifth of the air we breathe4 ,as you note1 the combination forms a substance entirely unlike either the iron or the oxygen1 but both of these can be regenerated from it 7the ore7 by chemical methods4 ,under influence of high heat 7this is one of the chemical methods1 by the way71 this stranglehold can be broken by carbon1 of which lampblack1 graphite1 charcoal1 and coke1 are our most familiar examples4 ,the result1 in the small1 crude1 and inefficient furnaces of long ago was a disappointingly small ball of crude iron1 pasty and scarcely meltable1 even at highest heats1 but soft and malleable when cold4 ,as mentioned1 it was a variety of what is now commonly called 8wrought iron40 ,illustration3 ,a ,,catalan ,,forge ,,with ,,italian ,,trompe1 ,,or ,,water ,,blower ,the ancients got this far4 ,but this was not 8cast iron40 ,when1 however1 much more charcoal was present in the highly heated furnace than was necessary simply to combine with the oxygen of the ore1 the liberated iron greedily absorbed enough of the extra carbon to change its own nature4 ,the metal then became very fluid1 whereas before it had been pasty and stiff even at much higher temperatures1 or1 indeed1 at white heat4 ,this liquid iron could be 8cast10 that is1 poured into molds and in that way made into various useful shapes4 ,it therefore became known as 8cast iron0 because of this property4 ,so the brittle metal 7cast iron7 in our kitchen ranges1 for instance1 is only the early malleable form of the metal surcharged with or having a large amount of carbon 7#c per cent to #e per cent7 in its make-up1 and it is this supercarbon content which confers the fluid quality while hot and the extreme brittleness when cold4 ,true1 there are other important constituents in our modern cast iron1 but for our present purpose they need not be dealt with4 ,it has been stated that the ancients got only as far as balls of wrought iron4 ,they really got further as their very fine sword steels show--the 8,wootz0 of ,india1 the 8,damascus0 of ,syria1 and later the 8,toledo0 of ,spain4 ,these they produced by heating rich ore in very small1 closed crucibles with just enough carbon 7pieces of wood or green leaves7 to make what we now call 8carbon tool steel40 ,as carbon steel is simply iron which has absorbed not over #b per cent of carbon 7cast iron described above has a supersaturation with its #c per cent to #e per cent of carbon and therefore is entirely different7 they were able to make it in small quantities4 ,when hardened by cooling quickly in water1 a forged-out blade of this product would cleave without dulling its edge a piece of iron1 it is said1 or cut cleanly a tuft of silk floss tossed into the air4 ,these steels attained well deserved renown4 ,while no one can desire to cast the slightest disparagement on the product of that period1 much of which was excellent1 astonishingly so considering the period1 a moment's consideration will convince one that modern products not only do not suffer in comparison but in reality are immensely superior4 ,the ancients had little or no knowledge of the reason for the proper qualities of their tools and they made the metal from variable materials in a crude way in such small quantities that little uniformity was possible4 ,while some of the product was undoubtedly excellent1 much must have been less desirable4 ,modern discoveries and inventions1 with the great mechanical progress of the last three centuries and the scarcely half-century-old application of chemical control1 have given during recent years products of great uniformity and marvelous quality4 ,what can compare with thirty thousand pound lots of steel turned out from one ,bessemer converter each seventeen minutes during the #bd hours in the day1 that is1 a total of #acjj tons or #b1fjj1jjj pounds1 in which not only the main controlling element1 carbon1 but also four lesser ones1 silicon1 manganese1 sulphur1 and phosphorus1 are held within extremely narrow limits2 or the modern blast furnace which produces a million pounds each #bd hours1 run with the same certainty of control8 ,modern high-speed steels which are every day being made have such high quality that tools formed from them will stand up for hours working red-hot under a lathe speed of two or three hundred linear feet per minute taking a deep cut and 8plowing out0 chips faster than a laborer can carry them away4 ,illustration3 ,,the ,,german ,,stuckofen ,modern war armament which has recently been so well advertised is sufficient answer as to whether modern metallurgy is in advance of that of centuries ago4 ,the only necessity for such comparisons is that it seems to be a failing of many to think that our forefathers were more wise and better in other ways than we4 ,it was but a few years ago that the fallacious announcement was made that during archeological excavations in ,egypt there had been found a fully equipped telephone system4 ,the inference intended to be conveyed1 of course1 was that ,bell's invention of the telephone had been antedated many hundreds of years4 ,illustration3 ,a ,,german ,,blast ,,furnace ,,of ,,fifty ,,years ,,ago ,the forerunner of the modern steels was crucible steel1 first made by ,huntsman about the middle of the eighteenth century4 ,previous to his time steel had been made by the 8cementation0 process by which method hammered-out bars of wrought iron were given a hard steel crust by heating to a red heat in charcoal or bone dust4 ,huntsman's product began to come so uniform and of such quality that his competitors were quite outdistanced4 ,it is related that one of them took advantage of a very severe storm to gain admittance to the forest forge of ,huntsman1 who1 he knew1 could not refuse shelter at such a time4 ,what he beheld was a very simple thing--the melting in a clay pot of pieces of cementation steel4 ,even to-day the crucible process is holding its own where quality is the main consideration4 ,it is the method by which practically all of the tool1 automobile1 and other special steels of to-day are manufactured and can hardly be given too high a rating4 ,the newly devised electric furnace process is the only possible competitor in sight4 ,of course for quantity and for lower cost the ,bessemer and the open-hearth processes are the only available ones1 but crucible steel has been the mighty factor in the commercial development of the world--at least until the latter half of the last century when the two other processes last mentioned began to acquire honor of their own without1 however1 detracting much from the importance of crucible steel as the steel of 8quality40 ,illustration3 ,,the ,,first ,,iron ,,casting ,,made ,,in ,,america ,though more interesting than any of the 8six best sellers0 much of the subsequent history of iron will have to be passed over at this time4 ,we can now only mention those very great and revolutionary discoveries and inventions which led to and absolutely are the basis of the quantity and excellence of modern irons and steels2 namely1 the trial for a time of coke made from pit coal by ,dud ,dudley of ,england and its failure which was turned into a great success a century later 7about #agac7 by ,abraham ,darby2 ,watt's invention of the steam engine in #aggj which made possible application of a strong continuous blast2 invention of the process of 8puddling0 of iron and of the rolling mill by ,cort about #aghd2 the introduction by ,neilson about #ahcj of the hot instead of the cold blast which increased blast furnace production fourfold2 the regenerative system of furnace heating invented by ,frederick and ,william ,siemens2 and the invention of the ,bessemer and ,siemens-,martin or open-hearth processes which provided methods for steel making on such an immense scale that this invaluable material was made available for general purposes4 ,it should be repeated that the inventions just mentioned have been of the utmost importance to the iron industry1 and through them only has it acquired its consequence of to-day4 ,without them we would not have the wonderful steel bridges1 the skyscrapers1 the gigantic steel ships1 the all-steel railway trains1 etc41 and the hundreds of iron products that are to-day so plentiful and so constantly about us that we disregard their presence4 ,it is difficult thus to pass them by1 but as most of them will be referred to in later chapters we must do so4 ,early iron making in ,america is of interest to us and must be briefly stated4 ,the colonists were aware of some of the iron ore deposits about them and sent samples to ,england where these yielded very fine iron4 ,in #afai a company known as the 8,london ,colony0 was sent out from ,england to engage in the manufacture of iron at ,falling ,creek1 near ,jamestown1 ,virginia1 but three years later all were massacred by ,indians4 ,it was many years before attempt was again made to manufacture iron in ,virginia4 ,about #afcg the ,general ,court of ,massachusetts granted to ,abraham ,shaw one-half of the benefit of 8any coles or yron stone wch shall bee found in any comon ground wch is in the countryes disposing40 ,apparently little resulted from this high-sounding grant4 ,real iron making in ,america began six years later with ,john ,winthrop1 ,jr41 and his 8,company of ,undertakers for the ,iron ,works0 which for many years operated in several localities in the ,new ,england ,states4 ,heaps of cinders left from their furnaces may still be seen and testify to their very extensive operation4 ,one of ,winthrop's men was ,joseph ,jenks1 who became known as the 8,tubal-,cain0 of ,new ,england4 ,what is claimed to have been the first casting made on the ,western ,continent was made by him4 ,it is a small pot1 which was acquired and is said to be still owned by the family of ,thomas ,hudson1 a descendant of ,hendryk ,hudson4 ,sand molding as used at present was introduced by an ingenious ,englishman1 ,jeremy ,floris1 and is vastly superior to the previously used system of molding in clay4 ,hollowware began to be extensively produced about this time4 ,as the country developed1 iron works sprung up here and there and various kinds of articles came to be regularly manufactured4 ,of the early plants we can only mention the ,stirling ,iron ,works1 at ,warwick1 ,new ,york1 which made the great #ahf-ton chain with links weighing #adj pounds each1 which spanned the ,hudson ,river near ,west ,point1 and where in #ahaf was cast the first cannon made in ,america2 the foundry of ,sharp ,curtenius1 in ,new ,york1 where was cast the first steam cylinder2 and the ,trenton ,rolling ,mills1 which first rolled iron as fireproof structural material4 ,before the ,revolutionary ,war the colonies exported considerable bar and pig iron to ,europe1 and as early as #agia ,england began to foresee that this country would eventually be a serious rival4 ,pittsburg's great advantage as an iron and steel center has been due to its proximity to an extensive seam of bituminous coal and ore in adjacent counties1 and to its location so near the ,great ,lakes1 which provided cheap water transportation for the ,lake ,superior ores4 ,the first iron works there was that of ,turnbull ,company1 which was established in #agij4 ,though ,reameur1 a ,frenchman1 is the accredited discoverer of the process of malleableizing cast iron1 ,seth ,boyden1 in a little shop in ,newark1 ,new ,jersey1 made malleable iron castings a commercial success4 ,illustration3 ,,two ,,modern ,,blast ,,furnaces1 ,,showing ,,skip-,,hoists1 ,,cast ,,houses1 ,,stoves1 ,,and ,,ore ,,pile ,the utilization of the great beds of high grade coking coal of eastern ,pennsylvania1 well known as the ,connellsville district1 and the discovery and development of the ,lake ,superior ore deposits have made the ,united ,states the leading producer of iron and steel of the world4 ,the development of the ,birmingham1 ,alabama1 district1 also has been a chapter of great importance but lack of space forbids description at this time4 ,we can have only a very slight appreciation of the debt which civilization owes to iron1 for practically everything we see or with which we daily come in contact contains or has resulted from application of iron in some way or other4 ,our cooking utensils and implements 7even the enameled and tinned ones71 the kitchen range1 the water and drain pipes1 and the furnace and heating plants of our houses1 are they not largely of iron8 ,our main building materials--the steel frames of skyscrapers and bridges1 and are not even wood1 brick1 stone1 and cement either shaped1 molded1 or of necessity made by aid of iron machinery8 ,the conveyances by which we travel--wagons1 automobiles1 street cars1 steam railways and steamships--how would they be possible without iron or steel8 ,consider the power plants of our factories1 of gas and electric lighting plants1 the pumping machinery and distribution systems of water works1 mines1 etc4 ,would the electric current which supplies so much of our power and light be known to-day or even be possible but for the magnetic properties of iron8 ,and how many of the materials and articles which we wear1 use1 and have about us constantly would be in any way possible without the wealth of steel machinery and tools which are available and absolutely necessary for their production8 ,the iron industry is often spoken of as the barometer of a people's civilization4 ,if all iron and iron products and their influence upon the world should be obliterated1 it seems impossible that we could be even started on the road to civilization4 ,no matter how we try1 probably none of us ever realizes the immensity and importance of the iron and steel industry with approximately #dfj huge blast furnaces here1 #ejjj cast and malleable iron foundries1 about #ajjj ,bessemer and open-hearth steel and some #cjjj puddling furnaces1 and the many thousands of factories which each day are turning the products of these into rails1 plate1 wire1 pipe1 and the infinitude of finished articles which enter into and are mighty factors of our civilization4 ,yet with these furnaces1 forges and factories at our very doors1 #ii4i per cent of us are entirely oblivious to their wonders and to their presence except to be annoyed by their noise and smoke4 ,even the blacksmiths and their service we scarcely note1 though they are daily fashioning for us a material which is vastly more important and more wonderful than any of the 8,seven ,wonders of the ,world40 ,,chapter ,,ii ,,the ,,raw ,,materials ,a story has it that a minister once visited a friend who was a zologist4 ,upon realizing for the first time how highly organized a creature was the humble earth-worm with its three-layer skin covering1 alimentary canal1 nephridia or excretory system1 reproductory organs1 rude nervous system1 and set for purposes of locomotion1 he exclaimed3 8,wonderful6 ,i had always supposed that worms were only skin and squash40 ,with millions of tons of heavy reddish-brown earth from northern ,michigan and ,minnesota going by our doors continuously during the shipping season1 the position of most of us is very similar to that of the minister relative to the earth-worm4 ,we know that something is going on but we are not aware of its importance or the immensity of it4 ,iron ,ore ,almost every one knows that there are extensive copper deposits along the ,lake ,superior shore of what is now northern ,michigan4 ,in the #agth century word of these was several times taken to ,europe where in old publications was mentioned a huge ingot of copper from which the ,indians chopped pieces with their hatchets4 ,at that early date maps of the region were drawn which are wonderfully accurate1 and1 from time to time over a period of a century and a half1 adventurers attempted to gain wealth in this favored region4 ,illustration3 ,,map ,,showing ,,distribution ,,of ,,iron ,,ores ,,of ,,america ,however1 despite the definite knowledge of considerable mineral wealth there and rumored claims of much more1 ,michigan at the time of her admission to the ,union in #ahcf bitterly opposed having what is now the northern peninsula included within her territory in lieu of a ten mile wide strip of northern ,indiana and ,ohio1 and it has been said that she nearly went to war to resist it4 ,even after the discovery of the iron ore deposits1 no one realized the full importance of the minerals of this region4 ,illustration3 ,,showing ,,typical ,,mesaba ,,ore ,,bed ,,which1 ,,after ,,earth ,,covering ,,is ,,removed1 ,,becomes ,,an ,,open ,,pit ,,mine ,during the many years of campaigning for ,federal help in the building of a canal at ,sault ,sainte ,marie1 the fisheries1 valued at #a1jjj1jjj a year1 were given as the leading reason why a canal should be built1 and it was no less a personage than ,henry ,clay1 who1 in opposing appropriation for this purpose1 referred to the project and the district as 8beyond the remotest settlement1 if not in the moon40 ,now1 within eighty years of that time1 the annual tonnage of shipping passing through the ,sault ,sainte ,marie canal is as great as the combined tonnage from the ports of ,new ,york1 ,london1 ,liverpool1 ,antwerp1 and ,hamburg1 and1 as against the #a1jjj1jjj value of the fisheries1 the value at the mines of the ore alone shipped from this region amounts to about #ajj1jjj1jjj yearly4 ,illustration3 ,,shenango ,,open ,,pit ,,mine1 ,,chisholm1 ,,minn4 ,illustration3 ,,interior ,,of ,a ,,hard ,,or ,,lump ,,ore ,,mine ,as the copper deposits are mostly along the shore of the lake and the great iron ore beds occur seven or more miles inland1 the latter were not discovered until ,sept4 #ai1 #ahdd1 when ,william ,a4 ,burt1 a ,deputy ,united ,states ,surveyor1 noticed that the needle of a solar compass of which he was the inventor became unreliable4 ,in looking about to discover the magnetic source which must be the cause of the variation1 members of his party discovered ore just beneath the sod near what is now ,negaunee1 ,michigan4 ,inventor-like1 ,burt's only concern was to devise some preventive for future interference by stray magnetic currents4 ,he simply noted in his book that there was here a deposit of iron ore and neither he nor any of his party profited or apparently attempted to profit from the discovery4 ,illustration3 ,,showing ,,ore ,,body ,,and ,,shaft ,,method ,,of ,,mining ,the ,indians seem to have had no previous knowledge of these ore deposits4 ,the first shipments of ore naturally were samples taken from what afterward came to be known as the ,jackson mine and trials of them in blacksmiths' forges were made at ,jackson1 ,michigan 7from which town went the first seriously-minded pioneer1 ,philo ,m4 ,everett71 and at ,cucush ,prairie4 ,they were soon afterward tried in a blast furnace at ,sharon1 ,pa4 ,the first plan was to build forges and manufacture iron near the mines4 ,so there was established on ,carp ,river a forge to which the ore was hauled in winter when the ground was frozen4 ,it turned out1 however1 that while very good bar iron was manufactured here1 it could not be delivered in ,pittsburg at a cost less than #bjj a ton4 ,as the market rate for iron then was but #hj a ton the plan was not financially successful4 ,illustration3 ,,lighting ,,the ,,fuses ,,in ,a ,,shaft ,,mine ,attention was turned to the shipping of ore to furnaces better located as regards coke supply and market4 ,it was possible to make this a profitable undertaking only through cheap ore handling and transportation4 ,so1 to-day1 the ore which is better adapted than the other raw materials for handling by labor-saving devices and transporting without deterioration1 is taken to the coke and limestone1 and to the market for the product4 ,while the weight of coke used is but half that of the ore smelted1 its greater bulk1 loss by breakage when handled in quantities1 and deterioration upon exposure preclude its manipulation in the way which would be necessary to get it to the ore4 ,illustration3 ,,view ,,of ,,hull-,,rust ,,mine1 ,,near ,,hibbing1 ,,minn4 ,the marvelous development of this territory into the greatest ore producer of the world1 including the hauling of the first small shipment on mule back1 the building of the plank and then the 8strap0 railroad with grades so steep that the small trucks often ran over and killed the mules1 the building of the steam railroad1 the successive building and enlarging of canal locks at ,sault ,sainte ,marie connecting for use of ever larger and larger ore boats the waters of ,lake ,superior and ,lake ,michigan1 and the growth of ore boat fleets to such size that during the shipping season scarcely ever is one boat out of sight of another over the entire #hjj mile journey from ,duluth to the furnaces along ,lake ,michigan and ,lake ,erie1 is within the memory of men still living4 ,marquette was the shipping point during the earlier days and the history of this and adjacent regions during the latter half of last century vies in pioneering flavor with the tales of our early western frontiers1 and with the more recent ,yukon mining camps4 ,illustration3 ,,the ,,routes ,,by ,,which ,,lake ,,superior ,,ores ,,go ,,to ,,the ,,furnaces ,the first two mines1 the ,jackson and the ,marquette1 have come to be particularly well known historically4 ,the development of these and other ranges in northern ,michigan and ,minnesota1 particularly the ,menominee1 ,gogebic1 ,vermillion1 etc41 and1 since #ahij1 the ,mesaba and ,cuyuna1 have brought about revolutions in ore digging1 handling and transportation1 which followed each other with extreme rapidity4 ,the ore carrying boats1 for instance1 may almost be said to have jumped from a length of three hundred to six hundred feet1 and the ,sault ,sainte ,marie canal locks were several times almost immediately outgrown1 though rebuilt again and again1 each time so much larger than before that they were deemed impossible to be outgrown4 ,illustration3 ,,loading ,,ore ,,at ,,an ,,open ,,pit ,,mine ,illustration3 ,,showing ,,other ,,typical ,,ore ,,bodies1 ,,shaft ,,mined ,practically all of the ore beds1 with the exception of the ,mesaba1 yield hard or lump ores and most of them are shaft mines in which mining has to be done underground and the ore blasted down4 ,blast furnaces had never used any but lump ores when along came discovery of the immense soft ore deposits lying just beneath the surface of the ground over a region one-hundred miles long in what is known as the ,mesaba district of ,minnesota4 ,these soft ores were so accessible and so rich that they drew the attention of the iron makers of the whole country4 ,but1 alas6 ,while perfectly good in every other respect1 they were merely dry powder and not adapted to blast furnace methods4 ,there were great discussion1 excitement1 and ridicule among or at those who invested in these soft ore mines4 ,eventually1 of course1 blast furnace men worked out feasible methods of converting soft or what are termed 8,mesaba ,range0 ores into iron in the blast furnace4 ,those brave spirits1 who in the face of ridicule dared to invest in and develop ,mesaba properties1 have long been reaping their financial reward which still shows no sign of diminishing1 as 8,mesaba ,range0 mines are 8the0 mines of to-day4 ,illustration3 ,a ,,close ,,view ,,of ,,the ,,hoover ,,mason ,,unloaders ,while it may be done1 it has not been found desirable to make up the entire 8burden0 or furnace charge of soft ores alone as long as lump or hard ores are obtainable to mix with them1 but often more than half is soft ore4 ,illustration3 ,,starting ,,an ,,open ,,pit ,,mine4 ,,the ,,earth ,,covering ,,is ,,being ,,removed ,while ores from the shaft mines1 called 8,old ,range0 ores1 are won by going down into the earth sometimes as far as #c1jjj feet1 drilling holes in the rock1 blasting down the ore1 and loading it into buggies which are hoisted to the surface1 8,mesaba ,range0 ores are made available by simply 8stripping0 off the thin earth covering1 then caving or loading with steam shovels the soft ore into railway cars4 ,some of the illustrations presented show the ore trains and shovels1 and the manner in which the open pits are worked in terraces4 ,one naturally wonders how it is possible to mine and carry these ores to the shipping ports of ,duluth1 ,superior1 ,two ,harbors1 ,marquette1 ,ashland1 ,escanaba1 etc41 put them aboard ore carrying boats1 transport them by steam power to ,milwaukee1 ,chicago1 ,gary1 ,detroit1 ,cleveland1 ,pittsburg1 ,buffalo1 and the many other iron centers and convert them into iron and steel at a profit4 ,this1 of course1 is only possible because of the inventive genius of man4 ,for every operation ingenious machinery has been constructed which has brought the cost of such operations to its lowest terms4 ,illustration3 ,,unloading ,,cars ,,of ,,coal ,,or ,,ore ,,is ,a ,,simple ,,matter ,,with ,,the ,,modern ,,car ,,dumper ,illustration3 ,,ore ,,cars ,,are ,,unloaded ,,by ,,gravity ,,at ,,docks4 ,,the ,,chutes ,,then ,,convey ,,the ,,ore ,,from ,,the ,,ore ,,pockets ,,into ,,the ,,boat',s ,,hold ,by modern methods the cars carrying the ore from the mines are run up trestle-work into positions above the ore bins high over the docks4 ,the mammoth ore carrying boats are merely steel shells with quarters for crew and machinery at bow and stern1 and hatches built with exact twelve foot centers between4 ,they are tied alongside the dock1 long steel chutes1 also spaced twelve feet apart1 are lowered along most of the length of the boat and the ore slides into the vessel's hold evenly all along as it has to do1 else the buoyancy of lighter parts of the boat might break the frail shell4 ,the entire load of #aj1jjj tons of ore is ordinarily taken aboard in less than one hour4 ,pulling out immediately the vessel traverses ,lake ,superior1 the ,sault ,sainte ,marie canal1 ,lake ,michigan or ,lakes ,huron and ,erie as the case may be1 and ties up at the dock at destination4 ,years ago it would have been unloaded by men with buckets or wheel-barrows1 requiring some days at best4 ,now1 however1 the hatches are uncovered and several ore unloaders with huge clam shell buckets taking as high as fifteen tons of ore at a 8bite0 descend like vultures upon it4 ,within four or five hours the boat is again empty with no manual labor having been done upon the ore from the mine to the furnace pile with the exception of a little heaping up of the ore in the corners of the boat's hold1 which the ore unloaders could not reach4 ,illustration3 ,,hoover ,,mason ,,unloaders ,,at ,,the ,,illinois ,,steel ,,co41 ,,south ,,chicago1 ,,ill4 ,a young man named ,alexander ,e4 ,brown could not bear1 in the old days1 to see the ore so awkwardly unloaded1 and in #ahhj started the procession of ore unloading devices4 ,there are now several successful ore unloaders of which the ,brown hoist1 the ,hoover ,mason1 and the ,hulett are probably the best known4 ,with the ,hulett unloader the operator has to be an aviator1 as his position is directly above the grab bucket4 ,he descends into the hold with the bucket1 comes up with it and is with it in its entire journey from the boat's hold to the dump and back again4 ,it must be dizzy business4 ,illustration3 ,,the ,,hulett ,,unloader4 ,,note ,,the ,,operator',s ,,head ,,in ,,white ,,spot ,,just ,,above ,,the ,,grab ,time is too precious to hold the boat at the dock long enough that each bucketful1 large as it is1 can go directly to its final bin4 ,it is dropped just back of the unloading machine from which it is again picked up by other buckets which carry it back toward the furnaces and deposit it in cement ore troughs awaiting further journey to the ore house1 from which it goes to the furnaces4 ,the empty ore boat immediately coals with whole car loads of the fuel dumped into chutes leading to her bunkers by the car dumper and proceeds on her way back to the mines for another cargo of ore4 ,the round trip1 including loading and unloading1 requires but seven days4 ,illustration3 ,a ,,good ,,view ,,of ,,the ,,hatch ,,system ,,of ,,modern ,,ore ,,boats ,,and ,,four ,,hulett ,,unloaders ,,at ,,work ,as in many other lines of commercial endeavor of to-day1 speed and large tonnage have been the aim and it would seem that in ore handling and conveying devices the limit has about been reached4 ,the big steam shovels1 gravity docks1 ore tanks or boats1 and unloading and coaling devices1 with the low cost of water transportation have made our modern iron and steel preminence possible4 ,to show the importance to us of this water transportation1 we might mention that the rate for carrying ore from ,lake ,superior ore ports to the ,lake ,erie furnaces has been as low as 4#jjjg per ton per mile while the transportation cost by way of a well operated railway at that particular time was more than 4#jje per ton per mile--more than seven times as much4 ,illustration3 ,,the ,,rehandling ,,bridge ,,with ,,stock ,,ore ,,pile ,,and ,,blast ,,furnace ,,at ,,rear ,though for some years past more than three-quarters of all of the iron ore used in the ,united ,states has come from seven or eight mines in the northern peninsula of ,michigan and the adjacent part of ,minnesota1 it must not be understood that the ,lake ,superior mines are the only ore deposits in this country4 ,figures show that such an inference is far from the truth4 ,it is true1 however1 that they have made the ,united ,states what it is1 the leading iron producer of the world4 ,there are still immense quantities to be mined on the ,lake ,superior ranges4 ,their heavy production of cheaply handled high grade ore has1 of course1 held back development of other districts1 which also have great natural resources4 ,the ,birmingham1 ,ala41 region for instance1 is a great ore and iron producer1 right now producing the third largest tonnage of any district in the country4 ,some time in the not far off future1 ,alabama with her great deposits of iron ore1 coal1 and other natural resources is going to announce herself in no small voice4 ,new ,york1 ,pennsylvania1 ,tennessee1 and ,virginia rank next after ,minnesota1 ,michigan1 and ,alabama as ore producers1 and several other states of the ,union are not paupers in resources of iron ore4 ,illustration3 ,,hulett ,,grab ,,buckets ,,in ,,the ,,hold ,,of ,,an ,,ore ,,boat ,we should not get so enthusiastic over our ore supply and iron production as to think that other countries are devoid of such material4 ,almost every civilized country has ore enough that it does pretty well4 ,with many the trouble is that the ore has objectionable constituents or that supply of cheap fuel is not available4 ,germany has large deposits of iron ore1 but until the invention of the basic ,bessemer process about #ahgj she was handicapped because of the high phosphorus content of her ore4 ,the basic processes1 both ,bessemer and open-hearth1 allow of the removal of this phosphorus during the conversion into steel1 and they therefore brought ,germany to the front as an iron producer4 ,the excellence of ,sweden's iron and steel has long been known the world over4 ,sweden produces approximately one per cent of the world's total production of iron and steel1 but her ore has been of such high grade that iron made from it has maintained its position as a standard for use in the manufacture of highest grade crucible steels4 ,the very finest steels for cutlery and tools1 and even the softer grades of steel of northwestern ,europe1 have been made from ,swedish iron as a base4 ,iron ore1 of course1 is classified by geologists and chemists into varieties with such names as hematite1 magnetite1 siderite1 etc41 which here little concern us4 ,to be worked at a profit1 the iron content of the ore must be high with the smallest possible amounts of undesirable impurities1 particularly phosphorus1 sulphur1 and silica4 ,there are1 however1 certain impurities which are not undesirable1 for instance1 lime1 which will act as a flux and neutralize the effect of some of the undesirable impurities4 ,for these reasons the prices for iron ore are based on the iron content and modified by the relative amounts of undesirable and desirable impurities4 ,phosphorus is almost a domineering factor and at present approximately fifty cents a ton more is paid for ,bessemer ore 7that containing less than 4#jej per cent phosphorus7 than for non-,bessemer ore4 ,as might be expected the best ores have been the first used and the grade is constantly falling4 ,instead of the #ff per cent iron ores of some years ago those coming nowadays contain not much more than #ei per cent of iron and the ,bessemer ores described above are getting scarcer1 so that for some years practically all of the furnaces have been mixing with them as much higher phosphorus ore as could be used without pushing the phosphorus content of the mixture over the allowable limit4 ,we often hear people surmising what is to become of us when all of the iron ore of this planet has been used4 ,there is no harm in taking stock of resources and in this case it does us much good4 ,it happens that each time the count is taken of iron ore available and that which under future and better methods of working can be utilized1 we find ourselves immensely better off than the previous report had made out and we have less cause to worry about the future4 ,the last inventory was taken by the extremely ambitious ,international ,geological ,congress held at ,stockholm1 ,sweden1 in #aiaj4 ,it shows that the world yet has enough rich ore to make #aj1aib1jjj1jjj tons of iron1 and1 a further supply of ore for #ec1acf1jjj1jjj tons of iron1 which could be used if necessary4 ,so we will get along for a while yet4 ,,chapter ,,iii ,,the ,,other ,,raw ,,materials ,illustration3 ,,old ,,charcoal ,,kilns1 ,,near ,,negaunee1 ,,mich4 ,since the beginnings of iron manufacture1 charcoal has been a favorite fuel4 ,though during the past two centuries coke has grown to be the standard1 with anthracite and some few bituminous coals finding use in certain favored localities1 charcoal may be considered the fuel which developed the iron industry1 at least until recent years4 ,charcoal ,as most of us know1 charcoal is completely charred wood1 usually hard wood1 though sometimes resinous or other soft woods are used4 ,of well-dried timber more than #ej per cent by weight is moisture4 ,this and certain other constituents are driven off by heat in the absence of air1 which process is usually called 8destructive distillation40 ,by primitive methods a considerable part of the wood was completely burned and wasted during the production of charcoal4 ,stacked in piles or long rows the cut wood was well covered with earth1 except for a small opening at the top through which the fire was lighted down a center cavity left to the bottom of the pile4 ,the air coming in through the opening at the top was sufficient to keep the wood smoldering4 ,after a period1 which had been shown by experience to give the best results1 the opening was closed and the fire smothered4 ,illustration3 ,,beehive ,,coke ,,ovens ,brick ovens of the beehive shape were built at a later date where considerable charcoal was to be made4 ,these were operated on much the same general principle as the meillers or earth-covered piles1 described above4 ,the fire was lighted at the bottom of the central cavity of the corded wood1 the only air at first coming from the top1 though later in the process a little was admitted through holes in the walls4 ,after about ten days1 when gas ceased to come off1 the kiln was tightly closed for a period of twenty days more for the fire to die out and the charcoal to cool4 ,by both of these processes valuable constituents were burned or driven off by the heat and lost4 ,these were mainly methyl alcohol1 acetic acid1 and wood tar4 ,modern industry so emphatically disapproves of any waste of materials that apparatus has been devised to produce charcoal which allows of recovery of the by-products at the same time4 ,in northern ,michigan1 which is practically the only district in the ,united ,states in which the charcoal industry as an industry still survives1 long steel tubes or retorts are built with brick fire-boxes under each end1 much as a stationary boiler is set4 ,into these retorts are run steel cars loaded with the wood4 ,the retorts being closed1 the heat drives or distills off the moisture and gaseous compounds through pipes connecting them with condensing apparatus4 ,after about twenty hours the wood has been charred1 the doors of the kilns are suddenly opened and the cars are rushed into other and similar retorts for cooling1 while fresh loads of wood replace them in the first4 ,illustration3 ,,standard ,,beehive ,,coke ,,oven ,illustration3 ,,beehive ,,ovens ,as may be surmised vast quantities of wood and of wood-producing land are required for extensive charcoal manufacture1 and this is the most serious problem for the manufacturer of charcoal4 ,several square miles of timber land must be cut over each year and the wood efficiently transported in order to operate a large plant profitably4 ,pig iron as a by-product is a rather novel idea1 but that is practically what the charcoal pig iron produced in our ,lake ,superior region is4 ,several companies operate wood distillation plants for the production of methyl alcohol1 acetic acid1 acetate of lime1 etc41 and use their charcoal in the manufacture of charcoal pig iron from the ores so close at hand4 ,the very low sulphur content and the small amount of ash have been the great advantages possessed by charcoal over other solid fuels4 ,resulting characteristics made charcoal pig iron a former favorite for manufacture of certain articles such as chilled car wheels1 etc41 and it1 therefore1 brought a higher price than coke pig iron4 ,during recent years1 however1 by careful selection of coal and improvements in the coking process the sulphur and ash of coke have been so reduced that charcoal has not so great an advantage as formerly4 ,charcoal iron to-day brings only about #a4ej per ton more than coke iron2 whereas1 the differential a few years ago was as great as #e4jj or #f4jj per ton4 ,charcoal is quite fragile and structurally weak1 so much so that blast furnaces for its use cannot be built higher than sixty feet2 whereas1 the great strength of coke allows them to be built to exceed one hundred feet in height with correspondingly increased output4 ,what this means may be realized by every one conversant with the demands of modern industry4 ,coke ,illustration3 ,,charging ,,coal ,,into ,,the ,,ovens ,as charcoal is completely charred wood1 so coke for analogy's sake may be said to be completely charred coal1 practically always of the bituminous type4 ,by 8baking0 bituminous coal at a cherry-red heat1 its volatile constituents are driven off as the well-known 8coal-gas0 of almost every small town1 and a strong1 brittle and porous material or coke residue is left4 ,if the baking is done without any admission of air to the retort1 practically none of the coal burns and the 8cake0 or coke which is left contains the ash of the original coal and what is known as the 8fixed carbon10 i4e41 carbon which cannot be distilled or driven off by heat alone1 though it would burn were air admitted4 ,the gases or volatile constituents which are given off consist mainly of moisture and a mixture of gaseous chemical compounds1 which are known as 8hydro-carbons40 ,these contain that part of the carbon of the original coal which does not remain as 8fixed carbon0 in the coke4 ,illustration3 ,,quenching ,,after ,,coal ,,has ,,been ,,coked ,just why some coals will coke while others of apparently the same composition as shown by the chemist's analyses1 will not1 but instead of the hard brittle mass will leave a heap of brown or black powder1 is not as yet definitely known4 ,it is easy enough for chemists to determine with accuracy the amounts of hydrogen1 nitrogen1 oxygen1 carbon1 sulphur1 and other elements2 but it is a difficult and perhaps an impossible matter to determine just how these elements are 8hitched up0 in the very complex mineral1 coal1--one of the most complex substances which we know4 ,various theories have been advanced in the attempt to explain the coking quality4 ,a bulletin of the ,united ,states ,geological ,survey claims that the relative percentages of hydrogen and oxygen in the coal determines it2 others have held that it depends upon the compounds of a tarry or asphaltic nature present4 ,the fact remains that some coals coke without trouble1 while others do not coke at all4 ,as yet the only real way to tell whether a new variety of coal will or will not coke is to try it4 ,since #agac1 when ,abraham ,darby in ,england succeeded in introducing it as a substitute for the fast disappearing charcoal for use in blast furnaces1 coke has become the standard fuel4 ,it is very strong and will bear up under the great weight of iron ore and limestone with which the furnace is charged4 ,so furnaces for use with coke may be built much larger than those in which charcoal is to be the fuel4 ,the porous nature of coke allows it to burn rapidly with intense heat1 so that the output of an iron works is greatly increased through its use--a very desirable thing in these days of big things4 ,it has its disadvantages1 of course1 mainly high sulphur1 a deleterious substance for which molten iron1 unfortunately1 has a voracious appetite1 and a rather high percentage of ash which must be fluxed out4 ,but all in all1 it is a very desirable fuel for blast furnace and other metallurgical purposes1 as is shown by the fact that it is used in the production of about ninety-nine per cent of all iron and steel now made4 ,illustration3 ,,drawing ,,the ,,coke ,what is known as the ,appalachian coal region produces coal for more than seventy-five per cent of the coke made in the ,united ,states4 ,this region includes the strip of territory extending from ,western ,pennsylvania and ,ohio down to ,tennessee1 ,georgia1 and ,alabama4 ,the famous ,connellsville district is a part of this region4 ,illinois and ,indiana have a great deal of coal1 which1 however1 has rather indifferent coking qualities4 ,almost constant experimentation has been carried on in the attempt to induce these semi-coking coals to coke4 ,the best that has so far developed is the use of a considerable percentage of them in admixture with coals of good coking qualities4 ,such mixtures yield quite satisfactory coke4 ,the ,beehive ,oven ,process ,illustration3 ,,large ,,pieces ,,of ,,coke ,in the old days there was no desire or incentive to avoid waste of coal resources4 ,if during the coking process some air got into the oven and part of the coal was burned1 or if all of the gas given off was wasted1 it did not matter4 ,there was plenty more of coal and the thing desired was to get the requisite coke in the quickest and cheapest way4 ,illustration3 ,,where ,,coals ,,are ,,pulverized ,,and ,,mixed ,,for ,,coking ,in ,western ,pennsylvania1 ,ohio1 and ,virginia1 were great beds of high grade coking coal4 ,in this region and particularly around ,pittsburg1 numerous blast furnaces and steel mills grew up4 ,the coke for these was made in the most convenient way--in the wasteful beehive ovens4 ,illustration3 ,,battery ,,of ,,by-,,product ,,coke ,,ovens1 ,,showing ,,gas-,,collecting ,,main ,as the name signifies1 these ovens or retorts are brick chambers shaped like beehives4 ,in the larger plants they are built either in single rows against long hills or in double rows back to back4 ,over the tops of the ovens in each row runs a car called a charging 8lorry40 ,coal is poured from the bottom of this through a hole in the top of each oven while it is still hot from the preceding charge4 ,no air gets in except that admitted through the hole in the oven top and a small slit left over the one side door1 through which the coke is drawn when the coking process is finished4 ,the heat of the oven starts the distillation of the moisture and the volatile compounds which escape through the hole in the oven top4 ,the small amount of air admitted burns a little of the coal and gas and raises the temperature of the oven to that required for coking4 ,after #dh or #gb hours a spray of water is thrown in over the glowing coal to quench the fire4 ,the partially cooled coke is drawn through the open door1 sorted and loaded into cars for shipment4 ,though this method of coking is a very wasteful one1 it yet produces the larger quantity of the coke made in the ,united ,states4 ,however1 conditions are rapidly changing and it will not be many years before the much less wasteful 8by-product0 process gains the ascendency4 ,by #aiad it had already come to produce about twenty-five per cent of the total coke made here1 and since that date the percentage has been rapidly increasing4 ,the ,by-product ,process ,illustration3 ,,top ,,of ,,ovens ,,with ,,charging ,,bin ,,and ,,lorry ,,at ,,far ,,end ,by this system of coking a greater yield of coke is obtained and most of the by-products are saved4 ,the value of the latter depends largely1 of course1 upon local conditions1 such as transportation1 costs of the material1 cost of labor1 and available market for the coke oven gas4 ,they are usually figured as having a value of #a4ej per ton of coal coked1 equivalent to a total of #ga1jjj1jjj per year for the coal coked in the ,united ,states4 ,illustration3 ,,lorry ,,for ,,charging ,,coal ,,into ,,ovens ,the ovens and apparatus required are considerably more expensive1 but1 since this industry has developed in this country during the last twenty-two years to a point where one-quarter of all of the coke manufactured is made by the by-product process1 there can be no doubt that it is a profitable proposition and that eventually the wasteful beehive ovens will be a thing of the past4 ,practically all of the types of by-product coke ovens in use have been developed in ,germany or ,belgium1 where circumstances forced earlier conservation of resources than in this country4 ,the three best known types are the ,semet-,solvay1 the ,otto ,hoffman1 and the ,koppers--the latter a recent arrival4 ,they differ mainly in details of construction and operation4 ,illustration3 ,,machine ,,for ,,pushing ,,coke ,,from ,,ovens ,in a general way a 8battery0 of coke ovens consists of from #dj to #hj long narrow brick-walled chambers placed closely side by side with heating flues or 8checker-work0 between them4 ,the fire for the baking process is in these flues1 which are interconnected1 and the heat developed is sufficient to drive off the moisture and volatile substances of the coal in the narrow chambers just on the other side of the brick walls4 ,charging is done by a 8lorry0 as in the beehive process4 ,after from seventeen to twenty-four hours at a red heat1 the coke is 8pushed0 from the ovens1 one after another1 by an electric ram which enters at one end4 ,the #cj #g #a foot block of glowing coke emerges from the other end1 where1 breaking under its own weight into good-sized pieces1 it falls into a steel car on a track just beneath4 ,a spray of water quenches it and it is taken to the storage bins to be sorted4 ,rich coal-gas is the main by-product4 ,that which comes off during the first seven hours is the richest and has the greatest illuminating or 8candle0 power4 ,after washing free from dust1 tar1 ammonia1 etc41 the gas is usually run into holders or tanks from which it is distributed for use for illuminating or for heating purposes4 ,that which comes off during the latter part of the coking period has much less of those constituents which give illuminating value4 ,it has good heat value1 however1 and as fuel is required for keeping the ovens up to the coking temperature1 this poorer gas from the coking chambers is switched into and burns in the flues between the coking chambers as mentioned4 ,thus the larger part of the gas is sold to customers1 usually in the city near which the ovens have been located1 and the poorer part is utilized in heating the ovens and the steam boilers which run the plant4 ,illustration3 ,,quenching ,,car ,,awaiting ,,its ,,load ,the coal tar1 which the ,german chemists have made so famous through its manufacture into the almost endless variety of beautiful dyes1 is another of the by-products which is recovered by this1 but burned or lost in the beehive oven process4 ,from a long main over the tops of the ovens which connects the gas pipes1 the tar flows along with the gas to the scrubbing and gas cleaning plant1 where by rather intricate operations it is freed from other substances4 ,in this country much of the tar is used for building purposes1 etc41 and some as fuel1 but not much has been made into the chemical products for which ,germany is so famous4 ,for a long time a few dyes and other chemical compounds have been made here from coal tar4 ,since the early days of the war in ,europe and the cessation of imports of such materials on this account1 there has come about considerable expansion in their manufacture here2 but it is doubtful if the time is yet ripe for a wholesale entry into the manufacture of these coal tar 8derivatives10 especially the very extensive variety of dyestuffs4 ,naphthalene and benzol from which many other chemical compounds as well as munitions of war can be made1 are among the by-products4 ,illustration3 ,,quenching ,,the ,,coke ,most of the ammonia which the corner drug store sells1 comes from the by-product manufacture of coke4 ,the largest part of the ammonia which is produced in the process1 however1 is manufactured into sulphate of ammonia1 a well-known fertilizer4 ,coal ,anthracite or hard coal has been used in certain districts in the ,united ,states1 especially in ,new ,jersey and eastern ,pennsylvania4 ,it is not an ideal fuel as it is too solid to burn rapidly1 spalls or cracks under heat and interferes with the blast4 ,since #ahfj when coke became available here much less coal has been used1 though some is yet used in admixture with coke4 ,some bituminous coals which contained little tarry matter also have been used in this way4 ,fluxes ,limestone1 the rock which is ordinarily used for fluxing purposes1 needs no introduction to any of us4 ,as the marble of statuary1 the material of which oyster and other sea shells and the white tombstones of our cemeteries are composed1 it is well known4 ,any of these varieties of the material may be used for fluxing purposes1 but usually it is limestone which is quarried for the purpose or obtained as chippings or spalls from building blocks4 ,illustration3 ,,coke ,,going ,,from ,,quenching ,,car ,,to ,,bins ,illustration3 ,,loading ,,coke ,,in ,,box ,,car ,the active agent1 which produces the chemical or fluxing action in the blast furnaces1 is carbonate of calcium 7lime7 of which limestone contains about #ih per cent4 ,dolomite is a mixture of carbonates of lime and magnesium1 about #ec per cent of the former and #de per cent of the latter1 and is sometimes used in place of limestone4 ,fluor spar1 a rock composed of calcium and fluorine1 is used in small quantities in some of the metallurgical processes4 ,it is a very powerful flux4 ,,chapter ,,iv ,,the ,,blast ,,furnace ,up the dark tower shoots the elevator with its 8buggy0 of coke4 ,its speed is not conditioned to the comfort of man1 who is not supposed to be a passenger1 except the occasional laborer whose duty as buggy-pusher requires his presence on twelve-hour shifts at the top4 ,so we1 whose exploratory proclivities have led us at the office to sign away our lives for grant of a pass to the blast furnace1 find our breath about taken from us with the first mad dash into the darkness of the climb4 ,that stone tower had looked much more innocent from below4 ,but now the rickety elevator has as suddenly emerged into the light again and stopped abruptly at the charging floor which extends across the chasm to the top of the furnace4 ,as the smoke-begrimed buggy-pushers rush the buggy of coke across to the furnace bell1 we have opportunity to notice that we are a full hundred feet above ground4 ,just here1 seemingly so close that we can put our hands on them1 in a row1 are the round steel tops of the four stoves which are for the purpose of preheating the blast4 ,the huge pipes1 dust arresters1 tanks1 and buildings1 all so necessary to the plant1 look almost like a tangled mass from our high station1 while the charging floor upon which we stand1 the shoulder-high steel fence around it1 the furnace top1 the adjacent stoves and in fact everything for a half mile around us1 is colored yellow-red with iron dust4 ,we understand the reason for this when the buggies of ore which have succeeded the coke are dumped into the funnel-shaped depression around the conical bell at the center4 ,as the huge bell is lowered and the charge slides in there is considerable blowing out of the fine ore dust1 which1 in fact1 continually 8oozes0 out of all crevices under the heavy pressure of the blast inside4 ,illustration3 ,,hand-,,fed ,,blast ,,furnace ,day and night1 month in and month out1 during the life of the fire-brick lining of the furnace1 this routine of charging1 first coke1 next the theoretically correct charge of analyzed iron ores1 then limestone1 in rotation goes on4 ,from #f ,a4,m4 to #f ,p4,m4 and from #f ,p4,m4 to #f ,a4,m4 on twelve-hour shifts1 alternating gangs of laborers push the buggies across to the furnace top1 dump and return them to the elevator already up with another load4 ,the incessant quiver of the iron plates beneath our feet with the rumbling and groaning from the inside of this monster are disquieting and the thought constantly recurs3 8,what if this powerful creature should just now rebel1 as quite occasionally occurred in the old days when all of its moods had not been so well understood80 ,for this king of metallurgical devices1 though gentle and obedient as a lamb under proper treatment1 is a domineering fury when it has dyspepsia as occurs whenever its attendants are remiss in their attentions to its diet4 8,those explosion doors just below the furnace top--are they in working order and would they be adequate80 ,but whether1 as in recorded instances1 the whole furnace top is torn off as evidence of its wrath1 or its displeasure is exhibited in a milder way1 we much prefer to be absent4 ,the thought is disquieting and we are glad to leave4 ,illustration3 ,,cinder ,,or ,,slag ,,flowing ,,into ,,ladles ,illustration3 8,,fireworks0 ,,at ,,the ,,cinder-,,notch ,unwilling to test again the elevator for the downward trip1 we take to the narrow iron stairway which leads from the top of the furnace to the ground4 ,but this is worse than the elevator1 for the stair treads are very narrow and made only of three slender iron rods4 ,to our palpitating hearts they seem to give very insecure foothold and the gaps show that there is nothing but earth beneath us1 and that a hundred feet below4 ,to make matters worse1 before we creepingly get half way down some visitors below have stopped to watch our slow and trembling steps and our nervous clutch on the low 8stingy0 hand rail4 ,we hear them innocently inquire of one another why we move so slowly4 ,we wish that we could appear brave1 especially before the women in the party1 but we could not move with greater alacrity if our lives depended upon it4 ,once below again with our breath regained1 things are more interesting4 ,the red-hot molten slag which has just been tapped out is running from the furnace along a long trough into a ladle six feet high resting upon a car on the railway track alongside the 8cast house10 as the huge structure which houses the lower part of the furnace is called4 ,this smoking1 molten slag stream gives off a powerful sulphur smell and throws a lurid glare over everything round about4 ,illustration3 ,,the ,,slag ,,dump ,the furnace superintendent is just explaining to the other party that ,no4 #b furnace has been 8hanging0 for a couple of days and is still dangerous4 8,if you realize10 said he1 8the great weight of coke1 ore1 and limestone in that furnace1 you can see what a splash it would make if the clogged1 bridged part with all above it should fall suddenly into the molten pool in the #8hearth' of the furnace4 ,two years ago ,no4 #a broke out and the molten metal caught and burned to death one of our men and injured several others4 #8,hanging' does not occur when the furnace is working right1 but failure of the charge to come down evenly is very serious sometimes4 ,a blast furnace is like a coquette2 she has to be handled just so1 and even then you cannot always be sure what she is going to do next4 8,oh yes1--where does the iron come from8 ,well1 we often read nowadays of a man and his #8affinity4' ,now the chemist has used that word #8affinity' for years to describe the liking or attraction of one chemical #8element' for another2 in fact1 that is where this recent colloquial use of the word originated4 ,iron ore is nothing more nor less than metallic iron1 the element1 chemically combined with oxygen1 another element which constitutes one-fifth of the air we breathe4 ,under conditions produced in the blast furnace1 though for centuries wedded to iron1 oxygen deserts him for her #8affinity' carbon1 which is best known to you as coke1 coal1 or charcoal4 ,the iron1 now free1 becomes molten at the high temperature encountered 7about #bhjj to #cjjj ,f47 and descends into the #8hearth' or bottom of the furnace1 while oxygen and her new partner escape out of the top of the furnace in gaseous form4 ,when molten iron has accumulated in the hearth to the extent desired it is tapped out as you will soon see4 ,illustration3 ,,diagrammatic ,,sketch ,,of ,,blast ,,furnace 8,the limestone charged has #8affinity' for dirt and certain other impurities of the ore which it removes in molten form as the #8cinder' or #8slag' which is there running into the ladle4 ,when cold1 this cinder is a dark greenish-black1 glassy substance1 which of recent years has come to be used to a certain extent in the manufacture of ,portland cement but is mainly used for filling-in purposes4 ,some is crushed and utilized in concrete mixtures and for road building4 ,in ,chicago considerable land has been #8made' by dumping slag into the lake1 and ,south ,chicago is reported as standing on a swamp which has been filled in with slag from the steel works there4 ,illustration3 ,,old-,,fashioned ,,pig ,,bed 8,this immense furnace is simply a strong steel shell lined two or three feet thick with fire bricks4 ,at the #8bosh1' which is the region where the greatest heat is produced1 hollow bronze plates are inserted among the bricks of the lining through which circulating cold water keeps the bricks from being fused4 8,the hot gases which are led from the upper part of the furnace through that brick-lined #8downcomer' are burning in three of those #8stoves' to heat them1 while cold1 clean air from the blowing engines is coming through the other stove1 which1 ten minutes ago1 when it was put on blast1 was the hottest of the four4 ,it is now giving up part of its accumulated heat to the blast on its way to the furnace4 ,switching the cold incoming air every little while from a partially cooled stove through a hotter one while allowing the former to reheat1 provides continuous blast of a temperature of #hjj to #adjj ,f4 ,the #8hot blast' idea originated about #ahcj with ,james ,neilson1 a gas engineer of ,england1 and its introduction revolutionized the blast furnace industry and made the highly efficient modern practice possible4 ,illustration3 ,,furnace ,,and ,,sand ,,bed ,,ready ,,for ,,iron 8,this big pipe above our heads which encircles the furnace is the #8bustle pipe4' ,it also has to be lined with fire bricks4 ,the hot blast is distributed by this #8bustle pipe' to the tuyres here--these ,l-shaped pipes--which shoot it directly into the furnace4 ,through the peep-holes in the tuyres you can get a glimpse of the dazzling interior of the furnace4 ,the blast of heated air is causing the coke to burn fiercely there so that it melts the iron1 which farther up in the furnace has been forced to part from the oxygen1 as ,i explained to you40 ,illustration3 ,,layout ,,of ,,blast ,,furnace ,,plant ,but now six men with a long steel bar are starting to break through the two or three feet of clay with which the 8tap hole0 of the monster furnace is plugged1 and our informant hurries away4 ,illustration3 ,,skip ,,hoist ,,at ,,work4 ,,skip ,,dumping ,,into ,,hopper ,for ten minutes with strong sledge blows the tappers struggle to break through the plug of burned clay4 ,meanwhile the monotonous whistle of the heavy blast into and through the bustle pipe and tuyres goes on and the discharge pipes of the water-cooling plates empty into the gutter around the furnace bottom the water which has been circulating to keep the inner bricks from fusing4 ,illustration3 ,,section ,,of ,,blast ,,furnace ,,showing ,,filling ,,arrangement1 ,,bins ,,and ,,ore ,,bridge ,and now a shout and the strong red glow throughout the cast house tell us that the tap hole is open and the iron is running down the main channel of the sand bed4 ,past the plugged entrances to the lateral branches runs the molten iron stream to the end of the cast house nearly one hundred feet distant where it divides1 filling the laterals on each side and from them running into many open molds arranged like the teeth of a comb4 ,each of these molds is about five feet long4 ,they form the 8pigs10 and the laterals what are known as 8sows40 ,as each lateral and its molds fill1 the lateral ahead of it is opened and the process repeated1 laterals and pigs filling up simultaneously on opposite sides of the main channel till the whole cast house floor is filled nearly up to the furnace with the red smoking metal4 ,illustration3 ,,sand ,,cast ,,pig ,,iron ,there are few sights more glorious than the cast house with bed just filling with metal1 and especially is it so at night4 ,the strong yellow-red light of the flaming metal issuing from the furnace and the intense glow of that already in the bed illuminates everything in and about the building4 ,but already1 before the furnace is empty1 the workmen are spraying with water the earliest cast pigs4 ,covering them with a light layer of sand they venture upon them with thick-soled shoes and break the 8pigs0 from the 8sows0 with sledge hammers4 ,this is the old-fashioned 8sand cast0 pig iron4 ,after remelting in the cupola furnaces of neighboring towns and casting into stove parts or other forms it is known as 8cast iron02 through 8puddling0 in reverberatory or special furnaces it becomes 8wrought iron02 after decarbonizing treatment in steel furnaces of various design it is changed into the wonderful material called 8steel40 ,pig iron is thus the intermediate or semi-raw material from which practically all of our various iron and steel products are made and the transition product through which they pass4 ,illustration3 ,,machine ,,cast ,,pig ,,iron ,but the romantic period of the hand-fed furnace and the gloriously beautiful pig beds at casting time are rapidly passing2 in fact1 are almost past4 ,modern 8skip-hoists0 carrying automatically dumped buckets or cars charge the furnace more economically than even low-waged laborers can do it4 ,the two charging cars alternate1 one filling at the bottom in the stock house while the other is dumping through the double bell at the top of the furnace4 ,furnaces are now tapped by power driven drills which make quick work of a formerly difficult operation4 ,instead of running it into the sand bed1 the molten iron from the furnace is nowadays run into ladles alongside the cast house as is the cinder which was described above4 ,if the metal is to be made into pigs it goes to the pig casting machine1 where the traveling iron molds very quickly convert the entire cast into 8chilled cast0 pigs4 ,at the top of the incline these pigs which have been cooling under sprays of water fall from the traveling molds into railroad cars below which deliver them to the consumer4 ,illustration3 ,,how ,,pig ,,iron ,,is ,,now ,,cast ,,into ,,traveling ,,molds ,illustration3 ,,upper ,,end ,,of ,,casting ,,machine ,,where ,,pigs ,,are ,,dumped ,,from ,,traveling ,,molds ,,into ,,railway ,,cars ,in large steel works the greater part of the molten iron is not cast into pigs at all but while yet molten is directly charged into the open-hearth or ,bessemer furnaces which convert it at once into steel of which the greater part is made into plate1 rails1 or other shapes before being allowed to cool4 ,even the gas is recovered nowadays4 ,its journey through the 8dust arrester0 rids it of most of its dust1 after which filters and washers clean it thoroughly4 ,that not required for the heating of the stoves is used for firing the steam boilers about the plant and as fuel for batteries of huge gas engines which in large plants have been installed to generate low-priced electric current4 ,it should be noted that in modern practice iron is mined1 loaded1 transported to the furnaces1 unloaded1 charged and made into pigs or converted into steel and even into the finished products with practically no hand labor1 all operations being performed by machinery4 ,though a 8direct0 process for converting the ore into wrought iron or steel has been long sought1 a method has never been found1 except that used in the very small way followed by the old iron-workers with their crude furnaces4 ,it has always proved commercially advantageous to make pig iron in the blast furnace as an intermediate step and then by a second step convert it into wrought iron1 steel1 etc4 ,so the ore is brought from the mines to the furnace1 the coke and limestone arrive from another region1 and batteries of huge blast furnaces through the country make from them the pig iron4 ,,blast ,,furnace ,,data ,,and ,,annual ,,pig ,,iron ,,production ,year ,average ,average ,average ,tons ,pig ,iron ,produced ,during ,height#a ,cu4 ,ft4 ,daily ,year of ,blast ,capacity ,output in ,furnace of ,blast ,tons ,each ,furnace ,united ,great ,germany ,states ,britain and ,luxemberg #ahej #cj #bjjj #bi #efe1jjj #ahfj #ibj1jjj #ahgj #a1hfe1jjj #e1ifc1jjj #a1cia1jjj #ahhj #gj #hbjj #aag #c1hce1jjj #g1gdi1jjj #b1gbi1jjj #ahij #ij #ahbjj #cfj #i1jjj1jjj #g1ijd1jjj #d1feh1jjj #aijj #ajj #bdjjj #fjjac1gij1jjj #i1jjc1jjj #g1eej1jjj #aije #ij to #ajj #bdjjj #fjjbc1jjj1jjj #i1gdf1jjjaj1ihh1jjj #aiaj #ij to #ajj #bdjjj #fjjbg1cjj1jjjaj1chj1jjjad1die1jjj #aiab #ij to #ajj #bdjjj #fjjcj1jjj1jjj #i1jcg1jjjag1hfi1jjj #aiac #ij to #ajj #bdjjj #fjjca1jjj1jjjaj1fed1jjjai1bib1jjj ,footnote #a3 ,no advantage has been found in furnaces having a height of over #aaj feet4 ,the chemical laboratory plays a very important rle in iron making4 ,analyses made of each car or boat load of ore by the furnace chemists representing the buyer must check very closely the analyses made by the mine chemists for the seller1 as the price of every ton of ore is based on its iron and its phosphorus contents and the percentages of certain other constituents present4 ,in calculating the 8burden0 or charges for the furnace1 each of these constituents is estimated in pounds actually present per charge1 losses or gains during the journey through the furnace are allowed for1 and by combining the various ores the charges are so made up that the resulting iron will be of certain desired composition4 ,the closeness of actual composition obtained to calculated results is startling4 ,truly this is an age of efficiency4 ,though technical information and statistics are not to be inflicted upon our readers to any extent in this series of articles1 it may not be amiss to give one table of interesting figures which show the increase in height and capacity of furnaces from #ahej to the present time4 ,during this period the annual production of pig iron in the ,united ,states has risen from #efe1jjj to #ca1jjj1jjj long tons 7#bbdj pounds74 ,it will be noted that since #ahhg1 when we passed ,great ,britain1 the ,united ,states has been the champion pig iron producer of the world4 ,the record production of a single blast furnace to date was that of one of the ,united ,states ,steel ,corporation's furnaces at ,duquesne1 ,penn41 which produced #ijj tons of pig iron in one day4 ,,chapter ,v ,a ,,general ,,glimpse ,,ahead ,we have arrived at the parting of the ways4 ,from the vast beds of iron ore1 the coal fields and coke ovens1 and from the quarries of limestone1 all roads have led to the blast furnace4 ,this we have visited and we now know how pig iron is made4 ,from this point the several paths diverge4 ,one by one we are to follow them to get acquainted with the interesting country which they traverse and the regions to which they lead4 ,however1 before choosing any one of these paths for our first trip1 it will be to our advantage to pause1 to study for a moment our position and get a general view of the country ahead of us4 ,we should know the relative locations and importance of the places we are going to visit1 for only by getting a comprehensive idea of the general plan of this ferrous 7meaning iron7 world1 can we understand to the best advantage the position of each of the main products1 wrought iron1 steel1 cast iron1 malleable iron1 etc41 and acquire a satisfactory knowledge of them4 ,in the last chapter pig iron was called the intermediate stage between the ore and the finished iron product1 and such the sketch given shows it to be4 ,it is only as an intermediate product that pig iron has value1 for nowhere in the commercial world has it a purpose except as a material to be chemically and structurally transformed into other materials which may themselves be used without further transformation4 ,it is desirable that we fully realize the position of this very important semi-raw material1 pig iron1 before passing on to the study1 one at a time1 of the refined ferrous products which are susceptible of direct use in our commercial life4 ,illustration3 ,,electric ,,arc1 ,,microscope1 ,,and ,,camera1 ,,part ,,of ,,metallographic ,,apparatus ,from ,table ,a 7page #ga7 it will be seen that from blast furnace metal several well-known products are formed by the various processes of refinement4 ,each of these methods of purification may be said to result in a certain general composition and structure which give to the material formed its character and properties4 ,the ,metallographic ,method of ,classification ,by aid of the microscope it is possible actually to look into the structure of these materials4 ,,table ,a ,,iron ,,and ,,steel ,,production ,,of ,,the ,,united ,,states ,,for #aiab #cjjj ,furnaces4 ,bar ,iron1 ,sheets4 ,,wrought ,,iron4 ,pipe1 ,boiler ,tubes1 #a1fcg1ehb tons ,stay ,bolts4 ,stock for 7#gej1jjj tons ,pig ,cementation and ,iron used74 ,crucible ,steel4 #ajb ,plants4 ,rails1 ,axles1 ,rods1 ,,bessemer ,,steel4 ,wire1 ,nails4 #a1cbg1ijj tons ,structural ,shapes4 7#aa1jjj1jjj tons ,pig ,pipe1 ,bar ,steel1 used74 ,steel ,castings4 #gh ,plants4 ,,acid ,,open-,,hearth ,rails1 ,plate1 ,axles4 ,,steel4 ,steel ,castings4 #a1aci1bba tons ,miscellaneous4 7#ejj1jjj tons ,pig used74 #ajj ,plants4 ,,basic ,rails1 ,plate1 ,axles1 ,,iron ,,ore ,,open-,,hearth ,,steel4 ,rods4 ,structural #ei1ige1jjj #ai1fda1ejb tons ,shapes4 ,pipe1 ,boiler ,,tons 7#aa1ejj1jjj tons ,pig ,tubes1 ,bar ,steel1 used74 ,steel ,castings4 ,stove1 ,radiator1 #dff ,,blast ,machinery ,parts1 ,,coke ,,used ,,furnaces ,,cast ,,iron4 ,valves1 ,pipe #ce1dia1bib ,,pig ,,iron #f1gej1jjj tons ,fittings1 etc41 ,bath ,,tons ,,made 7#e1jjj1jjj tons ,pig ,tubs1 ,sinks1 #bi1gbf1icg used74 ,carwheels1 ,,tons ,brakeshoes1 ,rolls1 ,misc4 ,castings4 ,railway ,car and ,,charcoal ,,malleable ,,iron4 ,agricultural #ce1dcf1jag #a1jjj1jjj tons ,machinery ,castings1 ,,bushels 7#gej1jjj tons ,pig ,pipe ,fittings1 used74 ,miscellaneous ,castings4 ,,limestone #ajh ,plants4 ,tool ,steels1 ,ordnance #ae1jib1aff ,,crucible ,,steel4 ,materials1 ,bar ,steel1 ,,tons #aba1eag tons4 ,castings4 #ad ,plants4 ,rails1 ,bar ,steel1 ,,electric ,,steel4 ,castings4 #ah1cji tons4 #d ,plants4 ,,other ,,steel ,tool ,steels1 ,bar ,,processes4 ,steel1 ,miscellaneous4 #bhec tons4 99 ,figures for ,pig ,iron ,used are ,estimates1 no ,conclusive ,statistics being available4 ,illustration3 ,,part ,,of ,a ,,chemical ,,laboratory ,,where #f1jjj ,,samples ,a ,,year ,,are ,,analyzed ,by cutting in any direction through a piece of metal or alloy1 polishing the surface exposed very clean and smooth and then etching 7corroding7 slightly with acid1 the exposed grains of the metal may be seen when sufficiently magnified4 ,not only may the grains of metal be seen1 but certain of the other constituents which are present are visible4 ,photographs1 also1 can be taken by attaching a camera to the microscope4 ,this method of analysis1 which is known as 8metallography10 has proved as valuable an aid to the metallurgist as it proved to the geologist when applied to the study of rocks and geological specimens4 ,illustration3 ,,machine ,,for ,,determining ,,strength ,,of ,,iron ,,and ,,steel ,,bars ,the metallography of wrought iron1 cast iron1 malleable iron and steel differentiates them to us with considerable accuracy1 as is shown by a glance at the accompanying photomicrographs1 as photographs taken through the microscope are called4 ,for our immediate purpose of gaining a general knowledge of the relative positions of these products1 this method of analysis probably cannot be excelled4 ,after the processes of manufacture of these materials have been taken up one by one in later chapters1 the photomicrographs will be even better understood than now1 as will the differences of chemical composition and physical properties of the alloys1 such as strength1 hardness1 brittleness1 forging quality1 etc4 ,the photomicrographs are given at this time to show that the materials are structurally very different and to aid in the general classification4 ,to make them comparative1 all have been taken at the same magnification of seventy diameters2 i4e41 the microscope has made everything shown just seventy times as large as it actually was in the alloy4 ,illustration3 ,no4 #aih4 ,,photomicrograph ,,of ,,sand ,,cast ,,pig ,,iron4 ,,the ,,thick ,,black ,,lines ,,are ,,graphite ,,flakes ,as stated before1 the alloy pig iron normally contains from #c to #e per cent of carbon4 ,this was absorbed during the journey through the blast furnace4 ,as long as the iron was molten all of this carbon was in the 8combined0 form2 i4e41 in chemical combination with the iron itself4 ,cold iron1 however1 cannot retain in the chemically combined form as much carbon as does molten iron1 so1 during the solidification and cooling of the alloy1 more or less of its carbon was precipitated1 i4e41 thrown out of solution and from chemical combination with the iron1 the amount depending mainly upon the speed of the cooling4 ,it appeared then as the 8free0 carbon 7crystalline graphite7 which remained distributed throughout the alloy and may be seen as the jet black flakes in photomicrograph ,no4 #aih4 ,every pure metal is supposed to be composed of crystals or grains which would have been of the true cubic form if the severe internal pressure during solidification and cooling had not distorted them4 ,photomicrograph ,no4 #ii;b represents quite well a pure metal4 ,it is that of an extremely mild steel made by special methods in the open-hearth steel furnace4 ,it is so highly refined that it can hardly be called steel at all but is often called 8open-hearth iron0 or 8ingot iron40 ,it is probably the purest iron on the market in commercial quantities to-day4 ,while in the chemical laboratory iron of considerably greater purity can be made1 for a commercial product this is remarkably pure1 seldom containing more than per cent of elements other than the metal1 iron4 ,illustration3 ,no4 #ii;b4 ,,open-,,hearth ,,iron4 ,,probably ,,the ,,purest ,,commercial ,,iron ,,product ,the boundary lines of the crystals or grains may be plainly seen4 ,each grain should show practically white4 ,the dark parallel lines1 the dots1 and the grayish portions result from inequalities in the polishing and etching4 ,illustration3 ,no4 #a;d4 ,,section ,,of ,,wrought ,,iron ,,cut ,,lengthwise ,,of ,,the ,,bar4 ,,black ,,patches ,,and ,,filaments ,,are 8,,slag0 ,,or 8,,cinder0 ,after noting the appearance of photomicrograph ,no4 #ii;b1 which is of a nearly pure iron1 one need have no difficulty in realizing that pig iron and the steels are alloys and not simple metals4 ,the truth is that of all alloys some of the well-known iron products which we are studying are by far the most complicated1 much more so than are the nonferrous alloys1 which include the brasses1 bronzes1 babbitts1 ,german silver1 etc4 ,illustration3 ,,physical ,,test ,,room ,,where #ae1jjj ,,specimens ,,are ,,tested ,,each ,,year ,this should not worry us1 however1 for we shall not attempt to follow them into their complications4 ,illustration3 ,no4 #c;b4 ,,steel ,,containing 4#aj ,,per ,,cent ,,of ,,carbon4 ,,the ,,carbon ,,is ,,in ,,the ,,black ,,patches ,the important point just now is to observe the crooked black flakes of crystalline graphite in this photomicrograph ,no4 #aih4 ,it is largely because of these flakes of brittle1 soft graphite that pig iron and the cast irons are so fragile4 ,one has no difficulty in realizing that these flakes1 which cut in every direction through the metal1 make it structurally weak1 especially toward a sudden blow4 ,no4 #a;d shows a typical section of wrought iron cut lengthwise of the rolled bar4 ,it will be noted that1 as in photomicrograph ,no4 #ii;b1 there are no graphite flakes4 ,in the process of wrought iron manufacture practically all of the carbon of the original pig iron is burned out1 leaving little besides the iron itself and some viscous cinder or slag4 ,in the rolling or hammering out of the resulting white-hot 8bloom10 the slag enclosures which remain after the squeezing process are extended lengthwise through the bar4 ,upon observing with the microscope any prepared section of wrought iron which has been cut lengthwise of the bar the filaments of slag may be plainly seen1 all parallel or practically so4 ,when such filaments of slag can be discerned in a longitudinal section it is practically an absolute indication that the material in question is wrought iron4 ,illustration3 ,no4 #bb;c4 ,,steel ,,with 4#ej ,,per ,,cent ,,of ,,carbon ,illustration3 ,no4 #cf;a4 ,,steel ,,with #a4ih ,,per ,,cent ,,of ,,carbon ,photomicrograph ,no4 #c;b is that of mild steel containing 4#aj per cent 7 per cent7 of carbon4 ,here we have neither the graphite flakes of ,no4 #aih nor the slag filaments of ,no4 #a;d4 ,we can plainly see the boundary lines of the grains4 ,the irregular dark patches which are evenly distributed throughout are the defining features of steel4 ,in what might be called a chemical-mechanical combination1 these dark patches contain all of the small percentage of carbon which gives to carbon steel its definite properties4 ,during the manufacture of this alloy all but a small amount of carbon is eliminated by burning it out1 as happens with wrought iron4 ,but the steel is molten or fluid when finished and the slag which has been formed floats on top and is also eliminated1 which does not occur with wrought iron1 which is thick and pasty at its finishing temperature4 ,illustration3 ,no4 #gd4 ,,gray ,,cast ,,iron4 ,,the ,,crooked ,,black ,,lines ,,are ,,graphite ,,flakes ,therefore1 steel contains no graphite and no slag but has only the small percentage of carbon which was purposely put back to give to it its valuable properties4 ,illustration3 ,no4 #ib;d4 ,,semi-,,steel1 ,a ,,stronger ,,gray ,,cast ,,iron ,photomicrograph ,no4 #bb;c is typical for steel which contains 4#ej per cent 7 per cent7 of carbon4 ,the irregular patches containing the carbon are much larger and more frequent4 ,it will be seen1 therefore1 that through metallography the various iron alloys1 to a considerable extent1 may be analyzed as well as classified4 ,photomicrographs ,nos4 #gd and #ib;d represent soft and stronger grades of ordinary gray cast iron respectively4 ,it will be noted at once that both much resemble pig iron in structure1 as of course they should1 for simple remelting in the cupola does not effect much modification in composition or structure4 ,occasionally castings are made from molten iron direct from the blast furnace1 but such practice is not very satisfactory and is little done4 ,it forms probably the only exception to the statement made above that pig iron has no useful purpose in the commercial world except as something to be transformed by some refining process into another material4 ,illustration3 ,no4 #acb4 ,,gray ,,cast ,,iron #bjj ,,years ,,old ,illustration3 ,no4 #aji4 ,,malleable ,,cast ,,iron ,,before ,,annealing ,the remelting for the well-known cast iron is usually of such selected brands of pig iron and cast scrap as will produce cast iron best adapted to the purposes intended4 ,the resulting alloy still contains #c per cent or #c per cent of carbon4 ,no4 #acb is interesting4 ,it is a photomicrograph of a piece of cast iron which is approximately #bjj years old4 ,from the standpoint of the metallurgist it is the same as other photomicrographs of cast iron1 the difference in appearance resulting probably from casting conditions1 etc4 ,malleable cast iron is made much as is gray cast iron except that it is brought to such a composition that sections of castings made from the melt show a white fracture when broken4 ,castings of gray iron of course show a gray fracture4 ,the former are extremely hard and are as brittle as glass until they have gone through a careful long anneal or heat softening process4 ,by maintaining them at cherry-red heat away from air for sixty hours or more and cooling slowly1 they become 8malleable02 i4e41 not brittle at all but capable of considerable distortion without cracking4 ,illustration3 ,no4 #ce4 ,,malleable ,,cast ,,iron ,,annealed ,from the viewpoint of malleability1 malleable iron may be considered to occupy a position between gray cast iron and steel4 ,photomicrographs ,nos4 #aji and #ce are those of malleable iron before and after the annealing treatment4 ,the former shows the typical structure of white cast iron1 while the latter plainly shows the minute lumps of pure carbon and the surrounding grains of pure iron metal1 the two having become divorced through the annealing process4 ,note that the large amount of carbon in this1 the 8temper carbon0 form1 does not make the alloy brittle through cutting of the grains as does the crystalline graphite form of carbon4 ,the above gives very briefly the most essential points in the classification of the irons and steels from the structural standpoint4 ,true it has not entered into the vast complications of the higher carbon or tool steels which are those which will take a 8temper02 i4e41 the tool steel's quality of hardening by quenching in water from a cherry red heat4 ,the simpler points of these will be taken up later4 ,but enough has been given that we now understand something of the relative positions of the great main products1 some reasons therefor1 and their general structures4 ,illustration3 ,,no4 #h4 ,,bar ,,rolled ,,from ,,scrap2 ,,contains ,,both ,,wrought ,,iron ,,and ,,steel ,it has been seen that their micrographs quite definitely differentiate them and probably no one will have difficulty in recognizing and naming such specimens4 ,as testing this it may be interesting to note photomicrograph ,no4 #h4 ,two different iron alloys made up the material from which this photomicrograph was taken4 ,apparently the bar was one made by heating and rolling together scrap metals4 ,such material is on the market4 ,the photomicrograph shows that some of the scrap used was wrought iron and some of it mild steel of about 4#jh carbon4 ,classification by ,chemical ,analysis and by ,physical ,tests ,so far not much has been said about composition except that upon it to a great extent depends the structure and physical properties of the alloy4 ,composition and physical characteristics as well as structures are necessary to a fair ,,table ,b--,,chemical ,,composition ,,and ,,physical ,,properties ,per ,per ,cent ,per ,per ,beginning ,tensile ,cent ,graphitic,cent ,cent of ,strength#c ,silicon ,carbon ,total ,freezing#b ,carbon #a4 ,sand ,cast #b4ej #c4ge 4#be #d4jj #bajj ,pig ,iron #b4 ,machine #b4ej #c4jja4jj #d4jj #bajj ,cast ,pig ,iron #c4 ,open-,hearth 4#jc 4#jj 4#jb 4#jb #bgdj #ej1jjj ,iron #d4 ,wrought ,slag 4#jj 4#je 4#je #bgdj #eb1jjj ,iron #e4 ,mild ,steel 4#je 4#jj 4#aj 4#aj #bgdj #ee1jjj #f4 ,medium 4#je 4#jj 4#be 4#be #bgbj #fe1jjj ,steel #g4 ,rail ,steel 4#je 4#jj 4#fj 4#fj #bfhj #ij1jjj #h4 ,low ,carbon 4#ae 4#jj 4#ge 4#ge #bffj #ajj1jjj ,tool ,steel #i4 ,medium 4#ae 4#jja4jj #a4jj #bfcj #abj1jjj ,carbon ,tool ,steel #aj4 ,high ,carbon 4#ae 4#jja4be #a4be #bfjj #ace1jjj ,tool ,steel #aa4 ,very ,high 4#ae 4#jja4ej #a4ej #befj #abd1jjj ,carbon ,tool ,steel #ab4 ,high ,steel 4#jja4ge #a4ge #becj #ac4 ,white ,iron 4#jjb4ej #b4ej #bdfj #ad4 ,white ,cast 4#gj 4#ajb4fe #b4ge #bdjj #da1jjj ,iron #ae4 ,annealed 4#gj #b4gj 4#je #b4ge #dj1jjj ,malleable ,cast ,iron #af4 ,cast ,iron #a4jj #a4jjb4jj #c4jj #bccj #ce1jjj for ,chilled ,castings #ag4 ,semi-,steel #a4ge #b4hj 4#dj #c4bj #bcjj #ce1jjj #ah4 ,gray ,cast #b4jj #c4aj 4#cj #c4dj #bbjj #be1jjj ,iron #ai4 ,soft ,gray #b4ej #c4cj 4#ae #c4de #bbjj #bc1jjj ,cast ,iron ,elongation#d ,welding ,principal ,uses ,properties #a4 ,sand ,cast ,further ,refining4 ,pig ,iron #b4 ,machine ,further ,refining4 ,cast ,pig ,iron #c4 ,open-,hearth#b ,good ,bars1 pipe1 ,iron sheet4 #d4 ,wrought #b ,fine ,bars1 pipe1 ,iron boiler tubes1 stay bolts4 #e4 ,mild ,steel #b ,good ,bars1 pipe1 wire1 sheet1 shafting1 tubes4 #f4 ,medium #b ,good ,bars1 plate1 ,steel structural4 #g4 ,rail ,steel #a ,fair ,rails1 gears4 #h4 ,low ,carbon #a ,fair ,hammers1 cold ,tool chisels1 saws1 ,steel springs4 #i4 ,medium #a ,poor ,lathe tools1 ,carbon chisels1 ,tool drills1 dies1 ,steel springs4 #aj4 ,high ,carbon#a ,slight ,lathe tools1 ,tool chisels1 files1 ,steel saws4 #aa4 ,very ,high ,slight ,razors1 lancets1 ,carbon graving tools1 ,tool saws for steel4 ,steel #ab4 ,high ,steel #j ,none ,dies for wire drawing4 #ac4 ,white ,iron #j ,none ,dies for wire drawing4 #ad4 ,white ,cast #j ,none ,for ,iron malleableizing1 carwheels4 #ae4 ,annealed ,none ,railway and ,malleable agricultural ,cast ,iron castings1 fittings4 #af4 ,cast ,iron #j ,none ,rolls1 gears1 for brakeshoes4 ,chilled ,castings #ag4 ,semi-,steel #j ,none ,gears1 steam cylinders1 valves4 #ah4 ,gray ,cast #j ,none ,machine parts1 ,iron grates1 radiators1 valves1 soil pipe4 #ai4 ,soft ,gray #j ,none ,stoves1 ,cast ,iron hollowware1 pipe fittings1 misc4 ,footnote #b3 ,in degrees ,fahrenheit4 ,for our purposes1 the same as the melting points of the alloys4 ,footnote #c3 ,pounds required to pull apart lengthwise a bar one inch square4 ,footnote #d3 ,number of inches that a bar eight inches long will stretch before it breaks4 ,illustration3 ,,iron ,,and ,,steel ,,test ,,pieces ,,and ,,instruments ,,used ,,in ,,measuring ,,their ,,size1 ,,elastic ,,limit ,,and ,,elongation understanding of the subject4 ,there is given therefore1 a table showing approximate comparative values of chemical compositions and physical properties of the alloys under discussion4 ,it should be distinctly understood that the figures given in ,table ,b are approximate only and are intended to be average1 or rather1 perhaps1 typical4 ,there are all sorts of conditions which in practice modify the figures given in the table1 and criticism may be maintained justly against some of the too specific statements which here it was necessary to make4 ,the classification is given with considerable hesitation and only because1 arranged in this way1 it brings out existing relationships which otherwise would escape notice and which we cannot afford to overlook4 ,but please do not gain the impression that these alloys are divided into distinct classes4 ,there are no dividing lines at all4 ,one group merges into the next so gradually that it is impossible to tell where the one ends and the other begins4 ,it is to be hoped that no one will make himself miserable by trying to digest these rather formidable figures of ,table ,b all at one sitting4 ,they are given mainly for comparison and for reference4 ,it is suggested that after noting carefully the similarities and differences to which attention is called1 they be reserved until the processes of manufacture of the various alloys are taken up one by one4 ,reference to these figures on those occasions should be profitable4 ,the main points to be noted at this time are3 #a4 ,open-hearth iron is practically pure iron1 having no constituents or slag inclusions which materially affect its properties4 #b4 ,wrought iron1 for all practical purposes1 is pure iron except for its content of slag4 ,it is the only one of the iron family which does normally contain slag4 #c4 ,neither open-hearth iron nor wrought iron contains carbon in appreciable quantities4 #d4 ,the distinguishing and active element of the steel family is carbon4 ,with increase of carbon the hardness of the alloy increases as does its tensile strength1 but the ductility 7elongation or stretch7 decreases4 #e4 ,other conditions being equal1 the more carbon the alloy contains the more easily it melts2 i4e41 at lower temperature4 ,so the purer irons such as open-hearth iron1 wrought iron1 and mild steel 7i4e41 steel with low carbon1 usually under #j4ae per cent7 have relatively high and the cast irons lower melting points4 ,,table ,c--,,percentages ,,of ,,the ,,so-,,called 8,,metalloids0 ,,by ,,weight ,,and ,,by ,,volume ,silicon ,manganese ,sulphur ,phosphorus ,wt4 ,vol4 ,wt4 ,vol4 ,wt4,vol4 ,wt4 ,vol4 ,gray ,cast ,iron #b4ejaj4j 4#gj 4#g4ji4cf 4#gec4b ,semi-,steel #a4ge #g4ja4jja4j4aj4dj 4#cea4e ,malleable ,cast ,iron 4#gj #b4h 4#ej 4#e4ae4fj 4#ag 4#g ,cast ,steel 4#cj #a4b 4#ej 4#e4je4bj 4#jd4ag ,mild ,steel 4#je 4#b 4#dj 4#d4jd4af 4#jc4ac ,open-hearth ,iron 4#jc 4#a 4#jb4jb4ja4jf 4#ja4jf ,wrought ,iron #a4bj #e4j 4#jh4jh4ja4jd 4#ae4fe ,total ,iron#e ,total ,carbon ,metalloids ,wt4 ,vol4 ,wt4 ,wt4 ,vol4 ,gray ,cast ,iron #c4deab4a #ib4e #g4ebf4d ,semi-,steel #c4bjaa4b #ic4f #f4dba4a ,malleable ,cast ,iron#b4ge #i4f #ie4g #d4cad4c ,cast ,steel 4#ce #a4b #ih4h #a4b #c4c ,mild ,steel 4#aj 4#ce #ii4d 4#f #a4b ,open-hearth ,iron 4#jb 4#jg #ii4i 4#a 4#c ,wrought ,iron 4#je 4#ag #ig4g #b4c #e4i ,footnote #e3 ,these alloys contain small amounts of other elements so these percentages of iron are a little high1 though approximately correct4 ,note the purity 7high percentage of iron7 of the open-hearth iron4 #f4 ,in the cast irons1 the carbon occurs not in one only but in two different forms2 i4e41 as graphitic carbon1 commonly called graphite 7,gr4 ,c47 and the combined form 7,c4 ,c474 ,the sum of these is usually between #c4jj per cent and #c4ej per cent4 ,it is not so much the total amount of the carbon that causes the differences in structure and physical properties which have been noted in #a and #b and in #af and #ag above1 as it is the relative proportions in which these two varieties occur4 ,illustration3 ,,exhibition ,,case ,,showing ,,four ,,well-,,known ,,iron ,,alloys ,,with ,,their ,,metalloids #g4 ,no one knows just when1 with increase of carbon1 steel ceases to be steel and becomes white cast iron4 ,there is no definite dividing line either in chemical or physical properties4 ,the changes are extremely gradual throughout the scale4 ,aided by the microscope1 modern physical chemistry has disclosed the fact that alloys of iron with carbon 8freeze0 from molten to solid condition according to two different laws4 ,the change from one to the other occurs somewhere between #a4g per cent and #b4b per cent of carbon as is described in ,chapter ,,xxii4 ,this is our only basis for calling alloys with less than #b per cent of carbon1 steels1 and those with greater amounts1 cast irons4 #h4 ,for our immediate purposes the other 8metalloids0 or constituents are of secondary importance and will not be taken up now4 ,from this it must not be understood that they can be slighted by the metallurgist and furnace man in his work4 ,they cannot4 ,every one of them is of importance and must be accounted for in the final product or trouble results4 ,volumetric ,analysis of the ,iron ,alloys ,there is a way in which we may visually get a very intimate idea of the relative composition of these alloys4 ,the cabinet of which a photograph is given is partitioned into four sections4 ,each one of these contains a bar and six specimen jars4 ,as you may or may not be able to read from the labels1 the bars1 all of exactly the same size1 are soft cast iron1 semi-steel 7a stronger cast iron71 annealed malleable iron and cast steel4 ,the six jars above each bar contain the exact amounts of the various constituents other than iron which are in the bar beneath4 ,as none of the constituents except manganese are as heavy as iron1 their volumes per unit of weight are correspondingly greater4 ,putting it into approximate figures we have the percentages by weight and by volume shown in ,table ,c4 ,this means1 of course1 that of the cast iron plates of your cook stove or steam or water radiators fully one-quarter 7#bf per cent by volume7 is not iron at all but brittle substances of little or no strength4 ,these elements1 silicon1 sulphur1 phosphorus1 and carbon1 are commonly called 8metalloids40 ,while the first three named are not in 8free0 form in the alloy and therefore allow of some doubt as to just the space they require1 we have good reason to suppose that the figures given are not far from correct4 ,with such a volume of weakening constituents and particularly with the graphite flakes cutting through and separating the iron grains as the photomicrographs show1 can one wonder that cast iron is fragile--more so than steel or wrought iron8 ,to sum up1 naming only the most familiar alloys and the two or three qualifying features of each which stand forth with particular boldness1 we have3 ,pig ,iron--,very ,high ,carbon4 ,brittle4 ,gray ,cast ,iron--,high ,carbon4 ,brittle4 ,malleable ,cast ,iron--,high ,carbon4 ,made ,malleable by ,annealing4 ,wrought ,iron--,slag4 ,little or no ,carbon4 ,very ,malleable without ,annealing4 ,mild ,steel--,very ,low ,carbon4 ,no ,slag4 ,very ,malleable without ,annealing4 ,carbon ,tool ,steel--,medium ,carbon4 ,no ,slag4 ,of ,medium ,malleability4 ,so steel which is not called 8iron0 at all is a very pure metal in comparison with gray and malleable cast iron and usually has a larger percentage of the chemical element1 iron from which all are derived1 than has the well-known wrought iron itself4 ,,chapter ,,vi ,,wrought ,,iron ,we of ,america1 and especially of the ,west1 never have been particularly devoted to the study of our genealogies4 ,however1 it is likely that most of us at one time or other in our mind's eye have seen that little country town back in ,massachusetts or ,new ,york ,state1 whence came our forebears4 ,since those days of long ago1 when1 with you upon his knee1 grandfather waxed reminiscent and related tales of his boyhood1 haven't you many times wished that ,father ,time could carry you back with him a hundred and fifty years and allow you for a few hours to walk among those good people with their quaint dress and customs8 ,how interested you would be in the relatives and friends whose queerly transcribed verses1 bearing date of a century and a half ago1 adorn the yellow pages of your great aunt's autograph album1 which is one of your treasures6 ,to the present rather unsentimental world we admit of much the same sort of reverent feeling as we traverse the paths1 centuries old1 of the wrought iron region4 ,here is something which links us with the antiquities and we 8take off our hats and tread lightly0 over the lands and the centuries in and through which this primal material1 wrought iron1 has been produced4 ,but we come back to a plain statement of the case4 ,let not the fact be overlooked that it is wrought iron which in some form or other has been made during the forty or more centuries that iron has been known4 ,it undoubtedly was the pioneer of the iron family and through all of the centuries it has maintained its importance4 ,from it as a base during the earlier centuries were made the steels for which the ancients were so famous1 and similar practice has prevailed from those early times up to the present day4 ,illustration3 ,,wrought ,,iron ,,bar ,steel has no 8fiber0 and can not be split in this way4 ,we say that the iron made by the ancients was in reality a variety of what we now term wrought iron1 for it fulfilled three of the principal requirements for wrought iron1 viz41 it was not necessarily melted during production1 it was a malleable metal1 and it contained cinder or slag1 but practically no carbon4 ,early iron and steel1 of course1 were comparatively rare1 so much so as to be available only for implements of war and for particular purposes4 ,moreover1 all of the steel made was of the high carbon1 hard variety1 none of it being of the low carbon sort which we know as the soft or mild steels4 ,the latter have all come since the invention of the ,bessemer process in #ahee and the ,siemens-,martin 7the open-hearth7 process of a few years later4 ,as you will remember the next development in the iron industry was the use of the larger blast furnace and much more fuel1 with higher temperatures and the production of cast iron which1 by reason of the absorption of considerable carbon from the fuel1 was fluid enough to run out of the furnace4 ,and1 as you also know1 this blast furnace metal has come to be the great intermediate product in what has come to be known as the ,indirect ,process of making iron and steel4 ,illustration3 ,,pickling ,,in ,,weak ,,acid ,,exposes ,,the 8,,fibers0 ,,of ,,wrought ,,iron ,as pig iron contains #c or more of carbon1 while wrought iron has none or comparatively little of this embrittling element1 any process for converting the pig iron into wrought iron must eliminate the carbon4 ,following the advent of pig iron as a commercial product several furnaces and processes were developed to turn it into wrought iron4 ,all of these were based upon the elimination of the carbon by oxidation1 which means the burning of the carbon in presence of oxygen of the air4 ,the best known ones were the ,walloon or ,swedish ,lancashire process1 the ,south ,wales process1 the ,finery ,fire1 the ,running-,out ,fire and the ,charcoal ,finery or ,knobbling process4 ,the ,walloon furnace1 largely used in ,sweden1 is shown in the illustration on page #id4 ,while by the process generally used to-day wrought iron is more easily and cheaply produced1 it must be said that by the processes above named has been made as fine iron as has ever been produced4 ,the ,sheffield manufacturers1 whose high grade steel made by the crucible process1 is so widely and favorably known for cutlery1 tools1 etc41 in many cases yet demand the ,walloon process iron made from high grade ,swedish ores as the starting point for their product4 ,illustration3 ,,bar ,,iron ,,will ,,stand ,,severe ,,bending ,,even ,,after ,,it ,,has ,,been ,,nicked ,illustration3 ,,swedish ,,walloon ,,furnace ,one of several types of furnaces that preceded the ,reverberatory4 ,some of them are still used4 ,in these furnaces which consisted mainly of a shallow hearth filled with glowing charcoal1 with tuyres for blast supply1 the pigs of iron were heated until molten4 ,at high temperatures the metalloids of pig iron will readily burn in a blast of air4 ,after the air blown over and upon the molten metal has burned out most of the carbon1 the main metalloid1 the melting point of the purified metal becomes so much higher that the heat of the furnace is not sufficient to keep it molten4 ,it becomes more and more pasty and stiff therefore4 ,this is what the iron maker calls 8coming to nature40 ,it is the signal that the carbon is about gone and that he must be careful or the iron will suffer in quality4 ,at this stage he sees to it that the mass of pasty iron is well protected by glowing charcoal until it is removed to be hammered or worked into a bar4 ,this in general is the process which was used from about the fourteenth century up to #aghc when ,cort invented the reverberatory furnace which has since been the type generally used4 ,in the processes just referred to1 all very similar1 it should be noted that the iron was in contact with the fuel1 which1 therefore1 had to be charcoal1 the fuel with little or no sulphur4 ,illustration3 ,,cort',s ,,reverberatory ,,furnace ,this is the type of furnace generally used to-day4 ,charcoal was an expensive fuel1 and1 moreover1 there was an insufficient supply because of the great destruction of forests necessary for its production4 ,naturally the thing to do was to substitute coal1 which was plentiful4 ,but the sulphur of the coal spoiled the iron4 ,this proved to be a great barrier until #aghc when ,henry ,cort of ,england succeeded in making wrought iron in a new type of furnace wherein the iron was refined in one compartment while the fuel was made to furnish its heat from another2 i4 e41 the fuel and the metal were not in contact and the refined metal did not suffer from the sulphur content of the coal4 ,the figure illustrating ,cort's furnace plainly shows how this was accomplished and it represents almost as well the furnace used to-day4 ,in the one-hundred and thirty-three years that have elapsed since it was designed1 his furnace has been changed only in certain details1 and but two important changes have been made in his process--the use of an iron bottom instead of the sand bed by ,s4 ,b4 ,rogers in #ahjd and the introduction of 8pig boiling0 by ,joseph ,hall in #ahcj4 ,cort's process is known as 8dry puddling0 and his trouble was the excessive loss of iron1 due to his use of the sand bottom and the absence of a proper cinder4 ,the loss was said to have been from #ej to #gj of the iron charged2 i4 e41 it took about #b tons of pig iron to make one ton of wrought iron4 ,because of the great demand for iron and the fact that he was using such a cheap fuel1 coal1 his process at that time was a success financially4 ,illustration3 ,,early ,,iron ,,rolls ,while ,cort did not originate the idea1 it was he who first made the rolling process successful1 and1 therefore1 he is given credit for the invention4 ,but ,cort did not stop here4 ,he saw the desirability of a quicker and more economical method of reducing the 8blooms0 or balls of iron into bars or other finished shapes than the hammering process up to that time used4 ,he accomplished this by the use of power driven rolls1 such as those shown in the cut4 ,these two inventions of ,cort's were epoch making1 though of the two the more important one was the invention of the rolls from which has developed the modern rolling mill4 ,there remains to be described in a little more detail the making of wrought iron as practiced to-day4 ,the puddling furnace used has a grate upon which is built the coal fire4 ,the long flame passes over the fire wall and is deflected by the roof down upon the charge of pig iron piled upon the 8fettling0 or lining of iron oxide 7iron ore or mill scale7 over the air or water cooled iron plates which form the bottom and the sides of the hearth4 ,with a long iron bar the 8puddler0 7the expert attendant7 turns the pigs until they have melted down into the bath of slag or cinder charged and continually being formed by the chemical union of iron from the ore or pig and some of the sand and other impurities present4 ,this cinder1 which is largely a silicate of iron1 is a protection for the bath of molten iron and its use prevents excessive oxidation and loss of metal4 ,during the melting of the charge the heat is kept as high as possible and the molten iron is 8puddled10 i4 e41 stirred1 by the 8puddler0 or his helper with a 8rabbler0 or iron bar4 ,in order to take out the phosphorus and sulphur1 which for best results should be removed before the carbon is eliminated1 the heat of the furnace is lowered somewhat as soon as all of the pig has melted1 and some iron oxide is mixed into the 8bath0 of molten iron and cinder4 ,most of the phosphorus and sulphur are chemically acted upon and pass into the cinder which covers the iron4 ,soon the mass begins to boil or seethe and small blue flames break through the cinder covering4 ,this indicates that the carbon is being oxidized by the oxygen of the iron ore which was added1 the oxygen1 as in the blast furnace1 having a greater 8affinity0 for carbon than it has for the iron4 ,this 8pig boiling0 goes on for twenty or thirty minutes1 the 8puddler0 meanwhile 8rabbling0 the charge in order to hurry the reactions and to make sure that all parts of the bath of molten metal are uniformly exposed to the oxidizing conditions4 ,illustration3 ,,the ,,making ,,of ,,wrought ,,iron ,,to-,,day4 ,,charging ,,the ,,pig ,,iron ,soon the metal begins to 8come to nature0 and little lumps of pure iron here and there through the bath stiffen up into little pasty balls4 ,some may be seen sticking out through the cinder covering of the bath and others must be torn loose from the bottom with the rabbler4 ,this 8balling0 period lasts from fifteen to twenty minutes1 during which time all of the iron has 8come to nature40 ,illustration3 ,,the ,,coal ,,pile ,,and ,,fire ,,box ,,of ,a ,,reverberatory ,,furnace ,illustration3 ,,turning ,,the ,,pigs ,,to ,,insure ,,even ,,melting ,the puddler quickly separates into two or three white-hot balls the #djj pounds or so of spongy iron4 ,these balls1 full of and dripping with cinder1 are seized1 one at a time1 with long tongs1 removed from the furnace and rushed to the rotary squeezer through which they are twisted and turned1 ever becoming longer and smaller in diameter until they emerge from the other and narrower side much compacted and with but little of the cinder which they originally carried4 ,without being given time to cool1 the blooms are seized and shoved into the 8muck rolls10 whence after a few passes they emerge as long flat bars1 very rough and imperfect in appearance4 ,after shearing into short lengths1 many pieces of this 8muck bar10 as it is called1 are made into 8box piles0 and tied together with wires4 ,these are charged into the furnace of the finishing mill4 ,after coming to a white heat the box piles go to the finishing rolls where they are rolled into bars1 rods1 plates1 or other shapes desired4 ,by repeated cutting1 piling1 heating1 and rolling1 double refined and other high grades of wrought iron are made1 each repiling and rerolling1 of course1 producing a more compact and better product4 ,illustration3 ,,puddling ,,the ,,melted ,,charge ,illustration3 ,,considerable ,,cinder ,,overflows ,,during ,,the 8,,boiling0 ,,stage ,wrought iron has a 8fiber10 as may be seen from two of the illustrations presented4 ,in 8coming to nature0 small particles of iron crystallize out as they become purer4 ,these measure perhaps or in diameter4 ,as it goes to the squeezer the ball of 8sponge0 is made up of such grains of iron loosely welded together with the interstices filled with cinder4 ,the squeezer1 and later the rolls1 elongate the particles of iron into threads1 which1 welded together1 make the bar4 ,it is thought by some that films of cinder1 too thin to be seen under the microscope1 surround each fiber of iron and that these afford protection from rusting and give to wrought iron the excellent welding quality that it possesses4 ,illustration3 ,,drawing ,,one ,,of ,,the ,,balls ,,from ,,the ,,furnace ,illustration3 ,,on ,,the ,,way ,,to ,,the 8,,squeezer0 ,steel has no fiber and for this reason it cannot be split as was the wrought iron bar shown in the illustration of page #ib4 ,it will have been noticed that only small amounts of iron can be refined at one time4 ,this1 indeed1 has been the unfortunate part of wrought iron manufacture1 for it may readily be seen that production of any such material in lots as small as a quarter ton results in labor costs which are almost prohibitive in these days of machine-made goods4 ,not only is the output of a furnace small but much skill and judgment are necessary for the production of a high grade product4 ,very sturdy and strong men1 too1 are required as puddlers1 for the work is heavy and the extremes of heat and cold to which they are exposed necessitate men of rugged health4 ,illustration3 ,,cross-,,section ,,of ,a 8,,squeezer0 ,this material in bar iron1 engine stay bolts1 butt and lap-welded pipe and certain other products has long held a high place4 ,though not as strong as steel1 its very excellent welding properties and comparative freedom from 8crystallization0 and treacherous breakage under long continued vibration or sudden jar have fostered its application in such products as stay bolts1 chain-links1 cable hooks and others where failure might have serious consequences4 ,too1 it is thought by many that pipes1 sheets and other articles of wrought iron resist the corrosive influences of moist air1 soil1 etc41 particularly well4 ,the cinder films in which the fibers are supposed to be encased are given credit for such protective influence4 ,illustration3 8,,box ,,piles0 ,,ready ,,for ,,the ,,re-,,heating ,,furnace ,though the product has always been a favorite with iron users1 the industry has suffered during the last sixty years by reason of the high cost of manufacture1 which has very largely restricted the application of wrought iron to certain uses for which first cost is not a main factor4 ,the production of wrought iron rails has rapidly dwindled since the year #ahhj1 when they began generally to be replaced by rails made from ,bessemer steel4 ,illustration3 ,,the ,,ball ,,going ,,into ,,the 8,,squeezer0 ,illustration3 ,,shearing ,,the ,,muck ,,bar ,,into ,,short ,,lengths ,,for 8,,piling0 ,illustration3 ,,the ,,bloom ,,from ,,the ,,squeezer ,,goes ,,to ,,the 8,,muck0 ,,rolls ,,which ,,roll ,,it ,,down ,,into 8,,muck ,,bar0 ,illustration3 ,,the ,,re-,,heated 8,,box ,,piles0 ,,being ,,rolled ,,into 8,,skelp0 ,,for ,,pipe1 ,,in ,,the ,,finishing ,,mills ,illustration3 ,,cross ,,piling ,,gives ,,cross ,,fibers ,,in ,,the ,,finished ,,bar--,a ,,desirable ,,quality ,of recent years1 mild steel has been the great competitor of wrought iron4 ,with marvelous energy1 skill1 and much capital the manufacturers of ,bessemer and open-hearth steels have adapted their products very well to the needs of the iron user1 while the enormous tonnages turned out in short time by use of ingenious furnaces and other devices has resulted in a low cost of production4 ,had any of the several mechanical puddling furnaces devised for the manufacture of wrought iron proved really successful1 things might be more rosy commercially for this very excellent material4 ,according to the #aiaf ,statistical ,report of the ,american ,iron and ,steel ,institute1 the recent yearly production in this country of wrought iron and steel merchant bars1 plates and sheets1 and skelp for pipe in gross tons has been3 ,merchant ,bars ,plate and ,sheets ,skelp for ,pipe ,iron ,steel ,iron ,steel ,iron ,steel #aijea1cbb1dcib1bga1afb #gb1aefc1dfj1jgd #deb1gig #ihc1aih #aijfa1dha1cdhb1eaj1heb #gd1cgcd1ajg1ghc #cia1eaga1acg1jfh #aijga1ddj1cefb1ecj1fcb #gd1jchd1agd1gid #ddd1ecfa1ceh1jia #aijh #fhe1bcca1cja1dje #ed1jccb1eie1ffj #big1jdi #hec1ecd #aiji #ieb1bcjb1caa1cja #gf1bjbd1aeh1add #cgj1aeaa1ffc1bcj #aiaja1jgd1afcb1gaa1efh #ia1aahd1hfd1cff #cej1egha1dgg1faf #aiaa #hce1fbeb1baa1gcg #hi1dbgd1cih1fbb #cbb1ciga1feh1bgf #aiab #idd1gijb1geb1cbd #ge1jdde1hjj1jcf #cbg1jabb1aai1hjd #aiaca1jbf1fcbb1icj1igg #fd1gbie1fhf1cjh #cab1gdfb1ahi1bah #aiad #efc1agaa1ifj1dfj #ef1eijd1ffb1fef #bfd1cdja1gah1jia #aiae #feg1ajgc1dgd1ace #bj1becf1jeg1dda #bfb1aihb1jcg1bff #aiaf #iic1idhe1fbe1eih #ac1cjcg1ddj1fgg #cee1ddeb1egb1bbi ,there is considerable so-called wrought iron on the market to-day which is not truly wrought iron1 by which we mean iron 8puddled0 from pig iron4 ,bushelled ,iron ,after heating a mixture of thin sheet or other soft steel and wrought iron scrap to a welding heat in a reverberatory furnace1 it may be balled and put through the squeezer1 muck rolls1 etc41 as was the true wrought iron made by puddling4 ,this manipulation of scrap is known as the bushelling process and the product as 8bushelled iron0 or 8scrap bar40 ,by using scrap bar for the outer layers and old wrought iron bars cut to length for the interior1 box piles are made1 which1 heated and rolled1 make very good material1 though not as good as puddled iron4 ,certain grades on the market1 e4 g41 common bar iron1 contain more or less of this bushelled iron1 but the better grades1 refined wrought iron1 double refined wrought iron1 engine and stay-bolt iron1 are usually the pure puddled product4 ,as with the latter1 repeated shearing1 piling1 and rolling improve the quality4 ,bushelled iron is largely the result of an endeavor to reduce the cost of production of wrought iron4 ,the material has a legitimate place and considerable of it is used4 ,,chapter ,,vii ,,cementation ,,and ,,crucible ,,steels ,in the early days practically the only steels recognized--certainly the only ones desired--were of the high carbon or hardening variety4 ,these were required for the manufacture of swords and other implements of war1 for tools1 etc41 most of which had to have hard and sharp cutting edges4 ,when softer and less brittle metal was desired1 wrought iron was available1 but in all probability high carbon steel was the material most largely used4 ,having but the two iron alloys and these of very different properties1 it was not difficult to distinguish between them4 ,a piece of metal could be heated to redness and plunged into cold water4 ,if it became glass hard when cooled in this way it was thereby proved to be steel2 if still soft1 it was iron4 ,but the problem is not so simple to-day4 ,medium1 mild and yet softer steels1 and other alloys which have steel characteristics have appeared and are used in immense quantities4 ,their advent introduced considerable complication4 ,it will be well1 therefore1 before taking up our subject1 8,cementation and ,crucible ,steel10 and the several steels which are to follow1 to make sure that we all understand1 as well as we may1 what is 8steel0 as defined to-day1 what are the best known varieties1 and what are their characteristics8 ,for a rough classification it is safe for us to divide the steel world into four general divisions as follows3 #a4 ,the harder1 high carbon steels used for tools1 dies1 etc4 #b4 ,the mild and medium steels of which wire1 rod1 bar1 plate1 pipe and structural shapes for bridges1 ships and 8sky scrapers0 are made4 ,illustration3 ,,hardening ,a ,,piece ,,of ,,tool ,,steel4 ,,ready ,,to ,,quench #c4 ,alloy steels1 to which some metal such as nickel1 manganese or chromium gives definite properties and the name4 #d4 ,those other modern materials which are known as 8self-hardening0 and 8high-speed steels40 ,illustration3 ,,bowknot ,,made ,,from ,,piece ,,of ,,steel ,,pipe ,the two classes last named are not simple iron-carbon alloys and their properties are less directly derived from and do not so plainly depend upon carbon4 ,metallurgically1 then1 they are not steels in the exact former sense of the word2 but as they do require carbon--though perhaps in lesser amount1 are made by regular steel processes1 have most of the characteristics of steel and are used for the same general purposes1 they are undoubtedly entitled to the appellation 8steel40 ,however1 to distinguish1 they are usually termed 8alloy steels40 ,we are just now concerned only with the steels of classes one and two--the carbon steels4 ,as explained in a previous chapter1 these are alloys of iron with not more than #b per cent of carbon4 ,illustration3 ,,high ,,carbon ,,tool ,,steel 7#a4be ,,per ,,cent ,c7 ,,as ,,cast 7,magnification #gj diameters7 ,illustration3 ,,low ,,carbon ,,tool ,,steel 74#ej ,,per ,,cent ,c7 ,,annealed 7,magnification #gj diameters7 ,illustration3 ,,low ,,carbon ,,tool ,,steel 74#ej ,,per ,,cent ,c7 ,,as ,,cast 7,magnification #gj diameters7 ,illustration3 ,,medium ,,carbon ,,tool ,,steel 74#hf ,,per ,,cent ,c7 ,,as ,,cast 7,magnification #djj diameters7 ,carbon is the element the presence of which confers upon iron the ability to harden when cooled suddenly from a cherry-red heat1 as by quenching in water or oil4 ,if the steel contains less than four-tenths of one per cent of carbon it has little or no hardening power under this treatment2 but steel with six-tenths of one per cent or more of the element1 has the wonderful property of being slightly malleable when in the annealed state1 but extremely hard and brittle after this sudden cooling--leads a dual life1 so to speak4 ,illustration3 ,,low ,,carbon ,,tool ,,steel 74#ej ,,per ,,cent ,c7 ,,hardened 7,magnification #ajj diameters7 ,at any time1 hardened steel may be returned to its former condition of softness by the well known process of annealing1 wherein it is reheated to the same cherry-red heat and slowly cooled4 ,at the will of the blacksmith or metal worker alternate hardening and softening may be repeated a great many times without apparent deterioration4 ,various degrees of hardness also1 may be obtained according to 7#a71 the percentage of carbon in the steel1 and 7#b71 the completeness and suddenness of the cooling4 ,as considerable brittleness and internal strain in the metal necessarily follow hardening1 the hardness is usually 8tempered0 or 8let down0 by a careful reheating to a much lower temperature1 usually #dbe to #eej degrees ,fahrenheit4 ,from this temperature a second quenching 8fastens0 the temper at whatever of the original hardness the steel retains at the temperature chosen by the smith for the second quenching4 ,much of the brittleness is in this way relieved4 ,the smith calls it 8toughening0 the steel4 ,tools so treated are much less liable to break4 ,the steels that will harden 7we will call them 8carbon tool steels071 range ordinarily from the 4#fj per cent carbon variety1 used for hammers1 cold chisels1 etc41 to those containing #a4ej per cent of carbon which are selected for razors1 scalpels1 and other tools requiring high temper4 ,each one of these many grades is susceptible of a wide variety of temper in the hands of a capable man1 who must select his steel and give to it the most desirable temper for the work for which the tool is designed4 ,illustration3 ,,mild ,,steel ,,pipe 74#aj ,,per ,,cent ,c7 7,magnification #gj diameters7 ,blacksmiths and other tool makers become extremely proficient in judging steels and the proper temperature at which each should be hardened and 8drawn0 7tempered74 ,they judge temperatures solely by the color of the steel when heated4 ,every five or ten degree change imparts a slightly different shade as the steel grows hotter in the forge fire or cooler when about to quench4 ,observation of a good blacksmith at work and a few minutes' conversation with him about his 8art0 will give one greater knowledge and appreciation of the carbon tool steels than volumes of writings concerning them4 ,along with it will come more respect for the skill of these clever men whose handiwork is never exhibited in salons and about whom the world hears little1 though indebted to them for a great measure of its civilization and prosperity4 ,illustration3 ,,high ,,carbon ,,tool ,,steel ,,is ,,extremely ,,brittle ,,when ,,hardened ,,and ,,has ,,very ,,little ,,malleability ,,when ,,annealed ,what and how much would be possible without machines and proper tools8 ,illustration3 ,,quarter-,,inch ,,mild ,,steel ,,plate ,,with ,,double ,,fold4 ,,folded ,,cold ,,without ,,slightest ,,crack ,about sixty years ago steels of much lower carbon content appeared4 ,they have been made softer and softer until we have what we now know as the 8mild0 steels and even the almost or practically carbonless material which we called 8open-hearth iron0 or 8ingot iron0 in a former chapter4 ,these have not the hardening property but they possess softness1 ductility and freedom from brittleness which the higher carbon steels always lack4 ,for such real evidences of our ,twentieth ,century civilization as the great bridges1 ships1 buildings1 etc41 they are indispensable1 for they are easily cut1 bent and otherwise worked into shape1 and they combine pliability with sufficient strength for the service intended4 ,such steels are desirable1 for when overloaded they bend before they break1 thus giving warning of the danger4 ,these mild and medium steels are of immense importance industrially4 ,of the #ca1jjj1jjj tons of steel made in the ,united ,states during #aiab probably #ii per cent was of the soft and medium varieties4 ,it has been said that 8the exception proves the rule40 ,cementation steel is the exception to the rule which we gave in ,chapter ,,vi that steel is always melted during its manufacture4 ,if a thin piece of bar iron be packed in powdered charcoal and heated at low red heat for some time1 the metal1 after cooling1 will be found to have acquired the hardening property4 ,in other words by absorption of carbon it will have become steel with all of the characteristics of that material4 ,neither the iron nor the carbon by which it was surrounded have melted1 yet in some way carbon has penetrated into the iron and if the heating has been sufficiently long1 carbon will be found at the center of the bar4 ,but always there will be more carbon in the outer layers of the bar than in those farther inside1 i4 e41 it will be found in diminishing amounts as we approach the center4 ,illustration3 ,,shelby ,,seamless ,,steel ,,tubing ,,crushed ,,endwise ,just how and when the cementation process for making steel1 to be now described1 was discovered is not known4 ,it may have been the result of the non-uniform working of the larger blast furnaces which were developing in ,continental ,europe during the ,thirteenth century4 ,from the ,german 8natural steel0 which was probably the steely product too rich in carbon for the wrought iron which they intended to make and much too poor in carbon to be the fluid cast iron which with the growing height and heat of the blast furnace they later did make1 may have come the idea4 ,more likely1 a piece of thin wrought iron was accidentally left imbedded in glowing charcoal until it had absorbed some carbon4 ,illustration3 ,a ,,crucible ,,melting ,,room4 8,,melting ,,holes0 ,,are ,,beneath ,,the ,,square ,,covers ,,on ,,the ,,floor ,,at ,,the ,,left4 ,,note ,,the ,,new ,,crucibles ,,drying ,,on ,,the ,,shelves1 ,,and ,,the ,,ingot ,,molds ,,at ,,the ,,right ,the first mention of cementation steel appears to have been by an ,italian metallurgist1 ,vannuccio ,biringuccio1 who1 in #aedj1 described the making of steel by heating billets of soft iron for a long time in molten cast iron4 ,the modern method1 the heating of wrought iron in powdered charcoal1 was certainly known in the sixteenth century and this method of cementation has been practiced in ,france1 ,england1 ,belgium and ,germany since the seventeenth century4 ,illustration3 ,a ,,sheffield 7,,england7 ,,cementation ,,furnace ,reaumur1 the ,frenchman1 whose process of making cast iron soft by annealing bears his name and is still used in ,europe1 was the first to study and understand to any extent the cementation process4 ,publication1 about #agbb1 of his complete directions for cementing iron gave great impetus to the manufacture of steel by this process4 ,fate1 however1 was unkind and his own nation1 ,france1 by reason of her small production of suitable iron for the work1 was unable to profit greatly through his discoveries4 ,sweden1 ,england and ,germany were benefited to a much greater extent4 ,during the early years many were the secret and wonderful mixtures and compounds offered for this work1 but of them all carbon in some form was the only necessary element4 ,finely divided or powdered charcoal or bone dust has been mostly used4 ,illustration3 ,,huntsman ,,crucible ,,furnace--,,original ,,type ,illustration3 ,,one ,,type ,,of ,,oil-,,fired ,,crucible ,,furnace ,sheffield1 ,england1 steel makers1 have been very successful in the manufacture of cementation steel4 ,their usual method is to pack flat strips of best ,swedish ,walloon iron in charcoal in rectangular stone boxes about four feet wide1 three feet high and fourteen feet long4 ,alternate layers of small-sized charcoal and thin iron bars are piled in these boxes until they are filled1 the bars not being allowed to touch one another4 ,when full1 top slabs are luted on to the boxes to make them airtight4 ,fire is kindled in the firebox below and the heat gradually raised until furnace and boxes are cherry-red in color4 ,this heat is maintained for seven to eleven or more days1 depending upon the hardness desired1 i4e41 the amount of carbon they desire absorbed4 ,the furnace is closed and allowed to cool slowly1 which requires another seven or more days4 ,upon unpacking the furnace the bars are found to be brittle and of a steely fracture instead of the soft malleable material which was put in4 ,they have become high carbon steel4 ,expert workmen are able to judge very closely the hardness of the steel by looking at the fracture and they sort the bars in this way1 piling bars of similar hardness together4 ,illustration3 ,,huntsman ,,coke-,,fired ,,crucible ,,furnace--,,modern ,,type ,bars thus made show many blisters on the surface and the steel became known as 8blister steel0 on this account4 ,the reason for these blisters was not discovered until along about #ahfd1 when the well-known ,english metallurgist1 ,percy1 proved that the blisters were caused by the chemical action of carbon on the slag contained in the wrought iron4 ,the gases formed produced the blistering of the bar4 ,that this is the explanation is proved by the fact that bars of mild steel or iron without slag do not blister4 ,blister bars heated to a forging heat and drawn out under the hammer or rolled into bar steel are known as 8spring steel01 or 8plated bars40 ,as in wrought iron manufacture1 a cutting to length1 repiling1 heating1 welding and again drawing down by hammering or rolling produces much more homogeneous and reliable steel4 ,piled and reworked steel of this sort became known as 8shear0 steel because blades of shears for cropping woolen cloth were always made in this way4 ,many of us will recognize in the cementation process an extended 8case hardening40 ,case hardening is very largely resorted to by iron and steel workers1 who in a few hours can give a hardened and long-wearing thin outer layer of steel to a piece of iron or soft steel after it has been forged or machined into the desired shape4 ,illustration3 ,,siemen',s ,,gas-,,fired ,,crucible ,,furnace--,,regenerative ,,system ,one pair of ,checker-work ,chambers1 k4 h41 is being heated by the hot outgoing flame and waste gases while the other pair is heating incoming gas and air4 ,they are worked alternately4 ,this shear steel was largely made and was quite satisfactory1 until1 as described before1 ,huntsman1 a ,sheffield clock maker1 conceived the idea of melting together in a pot or crucible blister bars or bars of shear steel4 ,this he did to equalize the carbon content and give uniformity of product which had never been attainable through the cementation process alone4 ,from that date 7#agdj7 to this the crucible process has undergone only minor alterations and to-day it produces the highest grades of steel which we have4 ,practically all of the high grade tool steels are produced by this process4 ,nor has ,huntsman's form of furnace been greatly changed1 as the illustrations prove4 ,though gas and oil as well as coal are1 in many cases1 used as the fuel1 the general design of the furnace has remained the same4 ,for a century crucibles were made from clay molded to form1 slowly dried and very carefully burned4 ,usually each steel maker made his own crucibles4 ,they could be used but three times1 becoming so thin and tender after use for three batches of steel that they were not safe for a fourth4 ,graphite crucibles are now very largely used4 ,they withstand the severe heat much better and can be used five or six times4 ,the expense item for either clay or graphite crucibles is a large one4 ,illustration3 ,,the ,,stalwart ,,melters ,after filling with small pieces of blister or shear steel the crucibles are entirely surrounded by coal or coke in the furnace pit4 ,the fire is so regulated that the steel is not too quickly melted4 ,fresh coal or coke must be put in around the crucibles two or even three times4 ,when he thinks the steel should be molten1 the expert attendant known as the 8melter0 quickly removes the tight fitting cover of the crucible and with an iron rod determines whether any unmelted pieces remain4 ,after complete melting the steel must be 8killed10 else it will boil up in the mold upon pouring and leave a spongy or insufficiently solid 8ingot0 or block of steel4 ,this 8killing0 of steel is a rather peculiar phenomenon4 ,it is accomplished by allowing the steel to remain quiet in the furnace for another half hour or so4 ,undoubtedly the quieting is the result of the escape of the gases or impurities which are contained in the charge1 and absorption of the chemical element1 silicon1 from the walls of the crucible4 ,we have met this element1 silicon1 before in our metallurgical journey and we will likely meet it several times again4 ,to the metallurgist it is secondary in importance only to carbon4 ,illustration3 ,,pulling ,,the ,,crucible ,when the steel has been properly melted and killed it is ready to pour4 ,an assistant lifts the cover from the melting hole1 the 8puller-out0 seizes the crucible just below the bulge with circular tongs and pulls it from the coke which surrounds it4 ,the slag is skimmed off the top and the steel poured into iron molds forming small 8ingots10 usually from #b to #d inches square and two feet or more long4 ,every part of the process1 even the pouring1 must be done with extreme skill and care or the product suffers4 ,after liberation from their molds1 the ingots are heated and either rolled or hammered down to the sizes desired for tools1 etc4 ,as stated before1 crucible steel necessarily is an expensive material both on account of high labor and crucible costs4 ,for this reason1 many have resorted to the process used in the very small way mentioned for the manufacture of ,wootz steel--the melting of wrought iron bar or soft steel in a crucible with carbon4 ,in the ,wootz process chopped wood and green leaves were used4 ,nowadays charcoal is substituted or there is added the proper amount of cast iron to give the desired amount of carbon to the wrought iron or soft steel charged4 ,during the melting the iron takes up the charcoal and alloys with it4 ,illustration3 8,,teeming0 ,,or ,,pouring ,,into ,,ingots4 ,,the ,,ingots ,,later ,,are ,,forged ,,or ,,rolled ,,into ,,bars ,,from ,,which ,,the ,,tools ,,are ,,made ,proper amounts of silicon1 manganese1 and other beneficial materials are also charged1 which become either part of the alloy itself or have a cleaning or fluxing action upon it4 ,steels made in this way are practically1 though perhaps not quite1 as good as steels made by melting together the properly selected cementation bars4 ,the method has come to be very generally used on account of its directness and because it eliminates the long and expensive preliminary cementation process4 ,when ,bessemer and open-hearth steels made their appearance in the market an attempt was made to use them instead of wrought iron as the base for high grade crucible steels4 ,though seemingly pure enough1 apparently purer even than wrought iron1 these metals were not able to compete with wrought iron for this purpose4 ,for some reason1 not yet satisfactorily explained1 these new materials which are made in #ae1 #ce and #ej-ton batches1 when used as a base1 do not give as high quality tool steel as puddled wrought iron1 which is slowly and laboriously made in #ejj-pound lots4 ,considerable of these materials are utilized but it is for a somewhat lower grade of crucible steel4 ,for many years mild steels for castings have been quite largely made by the crucible process4 ,they are among the best but the crucible and labor costs are usually too great to allow crucible steel castings to compete in present markets4 ,,chapter ,,viii ,,bessemer ,,steel ,the 8,manufacture of ,malleable ,iron and ,steel without ,fuel0 was the startling title of a scientific paper read in #ahef before the ,british ,association for the ,advancement of ,science4 ,this was the announcement to the world of ,henry ,bessemer's invention of the process for making iron and steel which led to the greatest commercial development the world has seen4 ,to those of us who have had little or no experience along manufacturing lines the announcement seems strange enough1 but metallurgists1 engineers and manufacturers who know how serious is the matter of fuel bills realize at once how revolutionary the claim of ,bessemer must have seemed to men of those days4 ,as occurs with so many new things the idea was scoffed at2 ,bessemer's scheme was one purporting to give 8something for nothing0 and--well1 it could not be4 ,it was ridiculous6 ,and why should it not have seemed strange when we consider that up to that time fuel had been required in all metallurgical processes4 ,in the old ,catalan furnace and the types that preceded it1 in the ,finery ,fire1 the ,walloon and the several other refining furnaces fuel had to be provided without stint4 ,the lowest proportion that seventy years of experiment and practice had brought about in ,cort's puddling process was one ton of coal per ton of iron1 while the blast furnace required at the least four-fifths of a ton of coke for each ton of pig iron produced4 ,illustration3 ,,kelly',s ,,first ,,tilting ,,converter ,whether ,bessemer1 an ,englishman of ,french descent1 or ,william ,kelly1 an ,american of ,irish descent1 of ,eddyville1 ,ky41 first conceived the idea of the 8pneumatic0 process is a moot question4 ,considerable evidence substantiates the claim that the latter first hit upon the scheme and during the ten years between #ahdf and #ahef had considerable success with its development4 ,perhaps ,bessemer had heard of ,kelly's experiments4 ,there is no proof that he did4 ,whether he did or not1 the fact remains that he quite independently and very fully developed the process in ,england1 and with great business sagacity and energy made it the success that it is4 ,as fortune has withheld from ,kelly and from this country credit which was deserved1 it is desirable to tell briefly the part which he had in the development of this process that with a single furnace converts pig iron into steel at the rate of a thousand tons in #bd hours and first made mild steel available as a building material4 ,in #ahdf ,kelly1 with a brother1 bought the ,suwanee ,iron ,works1 near ,eddyville1 ,ky4 ,after about a year they encountered the same difficulty that charcoal iron manufacturers usually have encountered--the failure of the supply of fuel4 ,this difficulty ,kelly1 a better inventor than business man1 apparently had not foreseen4 ,his business was threatened unless some other way of refining his iron was found4 ,illustration3 ,,crucible ,,with ,,which ,,bessemer',s ,,first ,,experiments ,,were ,,conducted ,one day while watching the operation of his ,finery ,fire he noticed that the blast of air from the tuyre made the molten iron where it impinged very much whiter and apparently hotter than the rest4 ,like other iron makers1 he had always supposed that a blast of cold air chilled molten iron4 ,it appears that ,kelly was not long in surmising the truth4 ,in a few days he had rigged up a crude apparatus and made soft iron from which a horseshoe and a horseshoe nail were fashioned by a blacksmith4 ,illustration3 ,,fixed ,,converter ,,of #ahef ,,with ,,six ,,tuy,,res ,,about ,,the ,,sides ,being conservatives1 ,kelly's customers were not slow in informing him that they did not want iron made by anything other than the 8good old process0 and he was obliged to accede to their demands or lose their trade4 ,like ,galileo1 however1 he had not really surrendered4 ,in the woods near by he built and experimented with seven successive 8converters10 as the furnaces are called in which ,bessemer steel is made4 ,upon learning that ,bessemer of ,england had been granted a ,united ,states patent 7#ahef71 ,kelly came before the patent office and proved that he had several years before used the same process4 ,the priority of his invention was acknowledged1 and a patent was granted to him also 7#aheg74 ,illustration3 ,,bottom ,,blowing ,,tilting ,,converter ,financial troubles and finally bankruptcy handicapped him4 ,however1 the ,cambria ,steel ,co41 of ,johnstown1 ,pa41 became interested and let him experiment with his process at the company's plant4 ,here in #aheg he built his first 8tilting0 converter4 ,his first public demonstration resulted in failure and ridicule1 but a few days later he was successful4 ,steel makers bought interests in his patent1 which at its expiration in #ahgj was renewed by the ,united ,states ,patent ,office1 while renewal of ,bessemer's patent was refused4 ,illustration3 ,,in #aheh ,,bessemer ,,erected ,,his ,,first ,,converter ,,of ,,the ,,form ,,generally ,,used ,,to-,,day ,the ,kelly ,pneumatic ,process ,company1 which was organized to operate under ,kelly's patents1 built a converter at an iron works at ,wyandotte1 ,michigan4 ,here the first pneumatic process steel ever made in this country in other than an experimental way was 8blown0 in #ahfd4 ,meanwhile ,alexander ,l4 ,holley1 an ,american engineer1 had obtained for another ,american company the right to manufacture steel here under ,bessemer's patents4 ,he built a plant at ,troy1 ,new ,york1 which began making steel in #ahfe4 ,illustration3 ,,even ,,the ,,detachable ,,bottom--,,to ,,facilitate ,,repairs--,,was ,,thought ,,of ,,and ,,patented ,,by ,,bessemer--#ahfc ,it was soon decided to merge the interests of the two companies and in #ahff this was done1 the process thereafter being known as the ,bessemer ,process4 ,during the early years of the process here ,holley became very well known4 ,as consulting engineer he designed practically all of the ,bessemer plants which were built during the first ten or fifteen years4 ,to the majority of the people of the ,united ,states to-day ,kelly and his parallel part in the great invention are practically unknown1 and thus not only he but the ,united ,states is without credit which should be ours4 ,fortunately ,kelly did not entirely fail to profit financially as so many times is the case with inventors4 ,he received a total of about #ejj1jjj4 ,bessemer's return from his process is said to have approximated #aj1jjj1jjj and he was knighted by the ,british sovereign4 ,more intimate details regarding ,kelly and his work may be found in ,munsey's ,magazine for ,april1 #aijf1 where ,h4 ,casson gives information which he received direct from several of the men who knew and worked with ,kelly4 ,while apparently not the originator of the process1 ,bessemer is without any doubt entitled to most of the credit he received4 ,there is no proof that he had heard of ,kelly's experiments when he began his own or that he was aided by ,kelly's discoveries4 ,he worked out the details of the process independently1 as had ,kelly1 and it was ,bessemer who put it on a commercial basis4 ,as has occurred with other new processes ,bessemer's first licensees were not particularly successful4 ,when those who had bought the right to use his process had failed in their efforts to use it1 and become discouraged as most of them did1 he quietly bought back their rights and went ahead with his development of the process4 ,perhaps no man ever exhibited more perseverance in continuing experiments and development under very discouraging conditions than did ,henry ,bessemer4 ,he had faith4 ,illustration3 ,,sectional ,,view ,,of ,a ,,modern ,,converter ,,showing ,,air ,,duct ,,and ,,tuy,,res ,he had a genius for invention and was thorough in his experimental work4 ,practically no type of converter has since been brought out that he did not think of and try1 and the process has been modified in but one or two important particulars in the years that have passed4 ,the essential part of the ,bessemer process is the blowing of air through molten cast iron to remove the metalloids by which cast iron differs from steel and wrought iron1 as has been explained before4 ,this being the essential point1 and at first thought the lack of fuel seeming so peculiar1 we must describe what happens during the ,bessemer 8blow40 ,illustration3 ,,pouring ,,charge ,,of ,,molten ,,pig ,,iron ,,into ,,converter ,technically speaking1 the metalloids are 8oxidized40 ,oxidation is the chemical uniting of oxygen1 generally from the air1 which has #ba per cent of this element1 with another element or material such as iron1 silicon1 carbon1 wood1 coal1 etc4 ,if the oxidation is slow as in the 8rusting0 of iron1 the resulting heat dissipates as fast as it is generated and the change is hardly noticeable4 ,if1 however1 the reaction occurs rapidly and with vigor enough1 we say that the material 8burns40 ,the latter sort of oxidation is what we call 8combustion40 ,the affinity between the metalloids and oxygen has been noted by us before1 but in those cases most of the oxygen came from a different source4 ,in the wrought iron process most of it was furnished by the iron ore or scale which was stirred into the metal1 or by the slag which covered the 8bath40 ,in the ,bessemer1 or as it was first known in ,america1 8,kelly's air blowing process10 the oxygen of the air blown through the molten metal directly oxidizes or burns out the carbon1 silicon1 and manganese4 ,the extremely rapid oxidation of these furnishes the heat4 ,the iron1 then1 furnishes its own fuel and no outside combustible is needed4 ,how can this be8 ,in every ton of molten cast iron there are approximately #gj pounds of carbon1 #be pounds of silicon1 and #ae pounds of manganese or a total of about #bjjj pounds of these metalloids in the fifteen-ton charge of molten metal which goes into the ordinary steel plant converter4 ,we know that if burned in a furnace this ton of high grade fuel would generate much heat4 ,burned inside of the mass of molten metal it generates exactly that same amount of heat and the heat is applied with such rapidity1 directness and efficiency that the molten iron which had a temperature of #bcjj ,f41 say1 when charged1 in nine or ten minutes has become steel with a temperature of about #cjjj ,f4 simply through this rapid oxidation of its #d to #f per cent of metalloids4 ,how the blast under #ae to #cj pounds per square inch is applied through little nozzles in the bottom of the modern 8converter0 and the several types of vessels with which ,bessemer experimented in the course of his investigations are shown in the illustrations4 ,nor is it necessary that the air be blown through the metal4 ,air blown upon its surface accomplishes practically the same purpose1 and in many of the steel foundries of to-day smaller converters of this 8surface-blown0 type are used for producing steel for castings4 ,the large steel plants1 however1 use the larger 8bottom-blown0 converter4 ,two or three of these vessels1 working with proper metal from the 8mixer10 produce an immense tonnage of steel each #bd hours4 ,the 8mixer0 is quite necessary4 ,it is a large vessel or furnace holding and keeping hot from #ge to #cjj or more tons of metal from the blast furnace4 ,it mixes and equalizes irons of various compositions1 so that the converters have the advantage of uniform and hot metal with which to work4 ,in addition it is made to perform a 8refining0 service4 ,by mixing into the metal a quantity of manganese1 considerable of the sulphur present 7a deleterious substance7 is removed4 ,the fifteen or twenty minute blowing of #ae tons of metal in the big egg-shaped converters of a steel plant presents a spectacle which1 when once observed1 will never be forgotten4 ,one sees a little 8dinky0 engine come shooting into the converter building with its ladle of molten iron from the 8mixer40 ,with ,america's time saving routine not a single minute is lost while emptying the metal into the converter1 now in a horizontal position4 ,almost before the ladle is out of the way1 the converter swings to the upright position with the blast already on1 for otherwise the metal would flow into the tuyre holes at the bottom4 ,illustration3 ,,comparison ,,of ,,ingots ,a4 ,from ,four ,pot ,crucible ,furnace3 ,each ,heat #djj ,pounds in #d ,hours or #ajj ,pounds an ,hour1 ,each ,heat ,pours #d ,ingots #c #c #cf4 ,b4 ,from ,fifteen ,ton ,bessemer ,converter3 #cj1jjj ,pounds in #bj ,minutes or #ij1jjj ,pounds an ,hour1 ,each ,heat ,pours #f ,ingots #ai #bj #fb4 ,c4 ,from ,fifty ,ton ,open-,hearth ,furnace1 #ajj1jjj ,pounds in #h ,hours or #ab1ejj ,pounds an ,hour1 ,each ,heat ,pours #f ,ingots #bd #cb #gb4 ,reddish-brown smoke and a shower of sparks come from the converter4 ,these gradually develop into a flame4 ,the blast shows considerable partiality in selecting for its first attention the metalloids silicon and manganese1 in preference to the iron itself or any other of the metalloids present4 ,after from three to five minutes half of the silicon and manganese have been burned out4 ,if the temperature of the metal and other conditions have become right the carbon then begins to burn4 ,this gives a change in the nature of the flame which becomes large and of a dazzling whiteness4 ,the metal is hot--very hot--so much so that pieces of cold steel often must be dropped in to cool it somewhat4 ,this is known as 8scrapping0 the charge4 ,an experienced blower can judge through every period of the operation of the condition of his metal and just how things are progressing4 ,after some minutes the flame begins to waver and later 8drops02 i4e41 there is scarcely a flame at all4 ,this signal1 which is very definite to an experienced man1 cannot be lightly disregarded4 ,oxygen has affinity for iron as well as for the metalloids and it is only because of its greater love for silicon1 manganese and carbon that it has thus far largely neglected the iron4 ,with the metalloids mentioned out of the way1 as they are when the drop occurs1 the iron will begin to burn4 ,were the 8blowing0 continued we would shortly have no iron left1 but in its place a mass of iron oxide and slag4 ,thus we see that during the first minutes of the blow1 more than one-half of the silicon and manganese are burned4 ,the remainder of these and all of the carbon are removed in the subsequent five or six minutes4 ,at the end of this short blowing period we have practically pure iron4 ,illustration3 ,,two ,,converters ,,in ,,operation ,,and ,a ,,third ,,pouring ,the metal is not yet in condition to pour well1 however1 largely because of the dissolved air and gases which it holds4 ,something akin to the 8killing0 of the steel which we observed in the crucible process must be accomplished or ingots from it will be spongy4 ,and1 having practically no carbon1 it is not yet 8steel40 ,bessemer1 knowing that the finished steel should contain carbon1 tried to stop the blow long enough before the drop of the flame to leave exactly the desired amount of this element4 ,he found this difficult to do and therefore uncertain4 ,it was found to be far better to blow until the drop of the flame and then put back sufficient carbon to give the proper composition4 ,an ,english metallurgist named ,mushet discovered that addition of manganese ridded the metal of injurious gases and oxides and what is known as 8red-shortness40 ,after a period of difficulty without it ,bessemer acknowledged the necessity of manganese and adopted its use4 ,it had before this been used in crucible steel4 ,upon turning down the converter at the drop of the flame1 the blast is turned off and a smaller ladle is run in on a track above4 ,this brings a molten mixture of irons1 usually known as 8spiegel0 or 8spiegeleisen0 which contains just enough carbon1 manganese and silicon to give to the whole of the molten metal in the converter the metalloids needed to make of it steel of the composition desired4 ,this addition also accomplishes the 8deoxidation0 of the metal4 ,by deoxidation we mean that the iron is relieved of the oxygen and gases which have remained as a result of the blast4 ,this is necessary in order to give proper fluidity for pouring and the best physical properties to the finished steel4 ,after 8recarburization10 as this addition of manganese-silicon-carbon metal is called1 the steel and slag are quickly poured out into a ladle waiting below from which the steel is 8teemed0 7i4e41 poured71 through a 8nozzle0 or hole in the bottom into ingot molds arranged on trucks on the railroad track which runs through the building4 ,illustration3 ,,teeming ,,the ,,finished ,,steel ,,into ,,the ,,ingot ,,molds ,when the molds have been filled and a strong crust develops on the steel the cars are pulled to the 8stripper0 where the molds are removed1 leaving the white-hot ingots standing on the cars4 ,the ingots mentioned in the chapter on ,cementation and ,crucible ,steel were usually small enough that one pot of #ajj pounds of metal filled the mold4 ,a four pot furnace therefore produced #djj pounds4 ,now for the first time1 we are talking in tonnage figures4 ,instead of a batch of steel making four #c #c #cf ingots of #ajj pounds each1 the ordinary 8heat0 of ,bessemer steel from the #ae-ton converter gives six or seven ingots about #ah #bj #fj in size4 ,each of these weighs about two tons4 ,the total is #cj1jjj pounds4 ,from the stripper the ingots go to the gas-fired soaking pits where the molten interiors of the ingots gradually solidify by cooling while the outer crusts are reheated4 ,after equalizing the temperatures of exteriors and interiors in this way1 the ingots are white-hot again and ready for rolling4 ,illustration3 ,,molds ,,being ,,stripped ,,from ,,ingots ,the purpose for which the steel is intended1 of course1 determines the shapes and sizes into which the ingots are rolled4 ,for rails they are rolled down directly1 each ingot making about six rails1 of thirty-three-foot length4 ,for most other purposes the ingots are rolled in the slabbing mill into billets or slabs which are of intermediate shapes and sizes which are reheated and further rolled down into axles1 bars1 shapes1 wire or other products4 ,meanwhile the converter which we saw emptied has not been idle4 ,the ,american steel engineer has genius for mechanical efficiency and all parts of a great steel plant are so co-ordinated that enormous quantities of material can be handled with not a moment lost between trips4 ,almost before the ladle of steel had swung away from the converter's mouth1 any remaining slag was dumped from the converter by further tipping1 the vessel returned to receiving position and the ladle car1 back again from the mixer1 poured in the next charge4 ,thus blow after blow is made without loss of time4 ,repairs are allowed to take no longer than is absolutely necessary4 ,when the lining around the tuyres gets too badly cut by the action of the air and metal the bottom is removed1 another one is quickly substituted and the steel making goes on4 ,blowers1 ladlemen1 cranemen1 pourers1 patchers1 vesselmen1 sample boys and the other workmen are relieved by their 8partners0 at the end of each shift1 each man of necessity working until relieved--twelve1 twenty-four1 or even thirty-six hours1 for there must be no delay4 ,so day and night1 through the entire week from ,monday morning at six1 when they begin1 until the next ,sunday morning at six1 when the plant shuts down for a brief spell1 the converters go on turning out three heats per hour or four to five hundred per week each4 ,it has been mentioned that most of ,bessemer's first licensees failed with the new process4 ,the reasons for this were various1 but one in particular was the attempt of many to use metal of high phosphorus content4 ,bessemer soon discovered that no phosphorus was removed during the 8blow0 and that1 as phosphorus in quantity over one-tenth of one per cent was detrimental to steel1 it was necessary to use raw material which had little of this element4 ,this could be done1 but it barred many pig irons otherwise good4 ,fortunately ,swedish and many ,english irons had low phosphorus4 ,germany's vast beds of high phosphorus ores1 however1 were useless for the purpose4 ,for twenty years this situation existed1 during which time many metallurgists endeavored to make the process applicable to irons which contained high phosphorus4 ,after long study and many experiments the problem was solved by ,sidney ,thomas1 an ,english metallurgist4 ,with a cousin1 ,percy ,gilchrist1 he made hundreds of blows with a toy converter holding only eight pounds of iron4 ,bessemer's linings had been of sand1 clay and other earths which are known chemically as 8acid0 materials4 ,by using 8basic0 materials such as limestone1 dolomite1 etc41 for the converter lining and additions of limestone or burnt lime to the charge before and during the blow to make and keep the slag 8basic10 ,thomas was able to make the phosphorus burn after the carbon had been removed4 ,therefore1 a three or four minute 8after blow0 following the 8drop0 of the carbon flame took out the phosphorus1--again1 with generation of heat4 ,so there are two varieties of the process--the acid ,bessemer and the basic ,bessemer1 but the former1 only1 is used in this country as we have few high phosphorus ores4 ,the analogous open-hearth processes1 which are next to be described1 are both used in this country with the basic open-hearth greatly in the lead4 ,however1 the basic ,bessemer process of ,thomas and ,gilchrist is credited with making ,germany's great industrial development possible4 ,year ,,table ,,no4 #a ,,table ,,no4 #b ,materials ,used for ,rails#f ,total ,steel ,made by ,processes#f ,wrought ,bessemer ,open-,hearth ,bessemer ,open-,hearth ,crucible ,iron ,steel ,steel ,steel ,steel ,steel #ahdi #ba1gaj #ahej #ci1cfj #ahee #abd1jjj #ahfj #ahc1jjj ,no ,data #ahfe #cah1jjj #ahfg #daj1jjj #b1bhj #b1fgi #ahfh #dde1igj #f1dej #g1ehi #ahfi #eba1cgj #h1fbj #aj1gad #hic #ahgj #ebc1jjj #cj1cfj #cg1ejj #a1cci #ahgeddh1jjj #bfj1jjj #cce1jjj #h1jhj #ce1ahj #ahhj #dda1jjj #heb1jjj #ab1afj #a1jgd1jjj #aaj1hej #fd1ffj #ahhe #ac1jjj #iei1jjj #d1bhj #a1eae1jjj #acc1jjj #eg1fjj #ahij #ad1jjj #a1hfh1jjj #c1eij #c1fhi1jjj #eac1jjj #ga1bjj #ahie #e1haj #a1cjj1jjj #gjj #d1iji1jjj #a1acg1jjj #fh1gjj #aijj #fie #b1chd1jjj #a1ccj #f1fhe1jjj #c1cih1jjj #ajj1ejj #aije #cah #c1aib1jjj #ahc1jjj #aj1ida1jjj #h1iga1jjj #ajb1bjj #aijf #ae #c1cia1jjj #ahf1jjj #ab1bgf1jjj #aj1ihj1jjj #abg1ejj #aijg #ibe #c1chj1jjj #bec1jjjaa1ffh1jjj #aa1eej1jjj #aca1jjj #aijh #ga #a1cdi1jjj #egb1jjj #f1aag1jjjg1hcg1jjj #fc1fjj #aiji #a1gfg1jjj #a1beg1jjj #i1cca1jjjad1did1jjj #ajg1djj #aiaj #bcja1hhd1jjj #a1gea1jjj #i1dac1jjjaf1eje1jjj #abb1cjj #aiab #a1ajj1jjjb1aje1jjj #aj1cbh1jjjbj1ghj1jjj #aba1ejj #aiac #hah1jjj #b1ebh1jjj #i1edf1jjjba1fjj1jjj #aba1bjj #aiad #cbd1jjj #a1ebf1jjj #f1bba1jjjag1age1jjj #hi1ijj #aiae #cbg1jjj #a1gge1jjj #h1bhg1jjjbc1fgi1jjj #aac1hjj #aiaf #ddj1jjj #b1bgj1jjj #aa1jei1jjjca1dae1jjj #abi1gjj ,footnote #f3 ,in ,united ,states--long tons of #b1bdj pounds4 ,the well-known 8,thomas ,slag0 which is in demand as a fertilizer on account of its phosphorus content is the by-product of the basic-lined converter4 ,an idea of what the invention of the ,bessemer process meant to railroad development alone may be gained by studying for a moment ,table ,no4 #a4 ,wrought iron was our first material for rails1 but1 being very soft1 it did not give long service4 ,but a short time was required for ,bessemer steel to displace it for rails when steel became available4 ,the greater uniformity1 strength and hardness of the alloy gave such excellent wearing properties that few rails of iron were laid after the year #ahhj4 ,during recent years rails have been made of greater and greater strength and hardness to keep pace with the fast increasing weight1 speed and frequency of railroad trains1 steel being susceptible to much modification of properties4 ,now it appears that ,bessemer steel is giving way to other products which show even superior properties4 ,what happened in the railroad world to a great extent has happened elsewhere1 as the figures of ,table ,no4 #b show4 ,they are a barometer which indicates what has been our industrial development and our advance in civilization4 ,,chapter ,,ix ,,the ,,open-,,hearth ,,process ,bessemer's was a wonderful process1 but the time seemed to be ripe for great development along metallurgical lines1 and the method of converting pig iron into steel which he devised soon had a competitor which was destined eventually to take the lead in steel production4 ,many years passed before the tonnage turned out annually by ,bessemer's process was equaled by that of the new1 but as shown in the last chapter the ,siemens-,martin or open-hearth process in #aijg produced the greater tonnage4 ,it has since retained its lead and probably will continue to do so4 ,as far back as #ahde ,john ,marshall ,heath took out a patent for a process for making steel patterned after the old puddling process4 ,in a way he may therefore be said to have devised or forecast the open-hearth process1 but because of the great obstacles that had to be surmounted in getting a furnace that would fulfill the requirements he was unable to carry out his scheme4 ,you will remember that in the puddling furnace the purified metal became pasty because of its high melting point4 ,because of the great heat required it was not until the invention of the regenerative system by ,c4 ,w4 ,siemens in #ahfj that the open-hearth process was possible4 ,siemen's furnace was the first one that could keep the iron molten4 ,it was in ,birmingham1 ,england1 that the first successful open-hearth furnace was used4 ,illustration3 ,,early ,,type ,,of ,,gas ,,producer1 ,,regenerators1 ,,and ,,open-,,hearth ,,furnace4 ,,course ,,taken ,,by ,,air1 ,,gas1 ,,and ,,products ,,of ,,combustion ,,are ,,plainly ,,shown1 ,,as ,,are ,,the ,,valves ,,that ,,reverse ,,direction ,,of ,,flow ,while not as speedy nor as prolific a producer as the ,bessemer process and far less spectacular1 the open-hearth has several advantages4 ,the acid ,bessemer was always handicapped because pig iron with less than #j4a per cent of phosphorus was necessary4 ,the majority of ores carry more than this amount4 ,the basic ,bessemer requires pig iron containing not less than #b per cent of phosphorus4 ,the vast quantities of material which contain percentages of phosphorus between these limits are useless as far as the ,bessemer process is concerned4 ,to be successfully used the pig iron must be further limited as to composition4 ,it must have sufficient silicon1 manganese1 and carbon to give the heat required for ,bessemerizing1 as the burning of these metalloids has to be depended upon for the conversion to steel and to give proper fluidity to the finished alloy4 ,then1 too1 the large amount of air forced through to a certain extent 8over-oxidizes0 the bath and some of the gases are mechanically retained by the steel no matter how complete the deoxidation4 ,there also is loss of metal due to unavoidable 8spitting10 for the rapid streams of air mechanically carry some metal and slag with the flame out of the vessel4 ,on the other hand1 for the open-hearth process can be used pig iron of widely varied character and composition and1 further1 large percentages of low-priced steel scrap can be utilized in the charges2 as no air is blown through the metal and little comes in contact with it1 the conversion takes place quietly and smoothly and with much less loss by oxidation1 the yield of steel usually being from #ij to #ig per cent of the metal charged as against #hc to #hg per cent which is the yield by the ,bessemer process2 besides giving less over-oxidation and gases in the metal1 the slowness of the conversion is an advantage1 as control is very easy1 and1 when desired1 samples for test may be taken4 ,from his tests the melter can be quite certain when he taps out the steel that it is of the composition desired4 ,illustration3 ,,section ,,through ,,typical ,,stationary ,,open-,,hearth ,,furnace1 ,,showing ,,construction ,,of ,,furnace1 ,,lining1 ,,bath ,,and ,,air ,,and ,,gas ,,ports ,the melting in an open-hearth furnace is done largely by indirect or radiated heat1 and it is not intended that the flame shall impinge too directly upon the surface of the bath4 ,illustration3 ,,boxes ,,of ,,steel ,,scrap ,,and ,,electric ,,charging ,,machine ,,in ,,front ,,of ,,charging ,,doors ,,at ,,rear ,,of ,,furnaces ,except during the melting down of the pig iron and other materials charged in the furnace1 the flame and air take little part in the actual elimination of the metalloids4 ,their main function is to furnish the heat necessary4 ,being used so indirectly--mostly by radiation from the roof and walls--very great heat must be used and much would be wasted if special precautions were not taken to save it4 ,the bath must be kept hot enough to remain molten after purification of the metal1 which we were unable to accomplish in the wrought iron puddling furnace4 ,under each end of the rectangular furnace are two chambers built up with checker-work of fire brick4 ,these sets are in duplicate and each has one chamber for air and one for gas4 ,illustration3 ,,charging ,,machine ,,with ,,box ,,of ,,scrap ,,half ,,way ,,into ,,furnace ,thus an open-hearth furnace will be seen to occupy a sort of hollow square1 the furnace proper forming one side1 the regenerative chambers two sides1 with the chimney and flues the remaining side4 8,reversing0 valves force the incoming gas and air to travel each through its respective hot regenerating chamber up through the ports and into the furnace where they unite and burn with a very hot flame4 ,the hot gases leave through similar ports in the other end of the furnace and on their way to the chimney heat the checker-work in the regenerative chamber4 ,every fifteen or twenty minutes the valves are reversed and the direction of flow is changed4 ,in this way the incoming gas and air are preheated and in the furnace burn with a very much hotter flame than would cold gas with cold air4 ,no blast is required1 the draft caused by the chimney being sufficient4 ,for protection of the roof from the great heat developed and the metal of the bath from too great oxidation1 the air ports usually are located above the gas ports4 ,the streams of air1 while protecting the roof from the flame1 at the same time are prevented from directly impinging upon and too strongly oxidizing the metal of the bath4 ,the diagrammatic sketches given show roughly a furnace1 regenerative chambers1 ports1 etc4 ,illustration3 ,,charging 8,,hot0 ,,metal ,the original intention was to melt pig iron and reduce it2 i4 e41 burn out the silicon1 manganese1 and carbon by action of the flame and addition of iron ore4 ,this was the process worked out by ,siemens in ,england4 ,in ,france1 ,p4 and ,e4 ,martin altered the method by diluting molten pig iron in the ,siemens furnace by melting and dissolving in it steel scrap4 ,it was soon found that a combination of the two methods was better than either one alone and the open-hearth process acquired its name--the ,siemens-,martin--in this way4 ,in the ,united ,states about #bj1jjj1jjj tons of steel are made annually by the basic open-hearth process while only #a1ajj1jjj tons are produced by the acid open-hearth process4 ,the two processes are practically the same except that by the basic process the phosphorus as well as the silicon1 manganese1 and carbon are reduced or eliminated4 ,in order to take out the phosphorus1 additions of lime 7i4 e41 calcium oxide or calcium carbonate7 are made just as occurred with the basic ,bessemer process4 ,should we use lime in a furnace having an acid lining1 much of the lime1 which is a 8base10 would react with the 8acid0 7silica7 bricks of the lining1 and1 becoming neutralized1 would not do its work4 ,so1 as in the basic ,bessemer process1 we here have to use either 8basic0 or 8neutral0 lining4 ,the material generally used is burnt magnesium carbonate which is known as 8magnesite40 ,dolomite1 which is a combination of the carbonates of calcium and magnesium1 is sometimes used4 ,chrome bricks1 the usual neutral material1 are rather too expensive for extensive use4 ,the best magnesite comes from ,austria and is usually not very cheap4 ,as acid materials 7those of silica or clay7 are cheaper and mechanically stronger1 a compromise is ofttimes effected by using basic materials for the furnace bottom and acid bricks for the sidewalls and roof4 ,a few rows of chrome bricks may be put in to form a neutral dividing line just at and above the edge of the bath where the action of the slag is the most severe4 ,it also serves to keep the basic and acid materials apart and from reacting with each other4 ,at the commencement of charging1 limestone or sometimes burnt lime is shoveled in upon the bottom or 8hearth0 of the white-hot furnace4 ,when cold metal is charged1 the pigs of iron are conveyed into the furnace by the melter and his helpers by means of long handled flat iron tools called 8peels40 ,this is followed by charging some or all of the scrap or iron which is to be made a part of the charge4 ,even in the smaller #ae or #be-ton furnaces hand charging takes a great deal of time1 sometimes as much as six or eight hours1 and the labor cost as well as the heat loss is therefore excessive4 ,modern machine charging which requires not more than an hour is therefore highly desirable4 ,illustration3 ,,row ,,of ,,open-,,hearth ,,furnaces ,,showing ,,pit ,,or ,,tapping ,,side ,during the melting down of the pig iron with the scrap that has been charged1 the air and flame burn out about half of the silicon and manganese of the metal4 ,to remove the remainder of these and the carbon of the charge1 additions are made from time to time of sufficient ore to keep the bath 8boiling40 ,this phenomenon results from the giving off of carbon monoxide gas formed from the oxygen of the iron ore and the carbon of the metal1 just as happened when the puddler in the manufacture of wrought iron used iron ore in his furnace4 ,the covering of slag which forms and protects the bath from the flame undoubtedly transfers oxygen from the furnace gases to the bath and this helps to burn out the carbon4 ,the lime charged unites with the phosphorus of the iron and takes it into the slag which covers the bath4 ,if necessary1 further additions of lime may be made from time to time during the melting and the 8working down0 7elimination of the metalloids7 of the charge4 ,as long as the slag is kept basic it retains the phosphorus1 but should it turn acid the iron of the bath would take the phosphorus back again4 ,these reactions are all chemical1 just as much so as are the burning of wood and coal and the thousands of reactions which are brought about in chemical laboratories4 ,additions of ore are made from time to time and the bath rabbled4 ,samples are taken now and then with a long handled iron spoon or ladle and these are poured into molds to form small bars of steel1 which1 after quenching1 are broken4 ,illustration3 ,,open-,,hearth ,,furnace 8,,tapping0 ,the melter has become very proficient in judging the composition of the metal of the bath from the fracture of these broken test pieces4 ,by means of the samples taken he watches the elimination of the metalloids4 ,when he thinks the reactions have progressed far enough he takes a last sample which is rushed to the chemist who makes a hurried 8control0 analysis for carbon and phosphorus1 the metal being held in the furnace meanwhile4 ,if the results of this analysis show the bath to have the desired composition the steel is poured4 ,if the reactions have not been complete1 the chemist's report shows that the carbon and perhaps the phosphorus are still too high1 in which case the charge must be still further worked down4 ,some melters are able to make fairly uniform and satisfactory steel without a chemist1 but for best results a chemical laboratory is desirable4 ,when ready to tap1 the big ladle is suspended from a crane under the spout of the furnace4 ,with a tapping bar the plug of clay is removed from the tap hole and the molten steel gushes out into the ladle4 ,the slag which has covered the bath is the last to drain out4 ,many times this will overflow the ladle1 making a beautiful cascade as it pours over the sides all around to the floor beneath4 ,especially at night is this a glorious sight4 ,illustration3 ,,teeming ,,the ,,steel ,,into ,,ingot ,,molds ,recarburization is not done to the same extent as it is in the ,bessemer process4 ,as the open-hearth elimination of carbon is slower and under so much better control1 the furnace usually is tapped when the carbon has been reduced to the percentage desired in the finished steel4 ,when it is necessary to add carbon it is done sometimes by adding pig iron to the bath and sometimes by throwing a weighed amount of coal or coke in the ladle as the steel is going in4 ,molten iron and steel have strong appetites for carbon and dissolve it very readily4 ,ferro-manganese is used to prevent red-shortness and to deoxidize the metal4 ,this also is usually put into the ladle as too much loss would occur were it added in the furnace4 ,while the furnace is again being charged through the charging doors at the rear1 the steel is teemed through the nozzle of the big ladle into the waiting ingot molds4 ,these go to the stripper1 to the soaking pits1 and then to the rolls of the blooming mills just as did the ,bessemer ingots4 ,illustration3 ,,at ,,the 8,,stripper0 ,in the acid-lined furnace no attempt is made to reduce the phosphorus4 ,it would be futile4 ,therefore the materials charged must be very low in phosphorus and sulphur4 ,no lime additions are made1 the flame simply melts down the pig iron and scrap1 the iron oxide later is added from time to time to keep up the boil until the test bars show that the carbon as well as the silicon and manganese have been eliminated as fully as is desired4 ,the metal is then tapped as described above4 ,three or more hours are usually required to melt down cold charges4 ,the elimination of the remainder of the silicon1 manganese1 and the carbon requires about four or five hours more4 ,so for each heat the open-hearth furnace requires from eight to twelve hours1 depending largely upon the speed of charging and melting4 ,of late years the difficulties attending the use of molten metal from the blast furnace in place of cold pig iron have been largely surmounted4 ,the use of uniform metal from the 8mixer10 which was described in the article on the ,bessemer process1 has aided the open-hearth process also4 ,of course1 when molten metal is added none of its silicon and manganese is reduced by the flame as occurred with the cold metals during the melting down1 so the molten metal charged is usually low in these elements to compensate4 ,by use of 8hot0 7molten7 metal the time necessary to produce a 8heat0 of steel is considerably shortened4 ,the first and perhaps the majority of furnaces yet building are 8stationary40 ,some have found it advantageous to construct furnaces that can be tipped to pour the metal into the ladle4 ,such are known as 8tilting0 furnaces4 ,one furnace designer has even gone so far in a smaller type used for steel castings as to make the furnace removable1 thus doing away with a ladle entirely4 ,the big crane simply lifts the whole furnace out from between the housings which contain the ports4 ,it is taken bodily to the molds which are poured directly4 ,open-hearth furnaces have been built of larger and larger capacity4 ,a great many fifty-ton furnaces have been built and furnaces which produce eighty or more tons at a heat are now not uncommon4 ,furnaces of the ,talbot type are built for as much as #bjj and even #cjj tons of metal1 but from these only part of the finished steel is tapped at a time1 the remainder being left to help work down the additions of new material which is added to replace the steel tapped out4 ,the rolling mill industry is so intimately connected with and dependent upon the steel-making methods and equipment that each is designed with reference to the other4 ,bessemer steel has been largely used for the manufacture of rails1 rod1 wire1 pipe1 merchant bar1 etc41 while open-hearth steel has gone into plate1 boiler tubes1 structural shapes1 billets for axles1 etc4 ,recently it is being used for rails and very many of the products which were formerly made from ,bessemer steel4 ,illustration3 ,,lower ,,half ,,of ,a 8,,battery0 ,,of ,,modern ,,gas ,,producers ,it should not be inferred from this that ,bessemer steel is no longer in demand or that it is not good steel4 ,as you will notice from the table given in the last chapter1 the production of ,bessemer steel has not declined appreciably1 if at all4 ,the fact is that open-hearth steel production has been increasing at a great rate1 while the production of ,bessemer has remained stationary4 ,with the growing scarcity of ores suitable for pig iron for ,bessemerizing1 the open-hearth process is becoming able to compete with the ,bessemer process in the matter of cost4 ,for some purposes the steel is considered to be a little more desirable1 but1 as is the case with many good things1 the pendulum swings too far and there is no doubt that open-hearth steel is often demanded and used for purposes for which ,bessemer steel would be just as good and perhaps better4 ,for many years it has been said that the ,bessemer process is 8doomed40 ,this1 of course1 was because of the scarcity of low phosphorus ores4 ,just how 8doomed0 it is1 it is perhaps impossible to say4 ,certainly it is still a very live process and the combining of processes1 such as 8duplexing10 will probably prolong its life4 ,by the 8duplex0 process1 molten blast furnace iron from the mixer is 8desiliconized0 in the ,bessemer converter4 ,before too much of the carbon has been burned1 the metal is transferred to a basic open-hearth furnace where the remainder of the carbon and most of the phosphorus is removed4 ,by this method the advantages of the open-hearth and much of the speed of the ,bessemer process are combined4 ,the output of the open-hearth furnace is thus greatly increased4 ,to-day all kinds of combinations of ,bessemer1 open-hearth1 and electric furnace are being projected and it is difficult and likely impossible for any one to predict the future of any of the processes4 ,lest the metallurgical facts scattered through several chapters escape1 let us summarize a little4 ,roughly speaking1 the capabilities of and materials required for the processes are as follows--the chemical symbols for silicon1 manganese1 carbon1 phosphorus1 and sulphur being used for brevity3 ,,process ,,refining ,,capability ,,material ,,required ,crucible ,process4 ,removes no metalloids1 ,very low ,si4 ,p4 ,s4 and but simply remelts4 ,c4 ,acid ,bessemer ,process4 ,takes out ,si4 ,mn4 and ,very low ,p4 and ,s4 ,c4 7under #j4a74 ,basic ,bessemer ,process4 ,takes out ,si4 ,mn4 ,c4 ,p4 ,very high ,p4 7#b and and some ,s4 over74 ,acid ,open-,hearth ,takes out ,si4 ,mn4 ,c4 ,very low ,p4 and ,s4 ,process4 7under #j4a of each74 ,basic ,open-,hearth ,takes out ,si4 ,mn4 ,c4 ,p4 ,wider ,variety4 ,process4 and some ,s4 ,electric ,furnace ,takes out ,si4 ,mn4 ,c4 ,p4 ,wider ,variety4 ,process4 and ,s4 ,in further explanation of the competition in quality of ,bessemer and of open-hearth steels it should be understood that in both the acid ,bessemer and the acid open-hearth furnaces we get out in quality just what we put in4 ,while for some purposes phosphorus and sulphur of #j4a per cent is allowable1 for other purposes they should not be over #j4jbe or #j4jc per cent4 ,to produce steel of the latter high quality1 material containing slightly less than this of sulphur and phosphorus must be charged1 and these are usually much higher in price than are pig iron and scrap containing greater percentages of these metalloids4 ,illustration3 ,,charging ,,floor ,,of ,,the ,,battery ,,of ,,gas ,,producers ,,showing ,,rocking ,,arms ,,for ,,gradual ,,feeding ,,of ,,the ,,coal ,where materials of #b4e to #c per cent of phosphorus are obtainable1 as1 generally speaking1 they are not in this country1 the basic ,bessemer should make as low phosphorus steel as does the basic open-hearth4 ,the great advantages of the basic open-hearth process1 then1 are that for it can be utilized a much wider variety of raw materials than is possible with the acid open-hearth or either of the ,bessemer processes1 and1 particularly that here1 at least1 the proper materials are readily available4 ,the fuels used vary1 of course1 according to what is most available1 considering quantity1 quality1 and price4 ,natural gas has been a favorite fuel1 as also has oil4 ,but in many localities natural gas never was available and in others which were thus blessed1 the supply has been exhausted4 ,by-product coke oven gas and tar are being experimented with with some success4 ,largely because of the great size of the open-hearth furnace solid fuel1 such as coal which can be used for puddling furnaces1 is not adaptable4 ,as far back as #ahci attempts were made to gasify coal by burning it to ash and utilizing the gaseous products for industrial purposes4 ,these attempts succeeded and the process has been brought to quite a high state of development4 ,there are to-day a large number of efficient types of 8gas producers0 which furnish gas for general industrial use and it is with this 8producer gas0 that a great deal of the steel nowadays is made4 ,while endeavoring to leave out of these articles most of the chemistry and as much of the technical detail as is consistent with clearness1 the chemistry of combustion and the 8gas producer0 is so interesting that it will be well to explain that carbon 7coal1 coke1 wood1 etc47 can burn either in one or two stages4 ,nearly every one has noticed the blue flame with which coal burns in the parlor coal heater or in other furnaces where little draft is used and most of us remember that the gas which is given off from such a fire has asphyxiated many who were unfortunate enough to be sleeping in a closed room1 when through insufficient chimney draft or a leaky stove some of the unburnt gas filled the room4 ,this gas1 which is carbon monoxide1 is labeled ,,co in books on chemistry4 ,it is the result of burning the coal with insufficient air4 ,chemically it is explained by the second of the chemical 8equations0 which follow4 ,the third equation explains the second stage of the burning which would occur were further air or oxygen admitted to the upper part of the furnace4 ,the usual one-stage combustion with plenty of air3 #a4 ,c 7carbon7 #b,o 7oxygen7 burns to ,,co#b 7carbon dioxide74 ,non-poisonous4 ,the two-stage combustion with insufficient air3 #b4 ,c ,o burns to ,,co 7carbon monoxide74 ,poisonous4 #c4 ,,co ,o burns to ,,co#b4 ,non-poisonous4 ,carbon monoxide asphyxiates by forming a chemical compound with the hmoglobin of the blood1 which therefore is prevented from supplying the body with the oxygen that is required for the sustenance of life4 ,carbon dioxide is no such poisonous product1 as may be inferred when we remember that it is the gas with which our carbonated waters are charged and which is so commonly served with ice cream in ice cream soda4 ,now in a gas producer1 by maintaining a sufficiently thick bed of glowing coal and admitting only such amounts of air as will produce mainly carbon monoxide gas1 a product of high burning value is obtained4 ,a kilogram 7#b4b pounds7 of carbon in burning from ,c to ,,co generates only #bdej calories or heat units1 whereas its complete burning to ,,co#b would give #hjhj calories4 ,so by conducting the carbon monoxide gas--the product of the first stage of the combustion--through brick-lined pipes to the furnace1 and in the latter by addition of air allowing it to burn to ,,co#b1 the greater amount of heat 7i4 e41 #hjhj minus #bdej or #efcj calories7 is evolved in the furnace4 ,of course1 some of this theoretical two-thirds which is in this way made available at the furnace is lost because a little ,,co#b is formed1 and always the nitrogen of the air used greatly dilutes the gas4 ,but there are gains1 notably the great heat which is carried over by the hot gas from the glowing bed of coal and that from the water-gas which is formed from steam used in the producer4 ,so1 all in all1 the gas generated in a 8battery0 of gas producers1 all of which discharge into one large main or header to maintain gas of average composition1 is quite a satisfactory fuel4 ,,chapter ,x ,,cast ,,iron ,from the preceding chapters we now know pretty well the place which cast iron occupies in the iron family4 ,in the chapters which have succeeded the one in which we discussed the blast furnace and pig iron1 every one of the products except crucible steel has been produced through some 8refining0 operation which greatly changed the composition1 structure and properties of the product4 ,cast iron is not the result of a refining operation in this sense of the word4 ,it is produced through simple mixing of pig irons of various compositions1 usually with some admixture of iron castings of similar composition which have outlived their usefulness in the industrial world and have been returned as scrap to be remelted4 ,when we say that cast iron is not produced through a refining operation1 it must not be inferred that no change in composition occurs during the remelting4 ,there is some change1 notably a loss through oxidation from the air blast of a little of the silicon and manganese4 ,aside from this there usually will be absorption of enough1 or sometimes more than enough1 carbon from the coke used in melting to make up for the carbon which is oxidized4 ,usually some sulphur also is taken up from the fuel4 ,there is1 however1 no such actual or intended alteration of composition through burning out of the metalloids as is necessary for the production of wrought iron and steel4 ,but from this we must not assume that the manufacture of cast iron for chilled rolls1 car wheels1 machine parts1 valves and fittings1 etc41 is an easy proposition4 ,as we will soon see1 accurate regulation is required of metal for proper depths of 8chill0 for rolls1 car wheels and castings which must have high resistance to wear4 ,too1 the metal for valves and fittings and other more or less complicated castings for high steam1 air1 ammonia1 water1 etc41 must be uniform1 of close grain1 strong1 yet soft enough to machine easily at the extremely high speeds which modern efficient tools and methods demand4 ,the production of the best metal for such work requires the use of properly selected materials1 judicious mixing1 and clever operation of the cupola furnace1 that the molten metal delivered to the foundry for the pouring of the molds may be hot and fluid and of the right composition for the particular work in hand4 ,illustration3 ,,sampling ,,cars ,,of ,,high ,,silicon ,,pig ,,iron ,it is always interesting and instructive to follow the materials through their course from the 8raw0 state to finished products1 and1 therefore1 we are going to take you on a little trip from the receiving yard of a firm making cast iron goods where we see the cars of pig iron just in from the blast furnace and where the materials are sampled and held pending analysis1 to the laboratory where the samples are analyzed1 then to the storage bins where the materials are unloaded1 and1 later1 with the weighed charges1 to the cupolas which convert them into molten cast iron of the proper composition and quality for high grade castings4 ,illustration3 ,,sampling ,,other ,,pig ,,irons ,pig irons of lower silicon content cannot be broken easily with a sledge but usually are thrown from a height across an iron block4 ,twenty years ago it looked as if the iron foundry would be one of the last strongholds of 8rule-of-thumb0 to give way to scientific methods4 ,it does not look so to-day1 though there are many foundries which yet buy and use their pig iron on the basis of fracture2 i4e41 the foundryman guesses by judging of the color and closeness of grain and other characteristics of fresh fractures of the pig irons how suitable they are for his purpose and in what proportion to mix them4 ,a skillful man can get fair results in this way only so long as he uses the small number of brands of pig iron with which he is perfectly familiar1 and even then there must be but little fluctuation in composition of the irons used and he must be allowed considerable latitude in the quality of the iron which he produces4 ,success by this method is even more difficult now than it was ten years ago1 for the advent of many new blast furnaces and their greater variety of products have made this rule-of-thumb mixing a much more uncertain matter than it formerly was4 ,machine-made pigs1 which are so generally on the market now1 give fractures which tell little regarding their compositions4 ,illustration3 ,,drilling ,,the ,,samples ,no oil or other lubricant is allowable and the drillings are taken up with a magnet that no sand or other impurity may get into the sample for analysis4 ,while some foundries still attempt to accomplish this difficult and sometimes impossible feat1 the majority are now applying more scientific methods to their manufacture of cast iron4 ,though the eye cannot tell surely from the fracture the composition or quality of the iron which is used in making up the charges1 chemical analysis does definitely give this information4 ,therefore1 every car of pig iron purchased by this firm is sampled and analyzed1 the composition of all other materials used in its mixtures is determined1 and1 irrespective of fracture1 which may or may not tell the truth regarding their composition1 the raw materials are charged with respect only to their actual content of the metalloids4 ,the resulting molten iron each day is analyzed to confirm the correctness of the mixture and to furnish analysis of the 8sprues0 which next day are to be used as a part of the day's charge4 ,physical test bars1 too1 are cast each hour or so1 and the tensile1 transverse strengths1 hardness1 shrinkage1 etc4 are accurately determined in testing machines and recorded4 ,in this way absolutely nothing is left to chance or to guess work1 and1 as you may surmise1 any slight deviation from the composition desired is shown at once and the mixture immediately changed to the extent necessary to bring the iron back to normal4 ,it is surprising within what narrow limits of variation compositions and physical properties can be held1 with furnace operations continually under such surveillance4 ,illustration3 ,,weighing ,,out ,,portions ,,for ,,analysis ,the finely divided mixed drillings are shaken from a thin-bladed spatula on to the balance pan4 ,drillings are added or taken off until the long needle attached to the beam of the balance swings over an equal number of divisions on each side of the center mark of the white scale in the middle4 ,accuracy is #a_/dec1jjj of an avoirdupois pound2 this is approximately the weight of the lead of a 8pencil mark0 one inch long4 ,as the basis for its cast iron1 many thousands of tons of pig iron are each year used direct from the blast furnaces4 ,the raw materials come in railroad cars or by boat4 ,the inspector who represents the metallurgical department enters each car and inspects the materials1 taking from each a representative sample for analysis4 ,in the case of pig iron this will be from four to eight half pigs1 it having been found by experience that these represent very well the contents of the car4 ,so each car of material is held without unloading until it has been determined by inspection and analysis that it is fully up to the specifications upon which the iron was purchased4 ,arriving at the laboratory1 the half pigs from each car are drilled1 equal amounts of the drillings being taken and mixed in an envelope which bears the name of the brand of iron1 the number of the car1 the date1 etc4 ,the sample pigs from each car are treated in this same way1 each car being treated individually4 ,the envelopes containing the drillings then go to the chemists4 ,frequently samples from fifteen or twenty cars of pig iron1 with as many other samples of various derivation1 are being analyzed at the same time for the four or six different constituents which it is necessary for the metallurgists to know and control in order that a highly satisfactory product may result4 ,though a hundred different determinations may be in progress at the same time1 spelling 8chaos0 in the mind of one not entirely familiar with the details of the work1 it will be interesting to single out and explain briefly how the samples are analyzed4 ,illustration3 ,,closer ,,view ,,of ,,the ,,weighing ,in such analytical work everything is based upon weight2 i4e41 constituents are determined and reported in percentages by weight4 ,in chemical laboratory work everywhere the metric system is used1 the cumbersome ,english system of weights and measures being practically impossible4 ,thus1 the metric system is the international scientific standard4 ,the unit taken is the gram1 which is equivalent to part of an avoirdupois pound4 ,one gram of pig iron drillings is such an amount as could be held on an ordinary ten-cent piece4 ,working with such small amounts of the sample1 exactness and skill are extremely necessary4 ,the balances used are necessarily very delicate--just as delicate as were the scales upon which the jeweler weighed your diamonds--you remember1 of course4 ,on these balances we can weigh an inch-long mark made by an ordinary lead pencil4 ,illustration3 ,,dissolving ,,in ,,acids ,this is done under a hood that the irritating fumes given off may be kept from the room4 ,as the results of the analysis have to be known inside of three or four hours that the cars may be quickly unloaded in order to avoid demurrage1 which is the penalty for holding cars longer than the allowable time1 separate portions of each sample are weighed out for determination of the silicon1 manganese1 sulphur1 phosphorus1 graphitic carbon1 and combined carbon4 ,these are necessary in order to determine that the iron is up to the quality specified in the purchase contract and also to provide for its most efficient use in the manufacture of iron castings4 ,the exactly weighed portions are put into clean1 numbered beakers1 which are small pieces of high grade glassware that will stand sudden changes of heat and cold4 ,some of these portions are dissolved in nitric acid1 some in hydrochloric acid1 others in combinations of acids4 ,in each case the drillings go into solution in the acids1 and after various treatments of boiling1 evaporating1 filtering1 etc41 well known to those of the chemical profession1 the desired results are obtained4 ,in some cases it is by actually weighing a constituent which has been filtered out and burned to ash of a constant known composition1 in others it is by comparison of color with standards of known composition1 and sometimes it is by other means4 ,illustration3 ,,filtering ,,silicons ,after evaporating the excess acid1 baking dry1 cooling1 and redissolving in weaker acid1 the silicon compound formed may be filtered out4 ,the iron and other soluble constituents1 now in solution1 pass through the filter1 which is of pure1 porous1 unglazed paper4 ,in all of this analytical work the chemist must take care to lose not one drop of the solution or one grain of the ash from the burned 8precipitate10 as the 8filtered out0 constituent is called4 ,the pig iron is always bought upon guarantee that it will contain a certain percentage of silicon--the element which in cast iron is known as a 8softener40 ,but this is not the only thing necessary in the iron that is purchased4 ,it must also show proper specified quantities of manganese1 phosphorus and carbon1 which also are very desirable elements in iron castings1 and as little of that undesirable element1 sulphur1 as possible4 ,therefore they pay in proportion to the content of silicon1 manganese1 phosphorus1 and carbon--and penalize the seller for sulphur4 ,illustration3 8,,burning ,,off0 ,,the ,,silicons ,the paper and contents1 in a little crucible1 are placed in a red-hot muffle furnace4 ,the paper is such pure cellulose that it leaves no weighable ash4 ,that which remains after burning is silicon oxide1 which is a perfectly white1 fine sand4 ,this is very carefully weighed4 7,ordinary sand is silicon oxide usually slightly colored with iron47 ,the laboratory holds copies of the contracts upon which these materials were bought4 ,if1 upon comparison1 the analysis obtained complies with the terms of the contract1 an ,o4 ,k4 unloading slip is made out and the receiving department is given directions into what raw-material bin in the receiver building it shall be unloaded4 ,if not fully up to the standard called for in the contract1 the purchasing department is notified and the car is either rejected or accepted upon some proper terms of adjustment if it can be used without detriment to the product in which it is to be utilized4 ,cars of coke1 limestone1 fluorspar1 etc41 are inspected1 analyzed and treated in the same way1 so that nothing is left to guess work4 ,the compositions as determined by the laboratory serve not only as the basis for acceptance or rejection1 but the analyses of accepted materials are forwarded at once to the metallurgists1 who from them figure the mixtures to be used in the cupolas4 ,having great stocks of analyzed raw materials in the labeled bins in the receiver building1 the metallurgists who supervise the mixing and melting of the iron determine by mathematical calculation just what irons and how much of each must be taken to give molten iron of the best composition and properties for the castings4 ,illustration3 ,,titrating ,,the ,,sulphur ,sulphur is evolved from the drillings as a gas 7hydrogen sulphide74 ,this is absorbed in a solution of chloride of zinc4 ,the amount of sulphur is measured by slowly running in from a burette a solution of iodine of very accurately known strength4 ,the iodine unites with the sulphur compound as long as any of the latter remains1 but the first drop added thereafter turns blue the whole solution because of the reaction of the excess of iodine with starch paste that has been added previously as an indicator4 ,accuracy is about 4#jje per cent of sulphur4 ,the total iron materials charged must have a definite amount of silicon1 of manganese1 of phosphorus and of carbon4 ,for a #d1jjj-pound charge for soft cast iron1 for instance1 the total silicon in the materials which make up the charge must be somewhere near #aah pounds1 the manganese and the phosphorus about #cj pounds each4 ,the usual losses of these materials through oxidation are known1 of course1 and sufficient excess has been allowed that the desired final composition will result4 ,illustration3 ,,titrating ,,phosphorus ,a yellow precipitate containing the phosphorus is filtered out on filter paper4 ,it is redissolved in alkali and titrated with a standard solution of nitric acid1 similarly to the sulphur4 ,the solution in the flask turns pink with the first drop added after the phosphorus has been measured4 ,on several scales which are regularly inspected and kept carefully adjusted1 the weighers weigh out the prescribed quantities of the raw materials4 8,buggies0 holding nearly one ton each are loaded in turn with coke1 with proper amounts of pig iron1 cast iron scrap1 sprues from the foundry castings of the preceding day1 and a proper weight of limestone flux4 ,each charge of two tons of iron requires four buggies for its transportation from the raw-material bins and scales to the cupolas4 ,the old-time way was for laborers to dump the charges into the cupola and spread the materials by hand1 but in modern foundries better ways have been provided4 ,here a charging machine operated by compressed air lifts into the furnace1 one by one1 the buggies of coke1 and of the other materials1 whence1 after the dumping of their contents1 the buggies are returned to the receiver building to be filled again4 ,thus many charges per hour pass through the yawning charging doors of the cupolas1 being dumped in fast enough to maintain the level approximately even with the bottom of the charging door4 ,illustration3 ,,reading ,,the ,,carbons ,the higher the combined carbon the darker the nitric acid solution of the iron or steel4 ,the solution is diluted with water or weak acid until the color matches that of a 8known0 sample or standard4 ,accurately graduated comparison tubes are used4 ,in starting1 a wood fire has been made on the sand bottom of the cupola4 ,this is covered with coke in such a way and in such amount that1 when ready for charging of the metal1 a column of glowing coke extends to a distance of one foot or two above the tuyres4 ,upon this 8bed0 in alternating layers are piled the weighed amounts of pig iron1 sprue1 scrap and limestone as described above4 ,following each charge is a layer of coke sufficient in amount to replace the 8bed0 coke which is burned away in melting the iron charge1 thus maintaining the top of the bed of coke throughout the day at approximately the same height4 ,illustration3 ,,weighing ,,the ,,graphitic ,,carbon ,the graphite is filtered out on an asbestos pad in a perforated platinum crucible4 ,after drying until all moisture is gone it is weighed1 ignited1 and weighed again4 ,the loss of weight equals the weight of the graphite of the sample4 ,ever since #g o'clock ,a4,m41 when the twelve to sixteen ounces of blast pressure was put on1 the charges have been descending gradually from the charging door4 ,encountering the intense heat in the 8melting zone0 at the top of the bed of coke a little above the tuyres1 the iron melts and trickles down through the three to five-foot bed of glowing coke on to the sand cupola bottom or hearth where it accumulates4 ,the tapper1 with his iron bar and 8bod stick0 with its little ball of moist fire clay1 alternately opens and plugs the tap hole at the bottom of the furnace as occasion requires1 but throughout the day of ten or more hours there is almost constantly a full stream of iron flowing from the spout4 ,the big 8bull ladle0 which receives it1 in turn gives it up to smaller or 8shank0 ladles1 in which it is conveyed along trolleys to still smaller ladles from which it is poured into the sand molds to form the castings4 ,illustration3 ,,another ,,close-,,up ,,view ,as in the blast furnace1 limestone is added as flux to make liquid and dispose of sand1 dirt1 scale1 etc41 which are detrimental4 ,the liquid slag formed from union of limestone with these impurities floats upon the molten iron in the cupola hearth1 as it is less than half as heavy as the iron itself4 ,it flows almost continuously from a higher hole called the 8slag hole10 in the rear of the furnace and just beneath the tuyres4 ,the slag has little value except as material for filling purposes1 etc4 ,so-called 8slag wool0 can be made by blowing air through it4 ,sometimes the blast from the cupola blows it in such a way that this pure white 8wool0 is formed and blows out of the slag hole of the cupola4 ,about ,christmas time some of the workmen take quantities of it home for decoration and for fireproof whiskers for 8,santa ,claus40 ,these operations go on continuously throughout the day1 each cupola making the particular grade of cast iron or 8semi-steel0 which is best adapted to the particular castings to be poured1 size1 shape and purpose of ,illustration3 ,,determining ,,carbon ,,by ,,direct ,,combustion ,in an electric furnace with pure oxygen passing over them1 the drillings burn as would splinters of wood4 ,from the gas given off the total carbon is determined with great accuracy4 ,illustration3 ,,weighing ,,pig ,,iron ,,for ,,the ,,cupola ,from three to six varieties of pig iron are used in each charge4 ,illustration3 ,,the ,,receiver ,,building ,here pig irons of different compositions are separately kept in numbered and labeled bins4 ,the magnet which is used for unloading and handling the iron may be seen4 ,the grab bucket for sand is at the right4 ,illustration3 ,,weighing ,,the ,,charge ,,of ,,coke ,close weighing is necessary1 for a variation of ten or fifteen pounds may affect the running of the cupola4 the castings being the three main determining factors4 ,illustration3 ,,sectional ,,view ,,of ,a ,,cupola ,when nearing the end of the day1 charging ceases1 the charging door is closed and the last charge1 gradually descending1 melts and flows into the bull ladle about an hour later4 ,as soon as the bull ladle is emptied it is run out of the way1 the cupola is drained of all iron and considerable slag through the tap hole1 and the bottom doors of the cupola are dropped by pulling from under them the 8props0 which have held them in position4 ,the great mass of bed coke follows with a great burst of heat1 light and flame4 ,this is quickly subdued with a stream of water and removed4 ,when cool1 the slag and accumulations are chipped from the cupola lining1 burned areas are patched with bricks and stiff1 fire-resisting mud1 the bottom doors are raised and fastened in position1 and the eight-inch sand bottom is packed in ready for the next day's run4 ,after building a fire and getting a good 8bed0 of glowing coke1 the cupola is ready again for the charging of iron4 ,illustration3 ,a ,,cupola ,,in ,,operation ,the stream of iron from the cupola spout flows into a 8bull ladle0 and from that into 8shank-ladles40 ,the bull ladle serves as a reservoir and mixer4 ,illustration3 ,,castings ,,of ,,cast ,,iron ,,as ,,they ,,come ,,from ,,the ,,molds ,the 8sprues0 have not been removed4 ,,chapter ,,xi ,,cast ,,iron 7,continued7 ,unlike the modern ,bessemer1 open-hearth1 and other steel products which are reworked1 i4e41 rolled1 forged1 etc41 cast iron is a comparatively old alloy dating back over several centuries4 ,it cannot be rolled1 forged1 or otherwise reshaped1 so its final form must be given to it at once by pouring or 8casting0 the molten metal into a mold4 ,its castings serve exceedingly well in the hundreds of places for which they are adapted4 ,they are comparatively cheap1 can be readily duplicated in small or large quantities1 and those from the softer grades of cast iron may be machined easily4 ,these cast iron alloys have only from one-third to one-half the strength of steel or wrought iron and are1 comparatively speaking1 very brittle4 ,where resistance to severe shock must be withstood they should not be used4 ,also1 some varieties have a 8habit0 of growing larger upon repeated heating and cooling4 ,this 8permanent growth0 is particularly noticeable when the alternate heating and cooling is at red heat or over4 ,pieces of cast iron have been made to gain #ae per cent in linear dimensions1 and it is quite common knowledge among machinists that a piece of cast iron which is slightly too small can be permanently expanded by heat4 ,nevertheless1 the cast irons have large and legitimate fields in which they are very serviceable4 ,from most of their important present uses they are not likely soon to be displaced4 ,illustration3 ,,because ,,of ,,their ,,large ,,size ,,molds ,,for ,,very ,,large ,,castings ,,have ,,to ,,be ,,made ,,on ,,the ,,floor ,,of ,,the ,,foundry1 ,,or ,,partly ,,in ,,pits ,cast irons in considerable variety of compositions and physical properties are available1 as was indicated by alloys ,nos4 #ad to #ai which were given in the table on page #hc1 part of which is here reproduced4 ,in alloys #c to #ac the carbon exerts the great influence on the physical properties1 and this is true also of the cast irons4 ,but all of the latter have a total carbon content of more than #b per cent1 and1 under certain conditions1 some of the carbon assumes a different form from that which we encountered in the steels4 ,this modified form is 8graphite10 well known to us as a flaky1 black1 greasy-feeling material1 which is soft and very fragile4 ,graphite in the iron alloy naturally weakens it and1 as it is itself such a good lubricant1 it makes cast iron machine easily if sufficient amount is present4 ,a ,,few ,,of ,,the ,,cast ,,irons ,silicon1,graphite1,combined ,total ,per ,cent,per ,cent ,carbon1 ,carbon1 ,per ,cent ,per ,cent ,no4 #ad4 ,white ,cast ,iron 4#gj 4#aj #b4fe #b4ge,very ,hard ,no4 #ae4 ,annealed 4#gj #b4gj 4#je #b4ge,machinable ,malleable ,iron ,no4 #af4 ,cast ,iron for #a4jj #a4jj #b4jj #c4jj,very ,hard ,chilled ,castings ,no4 #ag4 ,semi-steel #a4ge #b4hj 4#dj #c4bj,machinable ,no4 #ah4 ,gray ,cast ,iron #b4jj #c4aj 4#cj #c4dj,machinable ,no4 #ai4 ,soft ,gray ,cast #b4ej #c4cj 4#ae #c4de,machinable ,iron ,now1 the above must be understood as being typical compositions only4 ,there are1 of course1 irons of all intermediate compositions1 also1 and while the total1 graphitic and combined carbons1 typically1 are about as indicated1 there may be wide variation4 ,to illustrate what a variety of chemical and physical properties may be produced1 let us assume that the total carbon in a certain cast iron is #c4be per cent4 ,if this carbon is all in the chemically combined form 7i4 e41 combined with the iron to form the very hard compound which is known to the metallographist as 8cementite07 the fracture will be white and the alloy extremely hard4 ,if none of this carbon is combined1 but all is in the form of graphite flakes throughout the alloy1 the fracture will be 8gray0 and the alloy soft and machinable4 ,it is possible to produce either of these two conditions or practically any intermediate stage2 i4e41 we can almost at will split up the #c4be per cent of carbon into varying percentages of graphitic and combined carbon--the total always equaling #c4be per cent4 ,illustration3 ,no4 #cj4 ,,very ,,soft ,,cast ,,iron4 ,,note ,,large ,,graphite ,,flakes ,illustration3 ,no4 #ca4 ,,medium ,,hard ,,cast ,,iron ,the 8combined carbon0 is in the roundish1 dark parts4 ,it is the 8combined carbon0 that increases the strength of cast iron and steel4 ,the 8precipitation0 of graphite which is necessary for softness is brought about mainly through the influence of silicon1 which we before termed the 8softener40 ,other conditions being equal1 the higher the silicon 7if not above #d per cent71 the higher will be the graphite and the lower the combined carbon2 and vice versa1 the lower the silicon the lower will be the graphite and the higher the combined carbon4 ,it is mainly due to the 8combined carbon0 which is left after precipitation of the graphite that the alloy has greater strength1 hardness1 and closer grain4 ,so1 just as the steels are stronger and harder as the carbon increases 7in steel all the carbon is combined71 so1 other conditions being equal1 the strengths and hardnesses of the cast irons1 within usual limits1 increase as the combined carbon increases4 ,illustration3 ,no4 #ib;d4 ,,semi-,,steel4 ,a ,,closer ,,grained ,,and ,,yet ,,stronger ,,cast ,,iron ,illustration3 ,no4 #cc;e4 ,,mottled ,,cast ,,iron ,so-called because it is a mixture of white and gray iron4 ,just here it is interesting to remember that from the standpoint of metallography cast irons are simply steels in which there is what we might call an impurity or an adulterant1 graphite crystals4 ,it will be seen at once that could these graphite crystals be removed from the cast irons shown in photomicrographs ,no4 #gd1 ,no4 #ib;d1 ,no4 #cj and ,no4 #ca1 we would have alloys quite similar in appearance to the steels shown in photomicrographs ,no4 #c;b and ,no4 #bb;c which appeared on pages #gg and #gh4g ,footnote #g3 ,magnification #gj diameters4 ,illustration3 ,no4 #g4 ,,white ,,cast ,,iron ,so the softer cast irons which are used for valves and fittings1 machine parts1 radiators1 hollowware1 etc41 have high silicon4 ,parts that do not have to be machined can be of 8harder0 iron2 i4 e41 made of iron having lower silicon content4 ,manipulation of the silicon content is not the only method by which the hardness of cast iron can be influenced4 ,graphite can 8precipitate0 7i4e41 separate throughout the casting7 only if sufficient time is given it to do so4 ,that is1 the cooling of the casting after pouring must be sufficiently slow4 ,in a sand mold the iron remains molten for a time1 and after solidification it cools slowly enough that the greater portion of the carbon separates as graphite4 ,therefore1 castings of proper composition made in sand molds are soft and machinable4 ,if the iron is poured into a mold the surfaces of which are made of iron1 the molten metal upon entering becomes solid almost as soon as it takes the form of the mold1 and it cools with great rapidity4 ,under such conditions the carbon of the alloy is denied the time necessary to change into the graphitic form and the casting has a white fracture and is so hard that it cannot be machined4 ,illustration3 ,,section ,,of ,,chilled ,,car ,,wheel ,showing white iron rim4 ,there are many purposes for which the alloy should have extreme hardness and the great resistance to wear which accompanies such hardness4 ,the wearing faces of gears1 brake shoes1 rolls1 and car wheels1 for instance1 must be hard4 ,for such products1 white cast iron1 the extremely hard condition of the alloy1 just referred to1 is utilized4 ,such castings are usually produced with a white cast iron face1 but with a gray iron interior1 gray iron being less brittle and less likely to break under shock or strain4 ,a car wheel1 for instance1 has approximately an inch in depth of white iron on the surface which lies next to the rail on which it runs4 ,illustration3 ,,chilled ,,cast ,,iron ,the white edge resulted from the more rapid cooling against an iron chill1 as did the white rim of the wheel shown above4 ,such are known as 8chilled castings40 ,molds for them are usually made of sand1 with pieces of iron 7called 8chills07 imbedded where white iron is to be produced4 ,the molten iron next to the sand surfaces cools in the usual way and is gray and soft1 while that which lies next to the 8chill0 is white and extremely hard4 ,the 8depth0 of the chilled layer can be increased or diminished according to the thickness of the iron 8chill0 used1 its temperature1 and by the composition and temperature of the molten cast iron with which the mold is poured4 ,the sulphur and total carbon of the molten cast iron also have considerable influence on the depth of 8chill40 ,illustration3 ,,two-,,part ,,molding ,,flasks ,there is a cast iron alloy which is familiarly known as 8semi-steel40 ,it is simply a high grade and stronger 8gray0 iron and must be classed as a cast iron1 as our table on page #ahj shows4 ,while it could undoubtedly be made from materials which are commonly used for cast iron1 it is practically always produced by charging with these a certain amount of steel scrap to bring about the lower silicon1 phosphorus and total carbon desired4 ,illustration3 ,a ,,hollow ,,cylinder ,the casting which we are about to make4 ,because steel has a higher tensile strength than has cast iron1 many have inferred that it was the steel addition which made semi-steel stronger than the ordinary soft cast iron alloy4 ,the rather unfortunate name1 8semi-steel10 apparently was given because of the steel used and the intermediate strength which the resulting product possessed4 ,however1 during the melting down of the charge the steel scrap becomes molten and its constituents merge with those of the other iron materials charged4 ,we get out of the cupola1 then1 a mixture which1 disregarding the losses and gains due to the air of the blast1 the fuel1 etc41 is an average of the materials charged4 ,we1 therefore1 no longer have any steel1 but a cast iron which has a somewhat lower silicon1 phosphorus and carbon than the softer cast irons4 ,the greater strength of the alloy is due to its composition and only indirectly to the fact that steel was used in its production4 ,the physical properties of the steel charged have been entirely obliterated in the melting process4 ,illustration3 ,,split ,,pattern ,,of ,,wood1 ,,surface-,,coated ,,with ,,shellac ,,varnish ,this view that semi-steel only indirectly gets its increase in strength from the steel charged is confirmed by its structural appearance under the microscope1 as was shown in numbers #gd and #ib;d which were given on page #gi1 and the photomicrographs given here1 and by its extreme brittleness under hammer blows4 ,under such shock it is but little more resistant than cast iron4 ,illustration3 ,,core ,,that ,,makes ,,hole ,,in ,,casting ,this weakness under 8shock0 was shown by tests from which the table which follows was compiled4 ,bars one inch square and thirteen inches long laid on supports exactly twelve inches apart1 were struck at the center by a twenty-five pound weight4 ,it took seven blows to break the cast iron bar1 the semi-steel bar required eleven1 while cast steel withstood ninety-two blows4 ,even this does not adequately express the great resistance of the cast steel 7another alloy not yet discussed71 for the height of the 8drop0 was being increased one inch with every blow1 and the cast steel bar1 on account of its bending1 had to be regularly turned4 ,the total foot-pounds exerted by the blows are given in the table which follows3 ,illustration3 ,,drag1 ,,or ,,bottom ,,half ,,of ,,mold1 ,,after ,,pattern ,,is ,,withdrawn ,illustration3 ,,drag ,,with ,,core ,,in ,,place ,,and ,,cope1 ,,or ,,top ,,half ,,of ,,mold ,,ready ,,to ,,close ,illustration3 ,,transparent ,,mold1 ,,showing ,,relative ,,positions ,,of ,,core1 ,,casting1 ,,sprue1 ,,etc4 ,alloy ,tensile ,number,total ,strength of ,foot ,blows ,pounds ,cast ,iron #bc1djj #g #ajb ,semi-,steel #ce1jej #aa #bjf ,malleable ,cast ,iron#h #cg1adj #bb #a1ehj ,cast ,steel#h #gb1abj #ibaj1aab ,footnote #h3 ,on account of bending1 the malleable iron and the steel bars had to be turned several times4 ,semi-steel is a very close-grained alloy of ten or twelve thousand pounds per square inch greater strength than cast iron4 ,it is a most satisfactory material for medium and larger sized castings for which cast iron formerly was used4 ,illustration3 ,,cast ,,iron ,,tee1 ,,cock ,,plugs1 ,,and ,,return ,,bends1 ,,with ,,sprues ,,and ,,gates ,,attached ,did we say that cast iron was very brittle8 ,so it is1 comparatively speaking4 ,but just as the chemist will tell you that there are no substances which are absolutely insoluble1 just so does cast iron appear to be extremely brittle only when compared with the iron alloys of considerably less brittleness4 ,the three pictures of the hooped and twisted casting illustrate how unwise it might be to speak with absoluteness4 ,a few years ago the casting illustrated on pages #aij and #aib was brought to this country by a visitor to ,europe1 with an expression of regret that cast iron produced in this country did not have such qualities of elasticity as had cast iron made abroad4 ,whereupon1 without any change whatever in his iron mixture or cupola practice1 the superintendent of a well-known foundry made castings which were exact duplicates of that submitted4 ,the three photographs shown further on 7,figs4 ,a1 ,b1 ,c7 were of one of these castings4 ,the ability to bend without breaking is1 of course1 largely due to the shape4 ,illustration3 ,,plugs ,,and ,,wheels ,,as ,,they ,,come ,,from ,,the ,,mold ,occasionally as many as #bjj castings can be made in one mold4 ,illustration3 ,,type ,,of ,,molding ,,machine ,as a matter of fact1 such castings were not at all new in this country1 having been furnished by ,american foundries for electrical work for many years4 ,cast iron springs1 piston rings1 and many other articles of cast iron are regularly made1 which show such elastic quality4 ,we have said considerable about 8castings40 ,in general we know what castings are1 but in the minds of some there may be a little uncertainty as to the manner in which they are produced4 ,illustration3 ,,another ,,of ,,the ,,many ,,kinds ,,of ,,molding ,,machines ,there are few lines of human endeavor which require greater judgment and skill than does the making of molds for castings4 ,sound judgment based on long experience1 knowledge of conditions under which the work immediately in hand must be done1 observation1 and accurate1 deductive reasoning as to the causes of failure are absolutely necessary for success4 ,illustration3 ,,casting1 ,,which ,,because ,,of ,,its ,,length ,,and ,,small ,,cross ,,sections1 ,,requires ,,very ,,fluid ,,cast ,,iron4 7,,fig4 ,a7 ,in general1 molding may be said to be done in 8pit0 or on the 8floor0 for large work1 on the 8bench0 for smaller work1 or by 8machine40 ,pit1 floor1 and bench molding are applicable for production of castings of all sizes and descriptions and this general type which we might term 8hand molding10 is the form that has been practiced longest4 ,molding machines are more or less recent inventions which have enabled certain standard shapes and sizes of castings which are in sufficient demand to be produced in great numbers by unskilled workmen and therefore at less cost than is possible by the older hand method4 ,each design for casting may be said to demand individual treatment1 and the molder must select that method out of the many which alone1 perhaps1 can be successful4 ,the subject is such a broad one that little will be here attempted further than to give by description and illustration the predominant points of the making of molds and castings4 ,a simple1 typical case of bench molding will be taken1 that the relation of pattern1 mold1 core and casting may be clear4 ,the molding sands used are usually natural sands which contain greater or lesser amounts of clay1 which1 when moist1 acts as a 8binder0 of the grains of sand4 ,when used without drying1 the mold is said to be a 8green sand0 mold2 if dried1 a 8dry0 or 8baked0 mold1 as the case may be4 ,the majority are 8green sand0 molds4 ,for the usual casting of which only a few or several duplicates are wanted1 the 8split0 pattern is generally the most convenient4 ,the two halves of the mold1 the 8cope0 7top7 and the 8drag0 7bottom71 are separately made in the two parts of the 8flask0 or molding box by 8ramming0 properly selected and 8tempered0 7moistened1 mixed1 and sieved7 sand over the halves of the pattern4 ,of these1 the drag is made first over the lower half of the separable pattern placed flat side down upon a bottom board4 ,after 8ramming10 i4e41 packing the sand1 just hard enough but not too hard1 this half mold is reversed and the top half of the pattern placed upon the lower half1 now at the upper face of the drag and flat side up4 ,a little 8parting powder0 or fine1 dry sand is sprinkled over the fresh surface of the half mold so that the upper half1 next to be made1 will not stick to the lower half1 but can be lifted off at the proper time4 ,illustration3 ,,it ,,may ,,be ,,bent ,,double ,,readily ,,without ,,breaking4 7,,fig4 ,b7 ,the cope half of the two-part 8flask0 is now put on1 filled and rammed with sand as was the drag4 ,any extra sand is scraped off with a straight edge and at the proper place a hole is cut with the 8sprue cutter0 straight down through the cope to the 8parting40 ,more commonly1 perhaps1 this 8sprue0 hole is made by withdrawing a 8sprue0 stick 7of wood7 about which sand had been packed during the making of the cope4 ,it is through this hole that the molten metal will be poured into the mold4 ,illustration3 ,,because ,,of ,,its ,,ability ,,to ,,withstand ,,bending ,,and #ahj-;,,degree ,,twists ,,it ,,is ,,often ,,jocularly ,,referred ,,to ,,as ,,the 8,,rubber ,,casting40 7,,fig4 ,c7 ,lifting the cope or top half1 it is turned upside down1 and1 after cutting in the drag the 8runner0 or 8gate0 connecting the 8sprue0 hole with the casting1 the halves of the pattern are carefully drawn that the sand may not be disturbed4 ,now in the cavity left in the drag1 to make the hole in the casting1 is hung the baked 8core0 of sand1 held together by flour or rosin or a 8drying0 oil4 ,the cope is carefully replaced upon the drag1 thus 8closing0 the mold4 ,as will be noted from the drawings1 there is left between the core and the mold a space all around1 which will be filled by the metal of the casting when poured4 ,therefore the surface of the core shapes the inside1 and the mold itself the outside and ends of the casting4 ,the molten metal1 entering through the vertical 8sprue0 hole1 flows along the 8runner0 and into the mold through the more or less constricted entrance called the 8gate40 ,the gases formed during pouring and the air with which the mold was filled are driven out through the porous bodies of sand of the mold and core4 ,had the mold been rammed too hard the gases could not escape through the sand and an imperfect casting would result4 ,the poured mold is allowed to stand until the metal has solidified and cooled sufficiently1 when the casting is 8shaken out40 ,the sand is returned to the molder to be used again4 ,the sprue and runner are broken from the casting1 which1 after cleaning by 8tumbling0 with others in a revolving mill1 or otherwise1 goes to the machining and assembling shops4 ,some form of the above general method is everywhere used for the production of all kinds of castings1 except for those which can be made by machine at a lower cost for molds4 ,this kind of molding1 which we have termed 8hand work10 requires expert molders and is too slow and expensive for the hundreds of standard shapes and sizes of castings which are in great and constant demand4 ,the latter are made on cleverly devised molding machines working with compressed air or by hand power applied through a lever4 ,the pattern is attached to the machine1 set and very accurately adjusted by a skilled mechanic4 ,thereafter the sand is rammed1 the runner formed and the pattern drawn by the machine itself1 all of these very critical movements being therefore rapidly and unerringly duplicatable any desired number of times by unskilled labor1 which has but to put on the parts of the 8flasks10 feed in the sand1 set the cores1 close and remove the mold1 and begin the next4 ,sometimes there is but one1 but for the smaller sizes there are often ten or twenty1 and1 occasionally1 as many as two hundred pieces or castings in a single mold4 ,,chapter ,,xii ,,malleable ,,cast ,,iron ,it almost goes without saying that the capacity to withstand distortion without breaking was the meaning of and the reason for the use of the term 8malleable40 ,but wrought iron is malleable as also is mild steel1 and1 in ,europe fifty years ago 7though in general not now7 by the term 8malleable iron0 was meant and understood what we know as wrought iron4 ,you will remember that ,bessemer's paper announcing his great process was entitled 8,the ,manufacture of ,malleable ,iron and ,steel without ,fuel40 ,the first reference was to wrought iron4 ,bessemer did not succeed in making this by his process but his success in the manufacture of steel was immense4 ,therefore1 while in ordinary conversation such definiteness is not necessary1 perhaps1 and not usual here1 to be safe one should say 8malleable cast iron10 and not simply 8malleable iron10 for by the latter1 many ,europeans still understand wrought iron4 ,like 8,topsy0 of 8,uncle ,tom's ,cabin0 fame1 the various members of the iron family 8just growed40 ,therefore a strictly logical classification and nomenclature is hardly to be expected4 ,it was mentioned in a former article that a process for making malleable the brittle white cast iron was discovered1 or at least described1 by ,reaumur1 a ,frenchman1 about #agbb4 ,it is likely that his discovery or acquaintance with it came about through his extended experiments with cementation steel4 ,illustration3 ,,malleable ,,cast ,,iron ,,bars ,illustration3 ,,malleable ,,iron ,,castings ,the publicity which ,reaumur voluntarily gave to his researches forms a notable exception to the customs of those days when it was the usual thing for manufacturers jealously to guard all trade secrets4 ,these were handed down from father to son or to others of close interest in the business4 ,so aside from ,reaumur's announcements concerning malleable iron1 few details of its manufacture came to light during the eighteenth century4 ,even during the hundred years which have just passed there have been few lines in which greater secrecy has been maintained both in ,europe and ,america4 ,during the last thirty years1 only1 has real scientific work been done to make known the reactions which occur during annealing and the real causes of the malleability4 ,the father of malleable iron in this country was ,seth ,boyden1 of ,newark1 ,new ,jersey1 a very ingenious man who well deserves the monument erected in his honor by the citizens of the city1 which is pardonably proud of him4 ,illustration3 ,,test ,,sprues1 ,,showing ,,white1 ,,slightly ,,mottled1 ,,medium ,,mottled1 ,,and ,,gray ,,fractures ,boyden apparently had no knowledge of the existence in ,europe of the malleableizing process1 but after noticing that a piece of formerly brittle cast iron had become rather malleable1 apparently through the action of heat1 he set about making experiments to produce a malleable material which could be produced more cheaply than wrought iron4 ,by melting in a forge pieces of pig iron and then annealing in a small furnace in his kitchen fireplace the bars which he cast from the melt1 he had worked out by #ahbf a process that produced cast iron which was malleable4 ,in #ahca he started a foundry and made a thousand or more different articles for which there was demand1 and1 from this beginning1 an immense industry developed in this country4 ,illustration3 ,,test ,,bars ,,with ,,one ,,edge ,,cast ,,against ,a 8,,chill0 ,the composition of the mixture is regulated according to the depth of the chill as well as by appearance of test sprues4 ,we must not forget that the malleable cast iron as produced in this country is an entirely separate and distinct thing from the ,european malleable iron1 as will be shown later4 ,so our immense industry is our own and not a copied one4 ,it is only certain members of the cast iron family that can be made malleable by proper heat treatment4 ,alloys ,no4 #ad and ,no4 #ae represent one of these alloys before and after the annealing process4 ,while ,no4 #ad was given as a typical analysis for white cast iron for malleableizing it must be understood that compositions can vary considerably without detriment from that given4 ,there is one thing1 however1 which is absolutely necessary and that is that all or practically all of the carbon of the alloy must be in the combined form previous to the annealing process4 ,this means that the alloy shall be white cast iron and have no free graphite1 for any graphite flakes will remain through and after the annealing process and weaken the alloy just as it weakens gray cast iron4 ,illustration3 ,,sketch ,,of ,a ,,coal-,,fired ,,air ,,furnace ,for producing this white cast iron two processes are in general use--the 8cupola0 and the 8air furnace40 ,the latter predominates4 ,operation of the cupola for malleable iron requires great skill and very close attention to detail1 for1 to malleableize easily and with the best results1 the composition of the alloy must be regulated within narrow limits1 very much narrower than for gray cast iron4 ,however1 this is entirely possible and cupolas are operated continuously for malleable cast iron for ten or more hours with very slight fluctuation4 ,in general1 operation is very similar to that described for cast iron except that the composition of the charge is necessarily different1 much lower silicon being required1 and more coke has to be used for the melting4 ,most malleable iron castings are made in sand molds1 and1 as stated1 the iron poured must be of such composition and temperature that the castings so made will be white of fracture4 ,it is possible to get a quick indication of the condition of the iron for pouring by making test pieces1 every one in the same way1 which1 after cooling and breaking1 will show by fracture the approximate composition of the metal4 ,according to these test pieces1 called 8sprues10 which1 at times1 may be cast as often as every five or ten minutes1 the mixture is regulated to produce a uniform product4 ,illustration3 ,,firing ,,an ,,air ,,furnace ,to illustrate3 ,the fracture of a round sprue1 or test piece1 always inch in diameter1 when poured in the sand1 cooled there to low red heat1 quenched in water and then broken1 should be white with only a few flecks of dark constituent4 ,a gray iron fracture indicates too high silicon content and such iron is usually termed 8low0 iron4 ,castings of medium or heavy section1 which1 therefore1 cool slowly in the sand1 if poured of too high silicon1 i4e41 8low0 iron1 might precipitate a little graphite during cooling1 even though thinner-sectioned castings which cool so much more rapidly would come white from the same iron4 ,while iron giving nearly white sprues is necessary for particularly large castings1 to make sure that the usual run of malleable castings will come white in the sand requires very slightly mottled test sprues4 ,test blocks also1 with one side cast against an iron 8chill0 are poured to determine the depth of chilling1 and test bars of various shapes are regularly made1 to test after annealing1 for tensile strength1 torsion and other physical properties4 8,air furnaces0 are much like longer puddling furnaces4 ,they vary in capacity from ten to forty-five tons while occasionally small ones of as little as three or five tons capacity are met with4 ,illustration3 ,,taking ,,off ,,the ,,slag ,the usual fuel is soft coal4 ,the long flame passes from the grate at one end over the bridge wall and is deflected by the roof down upon the bath beneath4 ,a chimney at the outgoing end furnishes draft4 ,the furnace bed is usually of brick upon which is fritted 7slightly fused7 a mixture of sand with a little lime4 ,in order to facilitate charging of the materials to be melted the roof is usually removable in parts1 called 8bungs40 ,these have frame work of iron which hold in place the fire bricks that come in contact with the flame4 ,during charging these bungs are lifted off one at a time1 and the iron materials are dumped through the openings4 ,small doors in the sides just above the bath allow 8rabbling0 or mixing of the charge and skimming of the slag which forms1 and one or more spouts lined with fire bricks and clay provide for tapping out the metal when it is ready to pour4 ,illustration3 ,,tapping ,unlike puddling furnace and open-hearth no burning out of the silicon1 manganese and carbon is desired1 though1 of course1 some occurs and has to be allowed for in calculating the mixture4 ,the intention is simply to melt together with the least possible loss a mixture of such materials as will give the average final composition which long experience has shown to give the proper qualities to the finished product4 ,charges usually are of certain percentages of pig iron with not too much phosphorus1 sprues from previous melts1 more or less good malleable iron scrap and small amounts of steel scrap4 ,these are melted down as quickly as possible4 ,occasionally the slag which accumulates is skimmed off and1 after rabbling1 test plugs are poured from the fractures of which the composition of the iron is judged4 ,when the silicon content is deemed proper or has been adjusted through longer action of the flame if too high or addition of more silicon in the form of a high silicon alloy if too low1 the iron is tapped1 provided it is hot enough4 ,malleable iron is largely used for very small castings4 ,these require very hot and fluid metal4 ,so1 even if it is of proper composition1 the metal must be held in the furnace until it is of a high enough temperature to pour properly4 ,through prolonged and strong heating the iron may easily become oxidized or 8burnt0 and much skill is necessary for proper operation of the furnace4 ,after tapping1 the iron must be got into the molds with the least possible delay4 ,as has been mentioned with former processes the melting of iron in contact with coke or coal results in more or less contamination with sulphur4 ,for this reason cupola malleable has considerably higher sulphur than has malleable cast iron made in the air furnace4 ,cupola and air furnace each has certain advantages and certain disadvantages4 ,while strength and elongation are somewhat greater in air furnace than in cupola malleable1 both anneal well and give materials which are satisfactory for the purposes for which they are intended4 ,cupola metal has an advantage in that the temperature and the composition can be closely maintained the same throughout the heat1 perhaps more so than with the air furnace4 ,with the latter the metal at the top of the bath is hotter than that underneath1 and1 through action of the flame and air1 silicon is somewhat lowered before all of the heat can be poured1 especially with air furnaces of large size4 ,the metal can easily be 8burnt0 unless extreme care is taken4 ,in the cupola we can get very hot iron continuously so that it is unnecessary to prolong the heat with the danger of burning that occurs with the air furnace4 ,air furnace iron anneals rather more readily than does the product of the cupola1 and the strength and malleability are usually greater4 ,the former requires a temperature of about #acej ,f41 while the latter must have #aejj ,f41 a difference of about #aej ,f4 ,whether this results alone from the somewhat higher sulphur of cupola malleable is not definitely known1 but it is probable that1 also1 the slightly higher total carbon gives the iron-carbon chemical compound a tendency to persist more strongly4 ,the open-hearth furnace is sometimes used for making malleable cast iron4 ,it melts much more quickly than does the air furnace which requires from three and one-half to nine hours per heat1 depending upon the size4 ,the quality of the product which the open-hearth furnace produces is of the best1 but on account of the continuous operation necessary1 this type of furnace is not largely used4 ,malleable iron has also been made in the ,bessemer converter1 and1 occasionally1 in the crucible furnace1 but in this country the practice is not at all common4 ,in ,germany a great deal of malleable iron is made in the crucible furnace4 ,when dumped from the molds the castings are extremely brittle4 ,the sprues are knocked off and the castings go to the 8tumbling0 mills where they are tumbled1 either with the sprues1 with hard iron 7white iron7 shot or star-shaped pieces of iron which quickly clean the sand from them and give smooth1 clean surfaces4 ,at the chipping and sorting benches any remaining pieces of gates and other excrescences are removed while the castings are being handpicked and sorted4 ,white iron1 because of its brittleness1 breaks easily and small protruding parts can more readily and cheaply be removed before annealing than after the castings have been thereby toughened4 ,illustration3 ,,annealing ,,furnaces1 ,,showing ,,sets ,,of ,,pots ,,or 8,,saggers0 ,,in ,,which ,,the ,,castings ,,are ,,annealed ,having the cleaned castings of white iron of proper composition1 malleability is given to them by the heat treatment known as 8annealing40 ,through the influence of a cherry-red heat continued over a sufficiently long period the iron and carbon1 which in the white iron are chemically combined1 gradually become divorced1 and1 after complete annealing1 the casting will be found to consist of free iron in which are imbedded throughout very small particles of coke-like carbon4 ,castings that before this heat treatment were so brittle that they broke into many pieces under a blow and so hard that they might scratch glass1 are now found to be capable of withstanding considerable distortion without fracture and so softened that a needle may scratch them4 ,not only is a proper temperature necessary for best annealing1 but1 as stated1 a sufficient time must be allowed for the separation of the carbon and iron4 ,the separation requires many hours and the cooling from the annealing temperature must be slow in order that the carbon and iron may not again unite1 as they certainly would do were the castings chilled in water or otherwise cooled too fast4 ,most manufacturers produce tonnage enough that castings have to be annealed in quantity4 ,as iron at red or higher heat wastes very rapidly on account of scaling 7in fact would take fire in air if hot enough71 and the quality of castings deteriorates somewhat if even a small amount of air is allowed to come in contact with them during the annealing process1 they are generally protected by enclosing in iron containers on which tops are luted and cracks filled with stiff1 fire-resisting mud which keeps out the air4 ,these iron drums are of suitable size and shape that they can be stacked one upon the other to a height of from four to six feet4 ,the stacks or 8sets0 of 8saggers0 as they are called1 are run into large brick-lined retort chambers which are heated either with coal from a grate1 by powdered coal1 oil1 producer gas or other fuel4 ,the larger the furnace and the greater the tonnage of iron which must be heated1 the longer will be the time necessary for bringing the furnace and castings up to the cherry-red heat which is necessary for the annealing4 ,therefore1 the larger furnaces require a somewhat longer time than those of smaller size1 though the time required for the annealing of the castings themselves is no longer4 ,in this country with ordinary-sized furnaces the usual time for the annealing operation is approximately one week4 ,this includes the heating of the furnace and castings and the cooling to a black heat again4 ,illustration3 ,no4 #aji4 ,,photomicrograph ,,of ,,white ,,cast ,,iron ,some manufacturers1 however1 anneal without pots but they aim to have the castings protected from the flame and air4 ,illustration3 ,no4 #aaj4 ,,photomicrograph ,,of ,,no4 #aji ,,after ,,several ,,hours ,,of ,,annealing ,handling devices have been designed which facilitate loading and unloading the furnaces4 ,with these the many sets of pots or saggers which the furnace holds can be very quickly charged or removed4 ,after shaking the castings out of the cooled pots1 the dark coating is removed from them by 8tumbling0 with iron shot1 pieces of leather or other polishing material in tumbling mills after which they are ready for any machining which may be necessary4 ,photomicrographs ,nos4 #aji1 #aaj1 #aac and #ce which show the samples at #ge diameters magnification show the course of the annealing process4 ,no4 #aji was taken from an unannealed casting4 ,no4 #aaj was of the same iron after approximately thirty hours in the furnace4 ,no4 #aac shows that after about forty-five hours nearly all of the iron-carbon chemical compound has been broken down into black patches of free carbon1 surrounded by the white areas of pure iron4 ,after about sixty hours all of the iron and carbon have been divorced and the annealing operation is complete1 as is shown by photomicrograph ,no4 #ce4 ,illustration3 ,no4 #aac4 ,,photomicrograph ,,of ,,no4 #aji ,,when ,,nearly ,,annealed ,illustration3 ,no4 #ce4 ,,completely ,,annealed ,,malleable ,,cast ,,iron ,while heat alone effects the divorcing of the carbon and iron1 which is the essential part of the annealing process1 in the greater number of cases aid is given by what may be termed chemical means4 ,reaumur1 who about #agbb discovered the annealing process1 used iron oxide for the purpose4 ,the white iron was packed in iron ore or mill scale4 ,at the high temperatures employed the oxygen of the ore in some way not yet definitely known1 gradually removed the greater amount of the carbon from the casting4 ,it has always been a scientific conundrum how a solid1 iron oxide1 surrounding another solid1 a piece of white iron1 could remove from the latter its carbon when neither of them melts nor mingles with the other4 ,whether some of the oxygen from the ore penetrates the iron and burns out its carbon or whether the carbon of the casting itself migrates is not yet definitely settled4 ,certain it is that the carbon is gradually removed from the casting1 from the surface first and with increasing length of time from greater depths4 ,illustration3 ,no4 #cij;b4 ,,photomicrograph ,,showing ,,decarbonized ,,outer ,,layer ,the photomicrograph also shows that this casting was not fully annealed4 ,in ,european practice malleable iron castings are still malleableized in this way1 i4 e41 by burning out the carbon4 ,the castings are made as thin as possible and the annealing in 8packing0 7iron ore or mill scale7 is continued for from one to two weeks4 ,at the expiration of this time the castings have a white1 steely fracture which is entirely unlike the fractures of malleable iron castings which are made in this country4 ,photomicrographs of such malleable iron show few or none of the black spots which ,no4 #ce exhibits1 and analyses of castings annealed in this way give very low results for carbon4 ,illustration3 ,,malleable ,,cast ,,iron ,,in ,,which ,,practically ,,all ,,of ,,the ,,carbon ,,has ,,been ,,removed ,,by ,,reaumur ,,process ,,annealing ,while in this country the ,reaumur process of annealing is not followed1 a 8packing0 of ore or scale is generally used4 ,some use an inert packing such as sand1 and as first mentioned1 some use no packing at all4 ,really1 one of the main purposes of the 8packing0 as now used is the prevention of warping of the castings in the pots while annealing4 ,the annealing temperature is not so high as in ,europe nor is the annealing continued so long1 but when packing is used for the shorter time only1 some surface carbon is removed and the carbon throughout the center portions of the castings is precipitated in the coke-like form which is known as 8temper carbon0 to distinguish it from graphite which is shown in photomicrograph ,no4 #ce4 ,to the eye1 then1 fractures of such castings show black centers and white rims4 ,they are known as 8black heart0 castings and these form the bulk of the malleable cast iron made in this country4 ,illustration3 ,,fracture ,,of ,,black ,,heart ,,iron ,note the white rims and black coke-like interiors4 ,the majority of ,american malleable iron is of this 8black heart0 variety4 ,we may say1 then1 that there are in general three varieties of malleable cast iron3 the 8all black0 which is annealed without 8packing10 the 8black heart10 annealed in 8packing0 and the most common kind in this country1 and in ,europe1 but very rarely here1 the 8whiteheart0 from which practically all of the carbon has been burned during the 8anneal40 ,illustration3 ,,malleable ,,cast ,,iron ,,swivels ,,of ,,which ,,parts ,,no4 #b ,,are ,,cast ,,tightly ,,around ,,no4 #a ,,and ,,loosened ,,only ,,upon ,,annealing4 ,comparison of photomicrographs ,no4 #ce and ,no4 #cj given on page #aha1 will show at once one of the reasons for the much greater malleability of malleable cast iron4 ,while the total carbon present is very nearly the same in the two irons1 the difference in physical form causes great difference in the malleability of the two4 ,in the gray cast iron1 ,no4 #cj1 the carbon is crystalline and in the form of long brittle flakes which cut through and separate the grains of iron4 ,thus 8planes of cleavage0 are formed which make the alloy unable to resist severe shock and cause it to be anything but malleable4 ,it is not so with annealed malleable cast iron4 ,here the carbon is in the form of small pellets which are imbedded among the grains of pure iron1 the malleability of which is not seriously impaired largely because of the continuity of the 8pure iron0 structure4 ,a second reason for the ability of malleable cast iron to withstand shock is that in the burning out of the carbon of the outer portions of the casting very small cavities are left4 ,these allow the surface to become considerably deformed and battered under successive shocks without great strain on the casting itself4 ,nothing has been said so far concerning one trait of all of the irons and indeed of most metals and alloys which are used for casting purposes4 ,this is the tendency to 8shrink0 during the solidification and cooling of the metal of the casting4 ,on account of the freezing of the outer portions of the casting before the metal of the inside1 there must result certain hollow places or cavities after the inside metal has cooled unless some channel is kept open through which fluid metal can pass inside to keep cavities from forming4 ,we will not here go into the matter of shrinkage with its great worry to the molder nor the ingenuity and strategy through which he produces castings without shrinkage cavities4 ,one of the methods taken to overcome the trouble will be explained in the chapter on ,cast ,steel which is to follow4 ,there is1 however1 another type of shrinkage--that exhibited by the contraction of the entire piece of metal as it gradually cools after solidification4 ,this presents a rather curious and interesting case4 ,it is well known among founders and pattern makers1 that gray cast iron shrinks during cooling about inch per foot1 white iron inch per foot and cast steel inch per foot4 ,that is1 a bar cast exactly one foot long will be found when cold to be inch short if of gray cast iron1 inch short if of white cast iron and inch short if of cast steel4 ,the patterns have to be made larger than the castings desired to allow for this shrinkage4 ,but1 during annealing1 white cast iron loses one-half of its inch per foot shrinkage and the resulting malleable cast iron is found to have a net shrinkage of but inch per foot which is the same as that of gray iron4 ,it appears that the precipitation of the temper carbon expands the bar throughout to practically the same dimensions which it would have had if flake graphite had been allowed to precipitate through slow cooling1 as is the case with gray cast iron4 ,this is cleverly taken advantage of by manufacturers of swivels of malleable iron1 such as those shown4 ,the inner portions are separately cast first and thoroughly cleaned after which they are imbedded in another mold4 ,the outer portions are then cast around them1 shrinking so tightly upon the inner portions that they cannot be turned at all4 ,however1 upon annealing they loosen enough that they can readily be turned yet remain tight enough that they cannot be separated4 ,malleable iron from which the carbon has not been removed can be hardened and given a steely fracture by sudden cooling from a red heat even if it has previously been annealed4 ,decarbonized malleable iron1 also1 can readily be recarbonized by the cementation process4 ,these characteristics are often taken advantage of for the manufacture of tools from malleable iron4 ,hammers1 wood working chisels1 gears1 etc41 are quite largely made4 ,where they are sold at a cheaper price than the better steel tools and without misrepresentation1 there can be little objection1 but sometimes they pass for steel4 ,ofttimes malleable iron castings are made in what are known as 8permanent molds0 of iron4 ,they are really 8chilled castings40 ,annealing of these is accomplished in the regular way4 ,such castings have very smooth and beautiful surfaces but as the iron molds have high first cost they can be used only for castings for which the sales warrant the expense4 ,while much less malleable than is wrought iron or mild steel1 annealed malleable cast iron has considerable malleability4 ,it will resist great shock and can be severely battered and bent without breaking4 ,it has about #ge per cent or more of the tensile strength of mild steel and because of the cheapness of its castings the malleable iron industry has developed wonderfully4 ,about a million tons of this product are produced here each year4 ,naturally malleable iron castings are used where a material with properties intermediate between cast iron and steel will suffice4 ,such are castings for railroad cars1 for reapers1 binders1 and other agricultural machines1 pipe fittings1 and the cheaper grades of tools4 ,,chapter ,,xiii ,,cast ,,steel ,we have seen how primitive man hunted and fought with no implements and weapons better than clubs1 bows and arrows1 and stone hatchets1 and how his wife cracked and ground the corn between flat rocks or in mortars of stone4 ,in the succeeding 8,bronze ,age0 we found ornaments1 idols and tools being made of copper or the copper alloy1 bronze4 ,it was only after the next great advance that we found man utilizing iron for his purposes of civilization4 ,this metal1 which with us is so common1 was in those days very expensive1 so much so that it could be used only for purposes of war and as the gifts of kings4 ,but the world was traveling fast and it was not long before the iron-carbon alloy1 steel1 was produced4 ,even so1 many hundreds of years elapsed before the present wonderful age was ushered in through the great inventions of ,henry ,bessemer and the ,siemens brothers4 ,and while fine steels for swords and tools have had an incalculably great influence upon the development of the human race1 it was the mammoth production of ,bessemer and open-hearth steel which permitted its general use as a material for construction of ships1 bridges1 buildings1 and for railroads1 that made this the 8,age of ,steel40 ,speaking in terms of the power house1 it is also the 8,age of ,cast ,steel40 ,twenty-five years ago the manufacturer and power house man were quite content with their 8saturated0 steam temperatures and pressures4 ,with cast iron valves and fittings their plants were well equipped4 ,illustration3 ,,steel ,,castings ,,showing ,,the ,,risers ,,on ,,the ,,flanges ,castings for use on steam1 ammonia1 water lines1 etc41 must be of very close-grained metal and require much larger risers than castings for less exacting service4 ,but the world did not stand still4 ,it became known that by heating the steam out of contact with the water in the boiler it lost the moisture which it carried and became dry and then could be charged with as much additional heat as it was desired to give to it4 ,this 8superheated0 steam1 of course1 would do more work and it had also certain other advantages which the old-fashioned 8saturated0 steam had not4 ,but while cast iron fittings gave satisfactory service up to temperatures1 say1 around #dej ,f41 they faltered when forced to work under the new conditions which meant decidedly higher temperatures and pressures4 ,and1 too1 the repeated heatings and coolings which were often necessary1 disclosed a disadvantage previously unknown--a so-called 8permanent growth0 of the cast iron which was attended by loss of strength1 and altogether it was soon found out that when superheated steam was to be used1 higher types of materials were advisable than those which had been used under old conditions4 ,illustration3 ,,steel ,,castings ,,in ,,the ,,annealing ,,oven ,superheated steam has rapidly come into general use4 ,some of the new locomotives and most of the modern power plants are now built for as much as #bjj superheat1 i4e41 a total temperature of approximately #fjj ,fahrenheit4 ,valves and fittings of cast steel not only are the articles 8de luxe0 for such service but they have come to be considered the necessary articles and their advantages have only fairly begun to be appreciated4 ,though our most august scientific societies are proposing and debating upon systems of classification which shall include and satisfactorily define all of our ferrous metals1 a satisfactory one has not yet been evolved1 and1 considering the intricacy of our ferrous metallurgy and the discoveries which are being made almost daily1 the outlook for a strictly logical classification is not yet flattering4 ,with 8,cast ,steel0 our metallurgical nomenclature is again faulty4 ,before what we now call the 8steel casting0 was known1 crucible steel was poured into ingots1 8forged0 into tools just as it now is and often went under the name 8,cast ,steel0 to distinguish it from the contemporaneous material1 wrought iron4 ,so to-day we buy many tools and implements which bear the name cast steel1 which we know to have been forged in bringing them into their final shape4 ,but it is not these which we mean by the term1 cast steel1 but rather those steel products which get their final form by being 8cast0 from a fluid condition into a mold4 ,these are what are rapidly coming to be understood when the term 8cast steel0 is used4 ,satisfactory metal for steel castings may be made in any of three or four types of furnaces1 but1 as was suggested before1 the making of molds for castings is a fine art1 as is the preparation of the metal which is to go into them4 ,further1 the making of that special class of castings which are to withstand water1 steam or air pressure is a very different thing from the making of steel castings for other purposes1 and this is too often forgotten4 ,for the former are necessary particularly close-grained castings1 free from flaws or spongy spots4 ,under the great pressures applied such defects would certainly allow leakage4 ,illustration3 ,,flanges ,,and ,,fittings ,,of ,,cast ,,steel ,whatever the method of production of steel for castings the metal is poured into molds to receive its final shape4 ,because of the intensely high heat of the steel only sands of great refractoriness 7resistance to heat7 can be used as material for the mold4 ,white silica sand is such a material and is generally used1 mixed with enough clay and molasses-water to give it 8bond40 ,while molds for some steel castings are made in 8green0 7i4e41 undried or unbaked7 sand1 baked molds are preferred for fine finish and surest results4 ,after the making of the molds in the usual way they are sprayed with very finely powdered white sand or quartz mixed with a little molasses-water4 ,they are then thoroughly dried in an oven4 ,cast steel shrinks during cooling even more than malleable iron and the pattern and mold must be made to allow for this4 ,upon the freezing of the surfaces of the casting with consequent attainment of rigidity1 the interiors1 which freeze last1 may have cavities unless means for avoiding them is provided4 ,for this purpose heavier pieces1 which later can be cut off1 are cast upon such parts of the casting as tend to have 8shrink holes40 ,these may be likened to receptacles filled with fluid metal1 which being larger than the parts of the castings which they 8feed10 hold excess metal in fluid condition until the casting itself has become solid throughout4 ,such are usually called 8risers0 or1 in ,europe1 8lost heads10 and the molten metal in them flows down into the interior of the casting and fills the shrink holes which are forming4 ,not only must the risers be large enough that the metal in them is the last to solidify but they must be built high enough above the casting that sufficient pressure is exerted on the steel entering the shrinking parts to make its entry sure4 ,illustration3 ,,grain ,,of ,,steel ,,castings ,,as ,,they ,,come ,,from ,,the ,,mold ,illustration3 ,,grain ,,of ,,steel ,,castings ,,after ,,annealing 7,magnification #fj diameters7 ,baked molds1 of course1 are comparatively rigid4 ,as the risers which stand on top of the flanges and other high parts of castings aid in resisting the natural shortening of long castings during and after 8setting0 of the metal1 there is great liability that the still red-hot casting will crack somewhere along its length4 ,it is therefore necessary to loosen with bars the sand of the mold as soon as the metal of the casting has set1 particularly between the risers1 and to break out the sand of the core inside1 around which the shrinking metal might crack were the sand left in its hard packed condition4 ,after the casting is shaken out from the mold1 it is cleaned and the risers cut off either by sawing or with the more modern oxy-acetylene torch flame4 ,illustration3 ,,other ,,typical ,,steel ,,castings ,steel castings should be annealed in order to 8refine10 i4e41 make finer the grain of metal and to equalize 8strains0 which are set up in the castings during cooling4 ,coarse grain and internal strains tend to make the castings brittle4 ,no such extended annealing1 however1 is necessary as is the case with malleable cast iron1 for no divorcing of carbon from the iron with separation of free carbon is possible4 ,the castings are carefully heated to a temperature of about #afjj or #agjj ,fahrenheit and allowed to cool slowly4 ,after annealing1 they are cleaned and excrescences removed by chipping1 after which the castings are tapped1 drilled or otherwise machined according to the purposes for which they are intended4 ,illustration3 ,,cast ,,steel ,,valves1 ,,steam ,,separator1 ,,and ,,direct-,,return ,,trap ,,for ,,use ,,with ,,superheated ,,steam ,while more costly in manufacture and installation than are those of cast iron1 valves1 fittings and other cast steel products are1 so far as we now know1 practically permanent4 ,their notable shock resisting quality is well shown in the following table which is reprinted from page #ahh4 ,illustration3 ,,pouring ,,steel ,,into ,,molds ,,from ,a ,,bottom-,,pour ,,ladle ,it is to be noted that while malleable cast iron far surpasses 8semi-steel0 in this property1 though their tensile strengths are ordinarily somewhere near the same1 cast steel1 in turn1 offers more than six times the resistance of the malleable iron to shock and has nearly double its tensile strength4 ,it is this great strength and resistance to shock1 heat and pressure1 with freedom from 8permanent growth0 under alternate heatings and coolings that make cast steel such a valuable material for the many purposes for which castings are to-day employed4 ,millions of steel castings annually find varied application4 ,alloy ,tensile ,number,total ,strength of ,foot ,blows ,pounds ,cast ,iron #bc1djj #g #ajb ,semi-steel #ce1jej #aa #bjf ,malleable ,cast ,iron #cg1adj #bb #a1ehj ,cast ,steel #gb1abj #ibaj1aab ,in modern power houses and other commercial steam and hydraulic installations particularly1 steel castings have come to be the materials usually specified and approximately the only ones which satisfactorily serve under the severe conditions of to-day4 ,illustration3 ,,pouring ,,from ,a ,,lip-,,pour ,,ladle ,undoubtedly the first steel castings were poured from crucible steel1 though we must remember that the crucible is a melting and not a refining furnace4 ,this was only natural4 ,in the crucible the metal can be made very hot and fluid1 and if of proper composition and properly 8killed0 crucible steel makes very fine castings4 ,crucible steel castings1 however1 are not in as fortunate a position as are other products of this high grade material4 ,tool steels ordinarily bring high enough price that there remains a profit to the manufacturer though his manufacturing cost is necessarily high4 ,in the steel casting line1 however1 there is much keener competition and crucible steel has had considerable difficulty in maintaining its place4 ,it seems to be a matter of price alone4 ,open-hearth steel is very largely used for steel castings1 more than two-thirds of all made in this country being of this material4 ,about one half of these are poured from basic open-hearth metal1 and the other half from acid metal4 ,it is generally considered that the product of the acid-lined furnace is a little freer from over-oxidation4 ,illustration3 ,,tapping ,,side ,,of ,,two-,,ton ,,oil-,,burning ,,open-,,hearth ,,furnace ,,for ,,steel ,,castings ,open-hearth steel cannot generally be as hot and fluid as are the steels made in other types of furnaces4 ,for this reason as well as because of the larger size of the usual open-hearth furnace1 small castings are not generally poured from this steel4 ,it is for steel castings of considerable size and where there are sufficient orders to warrant a steady and large output that the open-hearth has its place4 ,true1 smaller open-hearths are now built1 some of them of only two or three tons capacity1 but1 in general1 the standard open-hearth for steel castings is of fifteen tons or more capacity and of the style of the open-hearth furnaces which were described in ,chapter ,,ix4 ,in their proper sphere they are highly satisfactory1 but they are 8inelastic0 in that they must be run continuously day and night and should not be allowed to cool until extensive repairs are imperative4 ,it was mentioned that in the open-hearth process the furnace is always hotter than the metal which it contains and that the heat which can be put into the steel is limited by the ability of the refractories of which the roof and side walls are made to withstand melting4 ,in the ,bessemer process the metal is hotter than the furnace because the heat is generated by combustion of certain of the metalloids contained in the metal itself4 ,as metal for castings must be very hot and fluid the ,bessemer process is very satisfactory for the making of steel for castings4 ,illustration3 ,a #cj-,,ton ,,basic ,,open-,,hearth ,,furnace ,,tapping ,the overflow from the ladle into the pit is slag4 ,it has1 also1 the advantage of 8elasticity40 ,the supply of metal is practically continuous and one furnace can make from one to eighteen or even more heats on day turn only and be shut down for the night turn or longer and then started again without such loss as would result from the shutting down of an open-hearth furnace with regenerators4 ,for the making of metal for steel castings1 very small-sized ,bessemer converters are used which make from one to three tons of metal per blow4 ,some converters of as little as one-half ton capacity are being used4 ,while some are of the 8bottom-blown0 type already described1 the majority are what are called 8surface-blown0 or 8side-blown40 ,in these1 from four to eight round tuyres1 about one and one-half inches in diameter each1 pierce the brick or ganister lining just above the surface of the bath4 ,they slope downward a little toward the bath so that when the converter is tipped to its upright or blowing position the air blast will strike the adjacent edge of the metal and blow across its surface4 ,this three or four pounds per square inch of air blast keeps the metal in circulation1 meanwhile burning out its silicon1 manganese1 and carbon1 just as it does in the larger bottom-blown converters4 ,surface-blown give hotter metal than do bottom-blown converters and very fine steel castings are made from their metal4 ,for these converters1 which are practically all acid-lined 7i4e41 with silica or clay brick or ganister71 metal low in phosphorus and sulphur is regularly drawn from a cupola specially run for the purpose4 ,illustration3 ,,small ,,side-,,blown ,,converter ,,making ,,steel ,,for ,,castings ,the remaining recognized type of furnace for steel for castings is the comparatively new electric furnace4 ,commercial melting of metals by the electric current has been sought for half a century4 ,in #ahgi the first furnaces of promise were patented by ,sir ,william ,siemens1 one of the ,siemens brothers who became so well known through their great work with the open-hearth furnace1 the gas producer and many other things metallurgical4 ,while ,siemens melted as much as twenty-two pounds of iron per hour in his furnace1 the cost of the electric current at that time was so high as to be practically prohibitive for the manufacture of steel in competition with the open-hearth1 ,bessemer and crucible processes4 ,illustration3 ,,drawing ,,of ,,side-,,blown ,,converter ,,in ,,blowing ,,position1 ,,showing ,,edge ,,of ,,metal ,,even ,,with ,,row ,,of ,,tuy,,res ,little of great moment in the electric furnace line developed during the nineteen years which followed4 ,then1 in #ahih1 ,stassano in ,rome1 ,italy1 constructed a furnace in which three carbons gave an electric arc above the surface of the bath4 ,about the same time1 ,heroult1 a ,frenchman1 was developing the electric furnace which to-day has become so well known in this country1 and which bears his name4 ,other well known furnaces of the arc type are the ,gronwall-,dixon1 the ,snyder1 the ,girod and the ,rennerfelt4 ,in general1 electric furnaces have more or less round steel shells with shallow brick1 magnesite or sand-lined hearths1 and sidewalls and removable roofs of brick4 ,heat1 of course1 is furnished electrically4 ,in most of them long carbon electrodes are lowered through holes in the roof until the lower ends strike an arc with the metal on the hearth4 ,the number of carbons may be from one to four or more depending upon the style and size of the furnace and the manner in which electrical connections are made4 ,all of the furnaces mentioned have been used for the production of steel for castings and the ,heroult and ,girod are in use in larger sizes for electric steel for rails and miscellaneous products4 ,the steel is first cast into ingot molds and is later rolled down into bars1 rods1 etc4 ,illustration3 ,a ,,gronwall-,,dixon #e-,,ton ,,electric ,,furnace ,,tapping ,illustration3 ,,first ,,experimental ,,arc ,,electric ,,furnaces ,,patented ,,by ,,sir ,,william ,,siemens ,,in #ahgi ,all of the above use carbon electrodes and are known as 8arc0 furnaces4 ,there is a distinctly different type of furnace which1 also1 is in use in commercial sizes4 ,this is the 8induction0 furnace4 ,in this1 what is known to electricians as a secondary current is 8induced0 in the bath itself and heats the metal4 ,of this type the ,kjellin and the ,rochling-,rodenhauser are the best known in this country4 ,while they are in use in the larger sizes for production of steel for ingots1 these two furnaces do not seem to have been used to any extent for metal for steel castings4 ,the details of construction of the furnaces which are used for metal for castings are more or less different1 but they are not of particular interest to us4 ,the working of all is similar and a general description should suffice4 ,illustration3 ,,drawing ,,of ,,the ,,snyder ,,electric ,,furnace ,illustration3 ,,small ,,snyder ,,electric ,,furnace ,,tapping ,whether starting with furnace cold or hot1 materials in molten or in the more usual 8cold0 form are charged on the shallow hearth of the furnace4 ,the charging doors are closed1 the current is turned on and the carbon electrodes are lowered until an arc is struck between the upper electrodes and the metal on the hearth1 which in some way is made to connect with the negative electrodes4 ,in one or two of the types mentioned the arc plays between the carbons1 all of which are above the bath4 ,at first there are great fluctuations in the current intensity because of the uneven surface presented by scrap steel on the hearth4 ,in a short time1 however1 the current steadies4 ,the intense heat of the arcs soon brings cold steel to a molten condition4 ,occasional attention from the attendant is necessary to see that the melting is even and that any outlying pieces of steel are pushed to the center where they must melt4 ,illustration3 ,,sketch ,,of ,,the ,,heroult ,,three-,,phase ,,electric ,,furnace ,there are three electrodes1 all of them above the bath4 ,only two show here4 ,in the basic-lined furnaces lime is usually charged with the cold steel4 ,with the iron oxide which is added from time to time this forms a highly oxidizing slag1 which1 after it takes the phosphorus from the metal1 is skimmed off4 ,as you will remember1 the other processes stop at this point1 little further refining being possible4 ,in the electric furnace1 however1 the sulphur1 also1 can be reduced to almost any desired amount by use of a further addition of lime1 and greater heat4 ,not only can the sulphur be reduced to very small percentages but the over-oxidized bath can be brought to neutral condition and the green or black slag made white with return of its manganese and iron to the bath4 ,this is accomplished by addition of small amounts of powdered coke or coal4 ,the whole process is under very accurate control4 ,with a practically white slag1 which is the signal that the deoxidation of the bath is complete1 and the sulphur reduced1 the steel is ready to pour provided it is hot enough4 ,tests of this are usually made either by pouring a little of the steel from a small ladle and observing its fluidity or by observing the quickness with which the end of an iron bar is melted off when plunged into the metal in the furnace4 ,illustration3 ,,the ,,heroult ,,electric ,,furnace ,of all the metallurgical steel furnaces1 the electric furnace is the most susceptible of accurate control4 ,with the heat applied directly to the metal in the cleanest way possible1 i4 e41 without the admission of coal ash or gas or air of the blast1 the atmosphere in the tightly closed electric furnace can be made 8oxidizing10 8neutral10 or 8reducing0 at will4 ,the metal can be held in the furnace and additions made1 samples taken1 and the operations conducted with regulation and certainty4 ,this newly devised metallurgical apparatus is coming to be largely used in the production of tool steels4 ,while it has not displaced the crucible method for the production of steels of the very highest qualities1 it has proceeded far enough in this direction in the very limited number of years since its introduction1 that it is certain that the crucible1 even for tool steels1 is to have a keen competitor4 ,tool steels in considerable variety are to-day being quite satisfactorily made in the electric furnace and it is not at all unlikely that steels of the very highest grade will shortly be produced by this method4 ,,chapter ,,xiv ,,the ,,alloy ,,steels ,we have learned that steel1 fundamentally1 is an alloy of iron with carbon1 i4e41 carbon is the characteristic element4 ,we are now to note what often seem to be exceptions to this rule4 ,while in reality steel is just this iron-carbon alloy1 there are alloys known as steels to which such strong characteristics are given by elements other than carbon1 that carbon seems not to be the defining constituent at all4 ,indeed1 in some of these1 the carbon content may be small enough that1 judging from our experience with the carbon steel series1 we would not expect any such physical properties as some of these alloy steels show4 ,you remember that in olden days they distinguished between wrought iron and steel by quenching the piece in water from a cherry-red heat4 ,if the piece was hardened and made brittle1 by this treatment1 it was thereby proved to be 8steel40 ,also1 it is generally known that by annealing a piece of hardened steel1 which usually means holding at a cherry-red heat for a time and then cooling slowly1 it is made soft4 ,then what shall we say concerning a certain one of these new alloys1 ,hadfield's manganese steel1 which is made very much less brittle and a little softer by quenching1 but which refuses absolutely to soften under annealing treatment--in other words1 is almost the opposite of what we know as steel in these chief defining traits8 ,the nickel steel which contains #ae per cent of nickel1 also1 exhibits just these characteristics1 being softened by quenching but not by annealing4 ,again1 while iron1 the carbon steels1 and even the magnetic oxide of iron which contains only about #gb per cent of the metal1 are strongly magnetic1 manganese steel which has #he per cent of iron is so non-magnetic that it is sometimes used in place of brass or bronze where an entirely non-magnetic material is required4 ,the nickel steels with #bd per cent or more of nickel are also non-magnetic though both constituent metals1 alone1 are strongly attracted by the magnet4 ,these are some of the things which make a logical classification of the iron family so difficult4 ,though derived from the steels which we knew and made from the same materials with the exception that a greater amount of one constituent1 manganese1 is added1 or perhaps1 in other cases1 another element or two1 the resulting alloys have markedly different and often contradictory properties4 ,however1 we must not be led astray4 ,in all probability carbon is still the necessary constituent1 but much less of it is needed to produce results when the other elements are present4 ,there is no doubt1 however1 that in 8manganese steel0 or in 8nickel10 8chrome10 8tungsten10 8silicon10 8vanadium10 8titanium10 and other alloy steels1 the added element or elements exert very strong modifying influences1 and sometimes obscure the influence of the carbon4 ,in the first place1 we better at once dispose of certain of these steels by terming the added element a 8scavenger0 only4 ,such usually are 8titanium0 and 8aluminum0 steels4 ,these are generally ordinary carbon steels in which a very small amount of titanium or aluminum has been used to rid the alloy of certain gaseous or other deleterious elements4 ,upon analysis1 steels so treated often show no trace of the element which has been added to do the work1 all of it having passed into the slag1 carrying with it the obnoxious substances1 which1 had they remained would have injured the quality of the steel4 ,manganese and silicon which were spoken of in the discussion of the ,bessemer process as deoxidizing the metal1 also exert just this same influence1 though there is usually added of these enough that a certain percentage remains in the finished steel4 ,vanadium and titanium have a particular affinity for oxygen and nitrogen1 and aluminum for oxygen4 ,by chemically combining with these gases in the metal1 and through possible other influence1 they help to produce sound steel having very good physical properties4 ,vanadium1 however1 is much more than a 8scavenger0 as will be seen later on4 ,manganese ,steel ,manganese steel was discovered and highly developed by ,robert ,hadfield of ,sheffield1 ,england1 along about #ahhb4 ,his #aa per cent to #ad per cent manganese steel with about #a per cent of carbon has such great hardness that it cannot be drilled or cut with tools4 ,in forgings and castings it is used for milling machinery for ore treatment2 manganese steel rails inserted around sharp curves and for 8frogs10 etc41 under severe service conditions outlast ordinary steel rails three or four times2 it goes into various rolls and crusher parts1 steam and dredge shovels1 grab buckets1 sand pumps1 gears1 pinions1 etc41 which have to resist heavy wear4 ,it is much used1 too1 as a material for burglar-proof safes4 ,the alloy is far too hard to drill and too tough and strong to be broken4 ,it is said that no manganese steel safe has ever been drilled or forcibly entered4 ,in forming irregular shapes1 manganese steel must be cast and finished by grinding but for ordinary bars and rails it can be rolled4 ,in the 8raw0 condition it is quite brittle and extremely hard4 ,quenching from a cherry-red heat greatly toughens it and makes it ductile4 ,though now it can be dented by a hammer blow and marked with a file1 it always is so tough that it cannot be machined with any tool4 ,ordinary annealing treatment has no softening effect on the alloy4 ,silicon ,steels ,when alloyed in the steel in certain quantities1 silicon gives desirable properties4 ,steels with from one to two per cent of silicon in the tempered condition are very tough4 ,for this reason the leaves of automobile springs are often made from it4 ,steels with from #c to #e per cent of silicon are much used in electrical appliances because of their improved magnetic properties4 ,molybdenum ,steels ,to a certain extent steels containing #c or #d per cent of the metal molybdenum1 and #a or #a per cent of carbon are used in the construction of permanent magnets4 ,it is said that molybdenum is used in some modern guns1 which longer resist the corrosive effect of the powder-gases because of it4 ,a certain amount goes into the high-speed steels where it replaces part or all of the tungsten4 ,here1 however1 it has been a disappointment and the amount so used seems to be decreasing rather than increasing4 ,tungsten ,steels ,steels with about per cent of each of carbon and tungsten are occasionally used for manufacture of springs1 and with greater amounts1 e4g41 per cent of carbon and #e or #g per cent of tungsten1 for permanent magnets for which they are claimed to be the best material known4 ,the use of tungsten in the tool steels 7other than the high-speed steels7 is considerable4 ,nickel ,steel ,nickel steel is much used on account of its high strength4 ,the most usual alloy1 perhaps1 is the one which contains about #c per cent of nickel4 ,this is in addition to the carbon which may vary between 4#ae per cent and per cent4 ,this #c per cent of nickel adds several thousand pounds per square inch in strength to the steel1 and when tempered1 both the strength and toughness are greatly improved4 ,nickel steels of these compositions can readily be forged and rolled4 ,they are used for drop forgings1 machine parts1 engine and automobile parts1 in seamless tubes and for bridge members of great span4 ,nickel will not rust so it does not surprise one that with #bb per cent or more of nickel the steel is almost immune from ordinary corrosion4 ,steels containing from #be to #df per cent nickel are variously used for resistance wire1 for valve stems1 valves for motors1 etc4 ,the #cf per cent nickel steel is the alloy1 8,invar10 which has such slight expansion and contraction with heat and cold that it is used for clock pendulums1 watch parts and for parts of measuring instruments4 ,forty-six per cent nickel steel is called 8,platinite40 ,it has practically the same rates of expansion and contraction with heat and cold as glass and for this reason it finds extensive use in incandescent electric lamps4 ,wires of the alloy are fused into the glass bases and connect with the filaments in place of the expensive platinum which formerly was used4 ,as remarked above1 the #ac per cent to #ae per cent nickel-iron alloys soften with quenching but not with annealing4 ,the #ae per cent nickel steel has the highest strength of the nickel-iron-carbon series4 ,though nickel and iron are each strongly magnetic1 alloys of the two which contain #bd per cent or more of nickel are not magnetic4 ,chrome and ,nickel-,chrome ,steels ,while 8simple0 chrome steel is pretty well known as a material for products which require great hardness1 such as balls1 roller bearings1 files1 rolls1 five-ply safes1 stamp shoes1 projectiles1 etc41 and heat-treated chrome-vanadium steels are now extensively used in forged frames and shafts of automobile and other machines1 a combination of nickel and chromium gives steels which have been great favorites4 ,with #b to #c per cent of nickel1 not over #c per cent of chromium and per cent of carbon1 these steels1 when expertly heat-treated1 can give 8elastic limits0 anywhere between #dj1jjj and #bej1jjj pounds per square inch1 with good freedom from brittleness4 ,they are very largely used for automobile gears1 axles1 and other parts1 for armor plate1 for projectiles and for many other purposes4 ,these alloys are also used for castings4 ,chrome-,vanadium ,steels ,within a comparatively short time the chrome-vanadium steels have come to be very largely used1 often in place of the chrome and nickel-chrome steels4 ,as vanadium is a 8deoxidizer10 whereas nickel is not1 the chrome-vanadium steels show fewer imperfections than the nickel-chrome steels and they also roll1 forge and machine better4 ,they are used for automobile frames1 shafts1 for miscellaneous forged and rolled articles and for heat-treated armor plates4 ,of this comparatively new material about #ij1jjj tons were made during #aiac1 according to a recently issued bulletin of the ,department of the ,interior4 ,it is impossible1 of course1 to even begin to impart any adequate conception of the qualities and great importance of the alloy steels for purposes of construction4 ,as has been shown they are special steels for special purposes and their application is wide4 ,incorporation of the new element in the alloy imparts peculiar and valuable properties3 for example1 #ab per cent of manganese1 great hardness and toughness2 #bc per cent of nickel1 non-corrosive properties and great strength2 chromium1 nickel with chromium or chromium with vanadium1 strength and high elastic limit 7resistance to distortion7 as well as great hardening power when desired1 this1 of course1 the usual hardening through quenching from a cherry-red heat4 ,very often instead of the single defining element1 a combination of two1 three or even four of them is used4 ,such1 of course1 are rather complicated steels having combinations of properties as might naturally be expected1 though very often these resulting properties are not those which are expected4 ,in fact no one can tell in advance what properties any new combination of metals in an alloy will produce and often new proportions of the same constituent metals give entirely different and unique results4 ,the only certain method of ascertaining what characteristics and properties a new alloy will have is to develop it and in that way find out4 ,description of a special and extremely important class of these alloys1 the 8high-speed steels10 will serve to show how laborious1 slow and expensive a process development of new alloys may be and what unlooked-for results are sometimes obtained4 ,,chapter ,,xv ,,the ,,high-,,speed ,,steels ,during early centuries the art of metal cutting made little progress except in-so-far as the application of greater driving power and the use of better machines were concerned4 ,lathes had been known since the sixth century ,b4 ,c41 at least1 but1 of course1 little was or could be accomplished1 comparatively speaking1 before the invention of the steam engine by ,watt1 which was the first contrivance to give sufficient power for machining purposes4 ,during the century which followed ,huntsman's time1 steel makers and smiths became very expert in the manufacture and tempering of carbon steels4 ,lathe tools were made of these carbon steels1 the only available material1 but even with the better machine shop practice of the #aith century they were capable only of what we now consider to be inefficient results4 ,the trouble was that since carbon tool steel gets its hardness from quenching from a red heat and then 8drawing0 the temper by reheating and slowly cooling from #djj or #ejj ,f41 tools made from it could not retain their hardness if their cutting points became much heated1 as occurred if the lathe was run too fast4 ,the usual cutting speed1 therefore1 was #bj or #cj linear feet per minute4 ,speeds in excess of this took the temper out of the tools and soon made them useless4 ,about #ahfh ,robert ,f4 ,mushet1 a metallurgist of ,sheffield1 ,england1 made a momentous discovery4 ,he found that a piece of tool steel which had cooled in the air was as hard as some of those which he had quenched4 ,being an investigator he set about discovering the reason for this experience which was without precedent4 ,analysis showed that beside the usual constituents of tool steel this particular bar contained tungsten1 a comparatively new metal4 ,he experimented with some hundreds of mixtures and evolved an alloy1 which1 in tools1 would stand up under machine speeds double those which could be used with carbon steels4 ,these new alloys became known as 8air-hardening0 or self-hardening tool steels because they required no quenching4 ,the principal application of these new steels was in the cutting of harder metal than it had before been possible to cut1 and little attention1 apparently1 was paid to the getting of greater outputs by increase of machine speeds4 ,at this point ,frederick ,w4 ,taylor of 8efficiency0 fame appears upon the scene4 ,while manager of the ,bethlehem ,steel ,works in the nineties of the last century1 he was working upon the efficiency investigations for which he later became so famous4 ,during his investigations1 with ,maunsel ,white he experimented with many air-hardening steels to determine the best grades to use for their shop work4 ,getting some inconsistent results they determined upon and made what was a most extended and systematic investigation1 one so thorough and complete that ,taylor and ,white have become part of the history of high-speed steels4 ,they produced new compositions the quenching of which could be from temperatures greatly in excess of those which tool makers for centuries had held to be ruinous and which really are ruinous to carbon tool steels4 ,the best results were obtained when the new steels were quenched by plunging in oil from close to their melting points--a dripping or 8sweating0 heat as it is called4 ,this was something entirely new but it developed that after proper drawing1 steels quenched from these extreme temperatures1 would stand up under lathe speeds as great as #bjj or #cjj feet per minute4 ,compare these with the miserable speeds of #bj or #cj feet per minute1 which were the average performances of the best carbon steels4 ,the secret of ,taylor and ,white's treatment was not long in coming out and soon high-speed steel makers in ,europe and ,america were vying with each other in production of finer and finer high-speed steels4 ,the progress which has been made during the last twenty years and particularly during the past ten has been astounding4 ,improvement has followed improvement in composition1 manufacture and heat treatment1 so that to-day1 instead of the cut at #cj feet per minute1 which was a high figure with carbon steel tools1 the modern lathe or shaper tool often works at #cjj or #djj or more feet per minute1 and1 with sufficient power behind it1 at somewhat lower speeds plows out inch deep and inch wide chips so fast that their removal to keep the machine clear is no mean problem4 ,often #b1jjj pounds of the material per hour can be thus cut away with one tool4 ,as suggested1 the new steels do not suffer such loss of temper from the heat generated by the friction of the tool in the metal as occurs with carbon steel tools4 ,in fact1 tools of high-speed steel work best after 8warming up0 and they can run for a considerable period of time with the point of the tool red-hot1 though such is not advisable4 ,as is readily seen the essential property of the high-speed steels is the so-called 8red hardness0 which is the ability to retain hardness at red heat4 ,this is several hundred degrees in excess of the temperatures at which the carbon tool steels quickly lose their 8temper40 ,as forecast by ,mushet1 the essential constituent of the new steels is the metal1 tungsten4 ,but tungsten alone cannot give the desired property4 ,mushet1 it will be remembered1 was the metallurgist whose patents for the use of manganese in steel ,bessemer was obliged to recognize to make his process a success1 though the metal had earlier been used in crucible steel4 ,the air-hardening property of ,mushet's steel was contributed by a happenstance combination of tungsten and this same metal1 manganese4 ,it later developed that tungsten and chromium were the best hardening elements and these have maintained their place1 though refinements of the past few years have made use of vanadium1 and1 more recently1 cobalt in addition4 ,usual amounts may be said to be tungsten #ad to #be per cent1 chromium #b to #g per cent1 with vanadium to #a per cent1 and cobalt up to #d per cent1 perhaps4 ,the carbon content is usually 4#f to 4#h per cent4 ,sometimes another comparatively rare metal1 molybdenum1 is used in high-speed steels in place of part of the tungsten1 but its use does not seem to be on the increase4 ,manufacturers differ considerably in formulas4 ,it will be noticed that at best there is left room for only #gj or #hj per cent of iron in the alloy4 ,from certain standpoints1 the high-speed steels might not at first thought be called 8steels0 at all since carbon seems to be of so little importance4 ,they might be considered to be low carbon alloys somewhat similar to the newer 8stellite0 7an alloy from which tools are made71 which contains little or no carbon and no iron but is made up mainly of cobalt and chromium4 ,they fit in1 however1 with the general and very comprehensive scheme of classification of the iron-carbon alloys which has been developing over a period of twenty years and there is no doubt among metallurgists and metallographists that1 as is the case with the alloy steels described above1 they are iron-carbon alloys--in other words1 steels--the properties of which have been greatly modified through the presence of the other elements4 ,carbon1 therefore1 is an essential1 though it is much less in amount than in the carbon tool steels4 ,the hardening and softening properties1 also1 very definitely classify these alloys with the 8tool steels40 ,stellite cannot be softened4 ,as with the carbon tool steels1 most of the high-speed steels are made by the crucible method1 though a small but increasing amount is of late being produced in the electric furnace4 ,after careful pouring into small ingots and cooling1 the ingots are removed from the iron molds and 8topped0 to remove any 8pipe0 or unsound portion4 ,then1 if without defect and satisfactory as to analysis1 they are slowly and carefully heated to forging temperature and are hammered out into bars4 ,by this method they are taken nearly down to the final size desired4 ,the bars are finished by rolling to size4 ,after careful annealing they are ready for shipment to the tool maker4 ,when taking heavy cuts a tool of to-day may exert as much as ten tons' pressure against the metal it is cutting and the advent of this wonderful material for tools necessitated the building of immensely heavier and stronger lathes and other machines1 which1 alone1 were capable of giving them power to do their work4 ,the high-speed steels1 therefore1 have revolutionized metal-cutting practice and shop methods and have very largely aided efficiency4 ,,chapter ,,xvi ,,the ,,mechanical ,,treatment ,,of ,,steel ,molten steel is practically always poured into upright molds of cast iron which shape it into long slightly tapering blocks of metal of square or rectangular cross-section4 ,after the ingot mold has been stripped off1 the still red-hot ingot cannot well be taken directly to the rolls1 for1 while the exterior parts may have the proper temperature for rolling1 the interior of the ingot may still be liquid4 ,the ingot1 throughout1 should be uniform in temperature when it is rolled4 ,it is therefore put into a closed pit or furnace of proper temperature where the center of the ingot can be cooling while the outer portions are kept hot or are reheated if necessary1 until all is ready for the rolling operation4 ,it would take a 8steel man0 a long time to tell you all of the unfortunate things that can and do happen to such blocks or ingots of steel which influence their applicability to the purposes for which they are intended4 ,you must have learned of the most serious of these--8pipes10 8cracks10 8segregation10 etc41 through reports of investigations of broken railroad rails and accidents caused thereby4 ,a word or two regarding these3 ,in the ingot mold the outside of the steel ingot is1 of course1 the first to solidify4 ,it may be hours after the freezing of the outer crust before the interior is able to cool sufficiently that it1 too1 can set4 ,as steel1 like most other metals and alloys1 occupies less space when 8frozen0 than it does when molten1 there must occur a hollow space in the interior since the crust is solid and cannot contract much4 ,this hollow space usually takes the form of a more or less elongated cavity extending along the axis of the upper quarter of the ingot4 ,it is called a 8pipe40 ,illustration3 ,,pipe ,,and ,,blowholes ,,in ,,an ,,ingot ,,of ,,steel ,then1 too1 the metalloids of the steel do not always stay where they belong4 ,even if the steel has been of a uniform chemical composition when poured1 the interior portions of the ingot after cooling will be found to have a greater amount of sulphur1 phosphorus and carbon than parts which are nearer the surface4 ,such gathering together of constituents of the steel is known as 8segregation40 ,with the development of the steel industry and the demand for greater and greater tonnages1 ingots have been made larger and larger4 ,piping1 segregation1 etc41 are very naturally accentuated in the large masses of steel4 ,much 8gray matter0 has been expended in attempting to overcome these and other defects to which large steel ingots are liable4 ,covering the molten ingot top with charcoal2 filling in before complete solidification with additional molten metal2 and keeping the ingot top molten by application of powerful gas flames have been1 perhaps1 the most useful methods4 ,but1 even so1 piping and segregation have not been completely prevented1 though great improvement has resulted4 ,the usual way around the difficulty is to make certain that only the bottom 7or best half7 of each ingot is used for the most important products1 such as locomotive and car axles1 firebox and boiler plates1 rails1 etc4 ,the next or third quarter or a little more is utilized for products which go into less exacting service4 ,these may be plates for ordinary water tanks1 for flooring1 for ship plates1 etc4 ,the top part which contains the pipe is cut off and goes back to the furnace to be remelted4 ,it is termed 8discard40 ,the big steel makers themselves shape most of their steel into such finished products as rails1 plates1 rods1 and wire4 ,some of it is by them reduced from the ingot into intermediate 8blooms10 8billets10 8bars10 etc41 and sold in this form for the manufacture of axles1 drop forgings and the hundreds of products which we each day see4 ,it is a very fortunate circumstance that at a cherry-red or white heat the carbonless irons and most of the steels can be quite easily fashioned into products4 ,as is well known to us the most usual methods of mechanically shaping these metals while hot are by hammering1 by rolling and by forging in a press4 ,with sufficient power and proper appliances1 soft and medium steel to a considerable extent can be fashioned cold1 but1 of course1 in this condition its resistance to reshaping is immensely greater4 ,the cold treatment of these metals is usually some form of tube or wire drawing4 ,certain other methods such as extrusion1 spinning1 etc41 are also in use1 and1 through them1 some otherwise difficultly formed products are made4 ,in one of the earlier chapters we saw that annealing refines 7make finer7 the grain of a steel casting and improves its physical properties4 ,annealing for refining purposes is practiced with other steel products also1 and with just as effective results4 ,however1 the mechanical shaping of steel while at cherry-red or at a white heat much more materially refines the grain while helping the strength and greatly increasing the ductility of the alloy4 ,steel which has been hot-forged or rolled is said to have been 8hot worked40 ,steel usually is 8hot worked10 for 8cold-working0 methods are not so generally applicable and the product is more liable to suffer under the more drastic treatment4 ,the amount of 8hot-work10 at proper temperatures1 that low and medium carbon steels will stand with improvement of the grain and physical properties is considerable4 ,as we must anyway shape the metal into useful implements and other products1 it is fortunate that the quality of the metal is benefited by the process4 ,illustration3 ,no4 #fi;a4 ,,photomicrograph ,,of ,,cold-,,drawn ,,steel ,,wire ,,showing ,,distortion ,,of ,,the ,,crystals ,,from ,,cold ,,working ,hot ,working does not produce distortion but makes the grain finer4 ,annealing relieves this distortion to a great extent4 7,magnification #gj ,diameters47 ,forging ,illustration3 ,man ,undoubtedly the earliest shaping of ferrous 7iron7 metals was by hammering the small balls of metal into bars1 spears or swords4 ,presumably it was done with stone hammers which later had to give way to hammers made of iron4 ,these had sufficient hardness to serve the purpose well4 ,for hundreds of centuries the shaping of iron1 steel and the other metals into tools and weapons must have been done by such forging methods4 ,it is not difficult for us to picture the early smiths at their work1 laboriously and yet very skillfully hammering into spear-heads and sword-blades the lumps of iron or ,wootz ,steel which they had made in their crude furnaces4 ,illustration3 ,,the ,,old ,,oliver ,,foot-,,power ,,hammer ,illustration3 ,,an ,,old ,,forge ,,hammer ,in much the same way1 though on a considerably larger scale and with heavier and better hammers and tools1 was the same work done up to the time of the invention of ,cort's rolling process--about #aghc4 ,various styles of hammers were used1 some with a spring pole attached to raise them for the next stroke which was delivered by foot power1 others known as 8helve0 or 8shingling0 hammers gave periodical blows as teeth on a revolving wheel lifted and allowed the hammer heads to fall4 ,the heavier ones often gave as many as seventy-five and the lighter ones which were used for 8tilting0 7forging7 shear steel into bars or implements as high as three hundred blows per minute4 ,illustration3 ,,the ,,squeezer ,,was ,,sometimes ,,used ,,in ,,place ,,of ,,the ,,hammer ,illustration3 ,,the ,,old ,,tilt ,,hammer ,though ,cort's rolls very materially aided in the shaping of balls of iron from the puddling furnace into bars1 the hammering or forging method remained the one by which finished iron and steel articles were made4 ,about #ahce it happened that a very large propeller shaft for a new ship was desired4 ,being so large1 no one was found who could forge it until the matter was put before an ,english iron-worker named ,james ,nasmyth1 who had a reputation for ingenuity4 ,nasmyth roughly sketched out an immense hammer which he proposed to operate by steam4 ,there was no opportunity to build it1 however1 for the propeller shaft never was ordered4 ,but the idea of the steam hammer got to certain ,french engineers1 who constructed one which ,nasmyth came upon during a visit to a ,french iron works4 ,nasmyth realized the importance of his invention1 which1 luckily1 the ,frenchmen had not attempted to patent4 ,a patent was granted to ,nasmyth4 ,illustration3 ,a ,,belt-,,driven ,,power ,,hammer ,,of ,,to-,,day ,to most of us the steam hammer1 still little changed in essentials1 is quite well known and some of us have witnessed the cracking of an egg without breaking the egg cup which held it4 ,the adjustment and regulation of these mammoth hammers is so nice that with almost successive blows a skillful operator can flatten a piece of iron and then break the crystal of a watch without otherwise injuring the timepiece4 ,needless to say1 the steam hammer has proved to be the only efficient hammering device for forging large pieces4 ,illustration3 ,,two ,,board ,,hammers ,,and ,,trimming ,,press ,but whether made in the small way of the village blacksmith1 by the larger helve1 tilt1 ,bradley1 or by the monster steam hammer1 each forging1 unless made in a die1 must be considered to be specially formed and no two pieces1 when finished1 are exactly alike4 ,they are always 8hand made0 articles4 ,drop ,forgings ,many years ago1 what are known as duplicate or interchangeable parts1 therefore1 were quite unknown and it is related that parts of the famous ,english ,enfield rifle were made in various parts of the civilized world1 shipped to the ,tower of ,london and there assembled4 ,but during assembly1 the various pieces had to be filed and carefully adjusted by hand because no two parts were exactly alike4 ,but the 8,yankee tool makers0 of ,new ,england solved the problem by forging the pieces of which many duplicates were necessary in a 8die0 or impression in a block of steel4 ,the forged pieces1 of course1 took the exact impression of the 8die0 and successive pieces thus made were alike in size and shape4 ,from finished duplicate parts which went to ,london from the ,new ,england states1 the ,enfield rifle was assembled with very little final finishing of the 8cut and try0 variety4 ,done at first with the die on a blacksmith's anvil and with a light hammer1 this promising method soon developed expert 8die-sinkers0 7die makers71 also ingenious men of whom the term 8,yankee ,tool ,makers0 is self-explanatory4 ,in connection with this work what are known as 8drop hammers0 came to be largely used4 ,of these an important type were the 8board hammers10 in which the heavy steel hammer-head was attached at the bottom end of a vertical board set between pulleys4 ,as the pulleys squeezed and revolved against the board it was carried up between them and dropped1 when the pulleys loosened it at whatever height was desired4 ,rapidly and periodically ascending and dropping upon the anvil beneath1 it quickly forced the white-hot iron into the 8die0 upon the anvil1 forming what have since been known as 8drop forgings40 ,illustration3 ,,nasmyth',s ,,steam ,,hammer ,,revolutionized ,,steel ,,working ,commonly the hammer face itself carries the impression of the upper part of the article to be formed1 i4e41 there is an upper 8die0 on the hammer and a lower one on the anvil4 ,illustration3 ,,modern ,,forging ,,of ,,an ,,automobile ,,crank ,,shaft 8,fins0 were of course1 left all around where the excess metal was squeezed out from between the upper and lower dies4 ,it shortly developed that a second pair of dies shaped for trimming could clean the forging of this excess metal1 which is so well known under the appellation1 8flash40 ,nasmyth's steam hammer1 also1 has been used very largely for drop-forging work4 ,a 8cast0 metal is not and cannot be as dense1 free from holes1 sponginess or other defects or as strong as 8worked0 metal4 ,while often not as cheap as castings as far as cost of production goes1 8drop forgings0 are usually considerably superior to them and are to be preferred4 ,however1 it does not pay to make dies unless for many pieces4 ,one or several 8castings0 can be made without great expense4 ,forging of ,large ,pieces by ,hydraulic ,press ,of late years much forging has been done1 not by the hammer which gives such a sudden1 superficial blow with shallow working of the piece1 but by hydraulic or other press1 which very slowly squeezes the hot piece to smaller and longer shape4 ,sir ,henry ,bessemer was one of the first to realize the advantages of and make use of the press for steel working4 ,unlike the hammer the press exerts a deep working of the piece which can be seen to flow throughout under the stress rather than in surface only as occurs under the hammer4 ,this is very desirable as the interior1 which is known to have much coarser grain than outer parts1 particularly needs to be 8worked40 ,in plainer terms the press seems to knead the mass much as the bread-maker kneads dough1 while the hammering method simply batters down the outside4 ,at a glance an experienced eye can tell from the appearance of the end of a forging whether it has been pressed or hammered4 ,illustration3 ,a ,,modern ,,hydraulic ,,forging ,,press ,pressures as high as #h1jjj pounds per square inch are used in hydraulic presses1 though much lower pressures are more common4 ,forging vs4 ,rolling ,though we have not yet considered the rolling mill or its products1 we understand that1 in general1 only products of regular and uniform cross-section and of considerable length can conveniently be rolled4 ,where they can be obtained of satisfactory shape and size1 steel products formed by the rolling process are highly desirable and are usually cheaper than those which are produced by the forging process4 ,compared with those made by the rolling process1 forged products are usually quite costly in labor and time4 ,rolling mills1 however1 cost immensely more to build and equip than do plants installing even the steam hammering outfit1 so the rolling process cannot pay except for such articles as are demanded in great quantities4 ,articles of irregular and odd shape must1 of course1 be forged and here1 especially for very small articles1 the drop-forging process is available and highly satisfactory where enough pieces of one kind and size are wanted to pay for the requisite dies4 ,forged articles have another advantage which we should not overlook4 ,the physical properties which are imparted during forging are somewhat superior to those which the rolls bestow4 ,the physical properties shown by the latter are very satisfactory1 however4 ,,chapter ,,xvii ,,the ,,rolling ,,process ,illustration3 ,,early ,,rolls ,after invention of the puddling furnace with its rather large yield from the standpoint of those days1 ,cort about #aghc found the hammering method unsatisfactory for his purposes and rolls were devised by him to facilitate working of the larger balls of iron which his furnace produced4 ,his rolls were provided with a series of grooves which systematically reduced the balls of iron to pieces of longer and longer length and proportionally decreasing diameters4 ,they were power driven and served very well as long as iron and steel were made in quantities no larger than those which were produced in the puddling and crucible furnaces4 ,quite naturally there was little or no change in the essentials of rolling mill design until it was forced by the invention of the ,bessemer steel-making process4 ,with that occurrence trouble began4 ,the open-hearth process followed1 and1 with the increasingly large steel outputs of mills using these processes1 necessity after necessity developed which resulted in the highly developed rolling mills of to-day4 ,illustration3 ,mill ,the 8,two-,high0 ,mill ,the mill as invented by ,cort had but two rolls and these were actuated by a fly wheel4 ,turning in one direction continually1 the rolls allowed the piece being rolled to go through in only one direction1 i4e41 it had to be returned from the rear to the front side of the mill after every passage1 usually called 8pass40 ,this was done by the 8catcher10 a brawny man at the rear of the mill1 seizing the piece1 lifting one end bodily to the top of the upper roll over which it was carried back with more or less difficulty and awkwardness to the 8roller10 who1 from the front1 seized and entered it again into the next succeeding or smaller groove of the rolls4 ,illustration3 ,,two-,,high ,,rolls ,,and ,,effect ,,on ,,the ,,piece ,the 8,three-,high0 ,mill ,illustration3 ,,action ,,of ,,three-,,high ,,rolls ,in #aheg ,john ,fritz was watching his men at their slow and fatiguing work at the two-high mill of the ,cambria 7,pa47 ,iron ,works4 ,the thought struck him that by adding another or third roll at the top1 the piece could also be given a pass on every trip back to the roller in front4 ,the rolls would of course pull it through1 the work would be less severe on the men1 and1 receiving passes in both directions1 the piece would receive the full number in approximately one-half of the time which was then required1 and1 more important than all else1 it would not have nearly so long a time to cool and could be finished at a more desirable temperature--a great advantage4 ,strange to say the idea was immediately pronounced impracticable when he mentioned it and it was necessary for him to go through a long fight to obtain permission to make a trial4 ,the experiment was from the first successful but the mill burned one ,saturday night1 having supposedly been set afire by workmen who feared loss of their jobs4 ,rebuilt and manned by new workmen it ran with success4 ,the succeeding ten years saw the 8three-high0 type of mill come into extensive use both in ,america and ,europe4 ,elevating or tilting tables have since been provided which mechanically raise the piece to the upper rolls1 thereby relieving the workmen of this duty1 which1 with the great increase in size of ingots and pieces rolled soon became very arduous4 ,to-day the 8three-high0 mill is just as important as ever4 ,the ,reversing ,mill ,having a fly wheel for the storing-up of power1 the rolls must keep turning continuously in the established direction4 ,in ,england1 ,nasmyth--the same man who invented the steam hammer--suggested that the fly wheel be dispensed with and the two-high rolls reversed after each pass4 ,the piece would go back to the roller's side receiving work in a regular pass on the way1 just as in the three-high return4 ,the idea was developed by ,mr4 ,ramsbottom of the ,london and ,northwestern ,railway ,company4 ,by the use of powerful enough engines the desired end was accomplished and this type is now quite generally used for very heavy ingots which it is not economical to lift by tilting tables in the three-high mill process4 ,there are certain other advantages also4 ,the above are the three general types of mills4 8,breaking-,down0 the ,ingot ,whether it is to be sold in intermediate shapes or further rolled down into a finished product1 all ingots have to be 8cogged0 or broken down into intermediate-sized slabs1 blooms or billets1 for an ingot contains altogether too much steel for any single plate1 rail1 rod1 or other finished product4 ,the cogging or first rolling is accomplished in one of the three types of rolls already described but now more generally in the reversing mill4 ,illustration3 ,,ingot ,,coming ,,out ,,of ,,the 8,,soaking ,,pit0 ,when the tongs of the big overhead crane have lifted the white-hot ingot out of the soaking pit it is run back and forth through the rolls which are forced nearer and nearer together by the 8screw-down0 man so that the piece continually becomes thinner and much longer with each pass4 ,tables made up of small rollers geared together receive the long piece as it emerges from the rolls4 ,after each pass they bring the piece back to the rolls which are now turning in the opposite direction4 ,the table on the other side repeats the process1 the piece being regularly turned on edge or slid from one side of the rolls to the other by steel guides which can be raised up between the rollers of the tables where desired4 ,the direction of these as well as of the rolls themselves is controlled through levers by two or three men standing at one side of the mill4 ,reversing after each pass1 with the big ingot apparently turning and sliding itself into the most advantageous position for the next entry1 the big engine1 mill and roll-train seem almost human4 ,illustration3 ,,ingot ,,in ,,the ,,rolls ,the ,rolling of ,steel ,plates ,it is manifestly impossible in the space at disposal to give in much detail the rolling of many of the better known products4 ,fortunately it is not necessary1 for after description of the making of plate1 pipe and tube1 and of rod and wire1 the rolling of other forms such as rails1 bars1 and the structural shapes1 ,i beams1 channels1 angles1 ,z bars1 etc41 can well be imagined4 ,illustration3 ,,steel ,,billets ,,for ,,forging ,,or ,,other ,,purposes ,from the contract department to the mill clerk come the orders for plate1 with detailed list of sizes and thicknesses1 and definite specifications of quality in terms of chemical and physical requirements1 etc4 ,illustration3 ,,rolling ,,ingot ,,into ,,slabs ,after studying these1 the clerk makes requisition upon the open-hearth furnace for such tonnages of steel of various compositions as he estimates will give him sufficient stock for his purposes4 ,as soon as possible the steel is made and poured into ingots which are transferred to the soaking pits of the slabbing mill there to await disposition as soon as the chemical laboratory has made analysis of the sample taken and has reported by telephone the result to the clerk who ordered the material4 ,if close enough to the composition he ordered1 he sends to the slabbing mill his requisition ordering them to roll and cut the four or six ingots of the 8heat0 into slabs of definite weights1 each one designed for a plate on a customer's order4 ,the clerk at the slabbing mill determines to what width and thickness each ingot shall be rolled and in what varying lengths it is to be cut to furnish slabs of the definite weights ordered in the requisition4 ,after rolling the ingot down to proper width and thickness1 the 8piped0 end is cut off and 8discarded40 ,slabs are cut and piled in regular order on a little flat steel car on which they are pulled1 still red-hot1 by the shrieking little dummy engine out from the slabbing mill1 through the yard and to the plate mill furnaces1 into which they are charged in proper order4 ,here they remain until they are again white-hot and the plate mill roller is ready for them4 ,meanwhile record sheets giving the heat number1 the number of the ingot and the weights of the slabs in the order in which they were piled come to the plate mill clerk4 ,from these and the results of analysis of the steel he makes out the rolling orders for the plates to be manufactured4 ,illustration3 ,,slabs ,,from ,,which ,,plates ,,are ,,rolled ,you have heard how difficult it is to get solid ingots and how the top eighth 7or sometimes more7 of an ingot is usually 8piped0 and discarded4 ,now slabs from the balance of the ingot were piled on the car and have been charged in the plate mill furnace4 ,those from the upper part of the ingot 7next to the discarded part7 are used for the less exacting qualities of plate4 ,only the bottom half of the ingot1 which of course is the solidest and best1 goes into the higher grades of plate1 such as 8fire box10 the choicest grades of 8flange0 steel1 etc4 ,the third quarter goes into flange stock1 8ship0 and 8tank0 plate1 the latter representing miscellaneous lower-priced plate which may be used for water tanks1 steel flooring1 etc4 ,steel known as 8fire box0 of course must be of very high grade4 ,it is used for parts of locomotives1 etc41 which come in contact with and likely will suffer deterioration from flame1 smoke1 etc4 ,the best 8flange0 goes into boiler plates and other products which have to stand considerable bending to shape4 ,in making out his rolling orders the clerk sees that each numbered slab is ordered rolled only into a product for which it is well suited4 ,he has to take into consideration the chemical composition1 the probable strength and other physical properties which were definitely named in the specifications of the customer's order4 ,and1 as the physical properties of such steel are mightily affected by temperature and speed of rolling and by rapidity of cooling1 he must know mill practice and constantly keep in touch with the results which the physical testing laboratory is getting from bars sheared from such of his plates as have been 8pulled0 for customers or the inspectors who represent them4 ,when hot1 the slabs one by one and in regular order come to the rolls from the furnace4 ,following his rolling orders the roller and his helpers put each slab back and forth through the plate mill rolls1 first drawing it out to a width a few inches greater than the plate to be sheared from it1 and then turning it a quarter around1 they draw it out in the rolls until it has come down to the proper thickness or 8gauge40 ,if the clerk's computations have been correct the plate will now have the proper length4 ,however1 he may have ordered a slab of insufficient weight to make it1 particularly if the rolls have become much worn4 ,it will hardly be realized how much the width and thickness of the plate ordered have to do with the 8percentage0 of trimmed plate which the mill will get out of the slab ordered4 ,there is a 8fish tail0 on each end of a rolled plate4 ,on a thin1 wide plate this becomes rather serious4 ,wherever possible the clerk puts two or three plates end to end and perhaps narrow ones side by side1 but he must not exceed the width which the 8shears0 can 8split0 nor give the mill such a long plate that it will become too cold to roll or too long to be conveniently handled4 ,illustration3 ,,an #hd-;,,inch ,,plate ,,mill ,for diversion the mill men take delight in throwing an extra amount of salt upon the plate to rid it of scale when nervous visitors have come as close to the rolls as their conductor through the mill will bring them4 ,the explosion which comes from the usual amounts is much intensified and it is not at all out of the ordinary to hear shrieks from the women and to see surprised and somewhat dismayed men among the visitors4 ,plate mills are usually three-high with tables of small rollers on each side which tilt to feed the plate into the rolls and to receive it on the other side from which it is fed in again1 either above or below as the case may be4 ,as the plates must be flat1 perfectly plain rolls are used4 ,for plates which are very wide these rolls may be #adj inches or more long and perhaps three feet in diameter4 ,the rolls1 of course1 are kept flooded with water to keep them cool4 ,at first thought one would think that the water would cool the plates which are being rolled4 ,it does not materially do so1 however1 the extreme heat apparently keeping the water from coming in actual contact with them4 ,thus they are rolled down from the three-inch thick slab to 1 or 1 and from #f1 #h1 #aj1 or #ab slabs into 1 or possibly #a or #a plates4 ,illustration3 ,,the ,,rolling ,,of ,,plates ,all plates must be rolled very accurately to gauge1 allowance of variation often being not over one or two hundredths of an inch4 ,the roller must be a man of experience and of very good judgment for slabs for almost any plate may come of any one of several thicknesses and lengths4 ,he must know his temperatures1 speeds of rolling and the amount of reduction given with each pass1 and1 particularly in case of thin1 wide plates1 the condition of his rolls1 which after two or three days' wear will produce plates thicker in the middle than at the edges4 ,as the 8screw-down0 man on top screws the rolls together a little with each successive pass and the 8hookers0 under the roller's direction keep the plate entering the rolls properly1 he must with his very accurate gauge measure the thickness of the plate as it nears completion4 ,especially when plates are ordered and paid for by average weight per square foot must he judge accurately the thickness of the center of the plate where he cannot measure1 and pull down the edges enough that the finished plate when sheared will average right4 ,it is fortunate for the steel mill men of this country which does not know the advantages of the metric system that a steel plate one inch thick weighs very close to #dj4h pounds per square foot4 ,this is an easy figure and the clerk1 roller1 hot bed foreman1 weighers and all concerned 8think0 in terms of a plate one foot square and one inch thick4 ,one-half inch plate1 therefore1 weighs #bj4d lbs42 1 #aj4b lbs42 and 1 #g4ff lbs4 per square foot4 ,as will be seen when we consider wire drawing and cold-drawn seamless tubes1 the strength and other physical properties of steel depend first1 upon composition1 and1 secondly1 upon temperature at which they are hammered1 rolled1 or otherwise 8worked40 ,therefore1 plates can be much modified in physical properties by finishing at chosen temperatures4 ,a steel containing 4#ai of carbon and 4#de of manganese1 for instance1 which in one inch plate should give a tensile strength of around #ee1jjj pounds per square inch1 #eh1jjj pounds in or #fb1jjj pounds in when finished at usual temperatures1 by slightly 8colder rolling0 can be made to show a considerably greater strength4 ,of course1 the ductility is somewhat reduced1 but1 with a moderate amount of cold rolling1 it will not be enough to do harm4 ,all of these and many other details must be not only kept in mind but become second nature to the plate worker4 ,after the final pass the plates go upon the 8hot bed0 where they are laid out side by side in the order in which they have been rolled4 ,they must now have marked out upon them the boundaries of the smaller plates or pieces into which they are to be cut4 ,from a duplicate of the roller's sheet the hot bed foreman marks upon the end of each plate what is to be laid out and boys or men wearing shoes with thick soles of old belting or other cheap non-conducting material go upon them with chalk and 8squares0 which are somewhat similar to the carpenter's square but having 8legs0 six and twelve or fifteen feet long4 ,though the soles of their shoes smoke from contact with the still hot plate1 they very quickly and accurately mark out upon its surface the design which the hot bed foreman has signified4 ,usually the plates laid out are rectangular and of standard size but often the boys have to lay out pieces of odd sizes and shapes1 and sometimes1 what are known as 8sketches0 have to be drawn using arcs1 chords1 radii1 etc41 as the student in geometry draws his geometrical figures4 ,round plates for boiler heads1 tank ends1 etc41 in plate mill parlance are termed 8heads40 ,these are marked out with string and a piece of chalk4 ,a boy with a pot of white paint follows and paints on the surface of each piece laid out its size1 thickness1 the customer's name1 the order number and heat number4 ,that the plate can always be identified1 even after exposure to severe service or weather conditions1 another boy with steel stamps follows and stamps into the steel the heat number4 ,cranes with magnets or hooks convey the long plates to the 8goose necks0 over the small rollers of which they are pulled to the shears where the powerful steam or hydraulically-operated square-edged knife with ease trims the ends and irregular edges along the chalk lines into the sizes marked4 ,accuracy is everywhere necessary as over or under ordered dimensions or a variation of two hundredths of an inch in thickness may and probably will cause rejection of a plate4 ,after weighing and recording1 the plates are conveyed to the shipping yard1 where they are loaded by electro-magnets into cars for shipping4 ,in the plate mill process above described plates anywhere between #cj and #abj inches in width1 say1 can be rolled4 ,and as mentioned1 the more or less irregular edges on the sides are 8sheared0 off4 ,this extra allowance1 which must be given1 of course becomes 8scrap40 ,for plates which can best be rolled in long narrow lengths a 8universal0 plate mill is often used4 ,this has vertical rolls just back of the two horizontal rolls1 which are adjustable so that the plate can be regulated1 not only as to thickness1 but also as to width as well4 ,such mills give plates which have to be trimmed on the ends only1 the sides being quite smooth4 ,illustration3 ,,loading ,,plate ,,from ,,the ,,shipping ,,yard ,the rolling of plate has been described thus in detail that a slight conception can be obtained of the refinement and the minutia which is a necessary part of modern mill practice4 ,american outputs which have grown to as much as several hundred tons per twelve-hour turn1 require that every operation move along with 8clock-like0 precision4 ,but with this immense tonnage and with all of the handicaps of occasional broken rolls and machine parts1 electric crane delays1 and illness of important men1 the work must be and usually is kept up without serious delay4 ,modern metallurgical and rolling mill practice is a marvel4 ,sheets ,illustration3 ,,the ,,rolling ,,of ,,sheets ,most plates are rolled from slabs which are about #cf inches wide1 but 8sheets10 which are plates less than thick are rolled from much smaller-sized slabs known as 8sheet bars40 ,after 8pulling out0 into sheets these may be folded once or even more times1 so that from two to eight thinner sheets are rolled at once4 ,that they may not weld or stick together under the heavy pressure1 they must be rolled colder than are single plates4 ,they are later trimmed and pulled apart4 ,some mills start sheet bars of smaller size1 for each sheet a separate piece1 which1 after drawing out somewhat are piled1 two1 three1 four or five high4 ,with coal or charcoal dust--either dry or mixed with water--between them1 they are heated and rolled1 the charcoal and coal dust keeping them from sticking together4 ,after annealing1 pickling1 etc41 they may be cold finished in polished rolls or otherwise treated according to the purpose for which they are intended4 ,after straightening some are galvanized1 others are tinned1 blued or painted4 ,most of them are sold 8black10 i4e41 with no coating at all4 ,terneplate has a coating of #ge of lead and #be of tin4 ,the ,rolling of ,rails and ,structural ,shapes ,it will be readily understood after reading the above1 that1 instead of using plain rolls1 mills for rolling steel rails1 ,i beams1 channels1 angles1 ,z bars1 rods1 etc41 must have grooved rolls4 ,for these products the first pass will be through a groove slightly smaller than the bloom or billet4 ,successive passes will be through other grooves in the same set of rolls which will gradually make smaller and bring more nearly to the finished shape the piece being rolled4 ,illustration3 ,,rail ,,in ,,the ,,finishing ,,rolls ,before our eyes the white-hot bloom enters the three-high mill1 goes backward and forward through the rolls and very shortly assumes the general shape desired4 ,each pass thereafter brings it nearer to the finished shape4 ,rails1 for instance1 are rolled out from the blooms into one long rail perhaps #adj feet in length which glides along like a huge snake to the swiftly revolving 8hot0 saws which are so spaced that four #cc-;foot rails are sawed from it at the same time4 ,as the rails pass from the saws to the cooling bed they are marked by a revolving stamp4 ,when cool they go to the straightening yard1 are straightened1 drilled1 inspected and later loaded into cars for shipment4 ,the production of all kinds of finished rolled iron and steel products in the ,united ,states during the past twenty-eight years is given in the following table which shows how extensive are our rolling mill industries and the rapidity of their development4 ,year,iron and ,plates ,nail ,wire ,rods,structural,all ,other ,total ,steel and ,plate ,shapes ,finished ,gross ,tons ,rails ,sheets ,rolled ,prod4 #ahhgb1aci1fdj #fjc1ceecjh1dcb #b1ahd1bgi #e1bce1gjf #ahija1hhe1cjg #hji1ihabea1hbh #deg1jii #b1fah1ffj #f1jbb1hge #ahiea1cjf1ace #iia1dei #ie1jhe #gia1acj #eag1ibj #b1dhg1hde #f1ahi1egd #ahiib1bgb1gjja1ijc1eje #he1jaea1jcf1cih #hej1cgf #d1adf1dbeaj1bid1dai #aijab1hgd1fcib1bed1dbe #fh1heja1cfe1icd #a1jac1aej #d1ggb1cbiab1cdi1cbg #aijcb1iib1dggb1eii1ffe #fd1ajba1ejc1dee #a1jie1hac #d1ieb1aheac1bjg1fig #aijec1cge1ibic1ecb1bcj #fd1edba1hjh1fhh #a1ffj1eai #f1cih1ajgaf1hdj1jae #aijgc1fcc1fedd1bdh1hcb #eb1jbgb1jag1ehc #a1idj1ceb #g1igb1cgdai1hfd1hbb #aijic1jbc1hded1bcd1cdf #fc1gdfb1cce1fhe #b1bge1efb #g1gaa1ejfai1fdd1fij #aiaab1hbb1gijd1dhh1jdi #dh1ebbb1dej1dec #a1iab1cfg #g1caf1iijai1jci1aga #aiacc1ejb1ghje1gea1jcg #cg1ejcb1dfd1hjg #c1jjd1igbaj1jcj1addbd1gia1bdc #aiaeb1bjd1bjcf1jgg1fid #ca1ibic1jie1ijg #b1dcg1jjcaj1edf1ahhbd1cib1ibd ,specifications and ,inspection ,customers1 of course1 have a right to see that their specifications are lived up to4 ,though years ago the mills perhaps intentionally sold to customers products which did not fulfill his specifications to the letter1 it is not generally so to-day4 ,now the mills' own inspectors are commonly more severe in their rejections of products than are the representatives which the customers themselves send4 ,not only does the mill laboratory make careful and accurate analysis of each heat or batch of steel made1 but1 after its application to orders1 pieces of plate1 shapes or rails rolled from it are examined1 gauged1 and test bars of the steel are pulled in the physical testing laboratory4 ,the mill rightly recognizes that it is for its own interest that the standard of its product be kept high4 ,a trip through one of the large steel plants with its furnaces1 its blooming and slabbing mills1 its rail1 plate1 structural and rod mills is one of the most interesting that can be taken4 ,if the visitor is not afraid of smoke or dust or of what seems to him an uncomfortable heat on a warm day he will discover new worlds4 ,no particular attention is paid to the casual visitor to the plant1 but1 for those who show real interest1 steel men have a warm welcome1 from manager to the sample boys4 ,,chapter ,,xviii ,,the ,,rolling ,,of ,,rods ,steel rods and what we will call large wires are rolled from billets which are long1 and approximately square blocks of steel4 ,the size and shape of the billets used vary1 depending upon the process and the size of the rod to be rolled4 ,much of the finished rod is sold as such for various purposes for which round steel is desired and an immense tonnage of one of the smaller sizes is used as the intermediate raw material from which wire is drawn4 ,rod mills have a very interesting history1 which1 by the way1 is but one of several histories of the development of the iron and steel processes and products which should make us proud of the genius of man in the way of metallurgical1 mechanical and business development4 ,the ,belgian ,mill ,the first bars and rods were rolled in the old two-high mill1 where1 after each pass they were pulled back over the top roll and inserted into the next groove by the roller as is usual with the two-high mill4 ,then along came the three-high mill which probably resulted in greater advantage to rod rolling than to other lines1 important1 even1 as it was to them4 ,but long1 thin bars or rods are quite pliable when at white or rolling heat and the 8catcher0 soon discovered a way by which he could save time and push up his tonnage4 ,he skillfully caught the forward end of the bar as it came through1 and1 giving it a quarter twist1 he inserted it in the proper return groove without waiting for the whole bar to run through to his side before starting it on its return journey4 ,this1 of course1 was easily possible with the slow speeds then used4 ,naturally the rod coming through from one side and going back to the other formed a loop4 ,the roller1 at the front1 was not slow in discovering that on long rods he could do the same thing1 so rods were soon regularly going through three or more passes at the same time4 ,illustration3 ,,wire ,,drawing ,,of #cej ,,years ,,ago ,it was soon found out that it was better to use a second set of rolls placed end to end with the first for the third and subsequent passes as the roller had hardly room or time to loop the rod on the return and start his next one4 ,this second set of rolls was connected on the same shaft and therefore made to run at the same speed as the first4 ,it worked out that by use of such extra sets of rolls and an additional helper or two the same long rods could be running through as many as six or seven passes at once with a great saving in time4 ,as it came from the final pass the forward end of the finished rod was seized in a pair of tongs by a boy who ran with it away from the rolls1 stretching it out along the floor to cool4 ,as the various sets of rolls were connected on the same driving shaft and revolved at the same speed1 the loops which were formed between passes continually grew longer4 ,here1 too1 boys with iron hooks were useful in controlling the loops4 ,later it was found advisable to have each succeeding mill speeded enough to take the rod as the preceding pair of rolls delivered it2 then the loops remained of approximately constant length4 ,illustration3 ,,plan ,,of ,a ,,modern ,,looping ,,mill 7,,the ,,garrett ,,mill7 ,to push production the mill was run faster and faster4 ,as longer rods were rolled1 a hand-operated reel was devised to which the boy attached the forward end of the rod while another turned the reel4 ,but the speed of the mill was limited mainly because of the slow reel and the awkward method of getting the rod attached to it4 ,the ,bedson ,continuous ,mill ,about #ahfg ,george ,bedson of ,england1 invented the first 8continuous0 mill4 ,instead of looping the rod around and back through the rolls he put several sets of rolls each in front of the other with every other pair vertical4 ,this alternate horizontal and vertical roll arrangement was necessary because the reduction of the billet or rod in any pass can be only in a direction perpendicular to the axis of the rolls4 ,the roller and catcher had given it a quarter-turn twist each time they started it into the two-high rolls4 ,bedson's successive pairs of rolls were set close together1 each pair being speeded enough that it took the rod exactly as fast as the preceding pair delivered it4 ,the billet or rod1 therefore1 traveled through them in a straight line4 ,this continuous process was1 of course1 of great advantage in that considerable speed could be attained and there was not the rapid cooling nor the opportunity for loss by scaling from exposure to the air which occurred with the long loops of the ,belgian ,mill4 ,it was a great advance1 but the speed was yet held down by the finishing pass and the inability of the reel to coil the rod fast enough4 ,the greatest development came through the inventive genius of two men1 ,charles ,morgan and ,george ,garrett1 who developed the two separate types of mill which have made the rod rolling industry what it is to-day4 ,the work of both was done in this country4 ,the ,morgan ,continuous ,mill ,morgan's also was a continuous process4 ,the billet was put in at one end of a new type of heating furnace which ,morgan devised1 and was gradually pushed along to the other end4 ,from this second or outgoing end1 the long1 narrow1 white-hot billet went through several pairs of two-high rolls set close together1 each successive pair having smaller grooves than the one preceding it1 so that1 after traversing these several pairs of rolls1 the rods emerged from the last pair finished1 having traveled in a straight line through them4 ,hand reeling was much too slow for ,morgan who invented two different types of high-speed automatic reel which1 in the highly speeded mills of to-day1 receive and coil wire coming from the finishing passes at speeds of over one-half mile per minute4 ,it is stated that the billets and rods therefrom traverse the rolls so fast and the pressure is applied so quickly and so hard that the rods emerging from the finishing passes are hotter than were the billets when they went into the rolls4 ,illustration3 ,,the ,,billet ,,traverses ,,the ,,morgan ,,continuous ,,mill ,,at ,,high ,,speed ,,emerging ,,from ,,the ,,last ,,roll ,,as ,,finished ,,rod ,as was explained1 no reduction in thickness is brought about by the sides of the grooves in the rolls4 ,therefore1 a bar or rod must be turned after each pass unless ,bedson's alternating horizontal and vertical rolls are used4 ,this turning ,morgan did in spiral tubes inserted between the successive sets of rolls1 all of which were horizontal4 ,these tubes operate as does the 8rifling0 in a gun barrel1 in turning the rod4 ,in ,bedson's mill1 with its alternating horizontal and vertical pairs of rolls1 it was possible to roll only one rod at a time4 ,with ,morgan's system1 in which all rolls were horizontal1 several rods could be traversing the mill side by side4 ,with the high-speed reels and what are known as 8flying shears0 in which billets or rods can be cut to any length while going at full speed1 ,morgan's mill had come to a high stage of development4 ,it was practically automatic4 ,the ,garrett ,mill ,while ,morgan was developing his continuous mill1 ,william ,garrett was improving the old ,belgian mill4 ,garrett believed and insisted that with proper working1 rods could be rolled from billets of much larger diameter and greater weight than the long narrow billets which had been used4 ,he eventually did away with an intermediate rolling operation by using larger billets4 ,you remember that in the ,belgian mill the 8catchers0 looped the rods back into the rolls4 ,to do this work automatically ,garrett inserted between the sets of rolls looping troughs which guided the forward ends of the rods around and into the next groove in the rolls4 ,these troughs are called 8repeaters40 ,it was found that while they worked very well for looping the cross-sections known as the squares1 they were less suitable for looping the oval sections which were produced with every other pass4 ,these were better and more safely done in the old way1 i4e41 by manual labor4 ,they are generally so done to-day4 ,with the ,morgan high-speed reel1 sloping floors to better take care of the loops1 and with successive pairs of rolls each running at higher speed than the preceding pair1 the ,garrett mill has apparently kept pace with the ,morgan4 ,each has its advantages and each is used for certain classes of work4 ,for long continued runs on rod of one size the ,morgan mill can produce more cheaply1 its product is more uniform in temper and the loss from scaling is less as little of the rod is exposed while in the mill4 ,as the first pair of rolls in the ,morgan mill is set close to the furnace1 less than one-quarter of the billet is in the mill at any one time and the forward end of the billet is on the reel as finished rod before the last of the billet leaves the furnace4 ,with any process something occasionally goes wrong so that the rod does not follow the path intended4 ,in such cases misshapen or tangled rod results4 ,such spoiled billets or rods are called 8cobbles40 ,with what is known as the 8flying shears10 which in the ,morgan mill cuts the billet or rod while it is traveling at high speed1 the rear part of the piece can be cut off and saved in case of cobbling4 ,on this account the ,morgan mill is said to give less scrap than the ,garrett4 ,the ,garrett mill1 on the other hand1 gives rod which is more uniform all along in shape and diameter and it has the considerable advantage that it is quickly adaptable to change of product2 it does not require such complicated and nice adjustment as does the ,morgan mill4 ,so1 despite the greater danger to the rollers from the circling loops about them1 which occasionally become unmanageable1 the ,garrett mill is largely used4 ,,chapter ,,xix ,,wire ,,and ,,wire ,,drawing ,it may be rather disconcerting to some enthusiastic ones who assume that we ,moderns have made all the progress that is worth while to learn that so many of our supposedly new products were far antedated4 ,in the case of wire1 again1 we were antedated as much as #cj centuries4 ,the wires which were produced by the ,ancients1 however1 were usually of the noble metals1 gold and silver4 ,they were not drawn through dies as are the wires that we know1 but were hammered into shape from long1 thin strips of metal4 ,the earliest use of our 8drawplate0 method of which we find authentic mention was in the #adth century in ,germany4 ,the wire was hand-drawn4 ,machine-drawn wire was being produced in ,england as early as #aefe4 ,in the ,united ,states the wire drawing industry had become pretty well established by the middle of the #agth century4 ,as ,cort had not at this time invented the rolling process for bars and rods1 very uneven strips of metal only were available from which to draw the wires4 ,but1 even so1 with our highly developed rod mills and our present very satisfactory ,no4 #e wire rod to begin with1 our wire drawing methods are yet seemingly crude and show small advance compared with the very great progress which has been made in other lines of the iron and steel industry4 ,unlike the processes of forging1 rolling1 etc41 drawing of wire is done cold4 ,in this condition steel has its highest strength to stand the strain4 ,the rod or wire is pulled through very hard cast iron or steel dies1 the general process being well likened to pulling a rope through a small knot hole4 ,as was seen in the rolling of plates1 8cold working0 raises the strength1 lowers the ductility and embrittles steel more than does the regular 8hot working0 at the cherry-red or white heats which are usual in the forging and rolling processes4 ,if the so-called 8cold finishing0 at very low red or black temperatures affects the physical properties of plates1 it can be readily understood that cold-drawing of wire and of seamless tubes at ordinary temperatures of #gj to #ajj ,f41 must considerably accentuate the effects noted4 ,so much is this so that drawn wires and tubes have to be frequently annealed1 i4e41 heated to a good red heat for a time between successive trips through the dies1 annealing having the effect of off-setting the lowered ductility and increased brittleness which would cause the wire to break4 ,in some cases the wire has to be annealed after each pass or draft1 but oftener several passes are possible before annealing is necessary4 ,this depends largely upon the quality of the steel used and the amount of 8reduction0 attempted in each pass4 ,the raw material1 ,no4 #e soft wire rod1 which is about one-fifth of an inch in thickness1 comes to the wire-drawing plant from the rod mill4 ,this ,no4 #e rod is the thinnest which the mills have found it economical to roll1 so further pulling down in size can best be done by 8drawing40 ,illustration3 ,,before ,,drawing ,,into ,,wire ,,the ,,scale ,,must ,,be ,,removed ,,from ,,the ,,rods ,,by 8,,pickling0 ,,in ,,acid ,as all iron and steel materials which have cooled in air from a red heat are covered with a hard1 brittle scale of iron oxide1 the rod must first be 8pickled10 i4e41 digested in hot1 weak sulphuric acid1 which1 in #aj or #ae minutes so dissolves and loosens the hard surface that it can be readily jarred loose and washed off4 ,by immersion in a vat of boiling milk of lime1 the pickled rod is given a lime coating which neutralizes any acid which remains1 and1 when dry materially aids in the lubrication of the wire while it is going through the dies4 ,thorough drying1 called 8baking10 is accomplished in the dry house at #cjj or #djj ,f41 from which the rod with soft1 scaleless1 lime-coated surface goes to the 8drawing0 benches4 ,after rinsing free from the pickling acid1 the wire is often allowed to acquire a soft film of rust by spraying it with water and keeping it wet in the air for a short time before going to the lime vat4 ,this rust or 8sull0 coat itself assists in the lubrication4 ,however1 the color of the product is not as good as when the 8sull0 coat is not used1 and such wire usually goes into articles for which darker color is no drawback4 ,illustration3 ,,single ,,wire-,,drawing ,,block ,illustration3 ,a ,,wire-,,drawing ,,die ,the dies with more or less funnel-shaped holes of accurate diameter are set vertically4 ,they are of extremely hard material in order to stand as long as possible the severe service without excessive wear1 which sooner or later so enlarges the holes that the dies become useless4 ,then they must be removed and either discarded1 or1 in the case of steel dies1 the holes reduced by hammering and redrilled4 ,often the holes of worn cast iron and steel dies are enlarged to the next larger size and so used4 ,illustration3 ,,the ,,drawing ,,of ,,wire ,the loose end of each coil of rod of wire is hammered or otherwise made smaller for a length long enough to be threaded through the hole in the die and firmly grasped by tongs or 8pliers40 ,the die being firmly fastened1 the draw head1 of which the pliers are a part1 is drawn away until a sufficient length has come through that it can be attached to a revolving block or drum which thereafter continuously pulls the rod through the die and winds it into a coil about the block as it comes1 at speeds as high as #djj feet a minute4 ,as the rod passes through the box in which the die is fastened1 besides its lime or sull coating it is sometimes provided and takes up other lubricants1 such as soap1 grease1 or tallow4 ,the coil of wire is lifted off the drum and tied1 or is redrawn to wire of a smaller size4 ,after from one to several drafts1 depending upon conditions1 the wire must be annealed for several hours1 and again pickled to remove the scale formed1 washed1 lime-coated and dried4 ,for wire which must undergo many reductions or passes1 as must all small wires1 several drawings1 annealings and cleanings must be gone through with before it is down to the desired size4 ,in order to work properly and not cut the die too fast1 which would rapidly enlarge the hole and cause the rear end of the wire to be of different thickness than the forward end1 the rod or wire must be of maximum softness4 ,either under-cleaning or over-cleaning will make the metal harsh1 as1 also1 will under-baking in the dry ovens4 ,these they endeavor to avoid in preparing the rod4 ,other lubricants may be used and certain finishes or colors given to the wires4 ,such are the various white to red coatings which come from using tin and copper sulphate solutions instead of lime coatings4 ,this is more often done with fine wire than with thicker4 ,certain 8patenting0 processes make use of various methods of tempering wires by cooling in air after a last annealing4 ,not only are wires ordered to size but many times also of certain temper or grades of hardness and stiffness4 ,these various tempers are determined largely by the chemical analysis of the steel and the number of drafts after the last annealing4 ,piano wire is well known to have a very high strength1 sometimes as high as #djj1jjj pounds per square inch4 ,spring wire is rolled and drawn from higher carbon steel than is ordinary wire1 and1 through heat treatment1 the best properties are imparted to it4 ,besides being in this form used for miscellaneous purposes1 thousands of tons of wire are annually made into wire nails1 staples1 wire fence1 barbed wire1 etc41 all of which products are of ,american derivation1 with the possible exception of wire nails4 ,even this1 however1 if not originally ours we have made ours through our great production4 ,all are very speedily turned out by automatic machines into which the wire or wires feed4 ,the product drops out into boxes below or is rolled into coils as is the case of the wire fence and barbed wire4 ,the speed of the machines is so great that the eye cannot begin to follow the operation4 ,wire being so well known it is not necessary to speak of its uses1 but it will be interesting to call attention to the very extensive production of this steel product4 ,of the #cb1jjj1jjj tons of steel produced in #aiae1 for instance1 over #c1jjj1jjj tons were rods and wire1 and when we think of the length of small or even average sized wire that it takes to make a pound1 a hundred weight1 or a ton1 some slight conception of the amount of wire produced and used comes to us4 ,as the material for wire gauze and cloth1 wire rope1 cable1 piano strings1 springs of all sorts1 pins1 needles1 nails1 fence1 barbed wire1 and the myriad of other things1 wire really is one of our great products4 ,it was mentioned that piano wire had been made which had a tensile strength as high as #djj1jjj pounds per square inch1 which is six or seven times the strength of an equivalent cross-section of steel rail or plate4 ,wire is undoubtedly the strongest product which is made from steel4 ,this is why wire rope or cable is so strong4 ,it is made by twisting together many small wires4 ,though extremely recent from the standpoint of our world's history1 the building of the famous ,brooklyn ,bridge by the ,roeblings was far enough back that we likely have forgotten that each of the four big #ae-;inch cables is made up of #e1bif separate wires tied into a bundle4 ,undoubtedly the best preservative against corrosion for iron and steel is what is known as 8hot galvanizing40 ,much wire is hot galvanized4 ,in this process the wire is 8pickled0 in weak acid to remove scale1 given a soft red coating by dipping in weak muriatic acid and drying4 ,the strands of wire #bj or #cj abreast are run through a kettle of molten zinc4 ,the wires are wiped smooth and free from excess zinc by pulling them through asbestos pads4 ,a continuous coating of zinc is thus permanently left upon the surfaces of the wires which very effectively keeps them from rusting4 ,wires which have to stand severe weather conditions may not have the excess zinc wiped from them4 ,telegraph and telephone wires often have the thicker or unwiped coating4 ,very naturally the drawing of wire requires use of much greater power than the rolling of rod and the speed of drawing is nowhere near as great4 ,therefore the cost of wire is comparatively much greater than the cost of rolled products4 ,in the case of watch springs it was once computed that the product had to bring #ej1jjj times the cost of the steel from which the wire was drawn4 8,continuous0 wire drawing has not been so successful nor advantageous as was the continuous rolling of rods4 ,it has been possible in a small way and with certain grades of the product to apply the continuous process1 but1 mainly on account of mechanical difficulties1 continuous drawing of wire seems to be comparatively unimportant4 ,,chapter ,,xx ,,the ,,manufacture ,,of ,,pipe ,,and ,,tubes ,tubes of some sort have been in use by man since very early times4 ,nature provided the first ones in the way of hollow stems of shrubs1 such as alder and bamboo4 ,some of these we saw in use by the early smiths conveying the blast of air from their goat-skin bellows into the crude clay furnaces built in the hillside4 ,tubes made of clay1 stone1 lead and bored logs were also used4 ,much later pipes made of cast iron came into rather extended use for the conveyance of water4 ,the general use of gunpowder greatly accelerated the manufacture of small tubes which the smiths produced for gun barrels by hammering and welding together long1 red-hot strips of wrought iron about round rods or 8mandrels40 ,about #ahae illuminating gas came to be used in ,england for house lighting4 ,this brought a demand for tubes of considerably greater length1 which were first made by screwing or otherwise fastening together old gun barrels which were very plentiful at that period4 ,the first patents for the making of welded pipe as we know it were taken out in #ahbd and #ahbe1 the latter for the butt-welding method of pulling a narrow iron plate1 called 8skelp10 through a bell-shaped orifice which curled it and welded the edges together very much as is done to-day by this process4 ,our modern pipe of both butt-weld and lap-weld varieties is manufactured either from wrought iron or from soft steel4 ,the ,butt-,weld ,process ,illustration3 ,,early ,,water ,,pipes ,illustration3 ,,how ,,butt-,,weld ,,pipes ,,are ,,made ,from the double refined puddled iron1 in the case of wrought iron1 or from billets of soft ,bessemer or open-hearth steel1 long narrow plates are rolled4 ,the width and thickness of these plates1 which are known as 8skelps10 are exactly such as will give pipe of the desired diameter and gauge4 ,in order that the weld may be solid all along1 the skelp as it leaves the rolls has edges not exactly square but very slightly beveled1 so that the surface which is to form the interior of the pipe is slightly narrower than the other4 ,after trimming the pieces of skelp so that each has one end with a sort of point where the tongs are to take hold1 they are laid side by side in a heating furnace and left there until they have become white-hot4 ,just in front of the furnace is the 8bell10 with a second and slightly smaller one in front4 ,with strong tongs the workman reaches into the furnace and fastens onto the pointed end of a piece of the white-hot skelp4 ,hooking the handle of his tongs into the draw chain the skelp is drawn through the first and second bell1 the first bending it almost into tube shape1 the second completing the operation and pressing together the edges of the plate in the top of the bell so tightly that they weld4 ,illustration3 ,,plates ,,called 8,,skelp0 ,,are ,,first ,,rolled ,the pipe now goes through what are known as cross rolls1 the axes of which are somewhere near parallel with the axis of the pipe4 ,in these the pipe is rapidly spun around1 surface-cleaned and straightened4 ,going up a cooling incline it goes to tables where the ends are cut off and the product inspected4 ,a very important part of the inspection is the hydrostatic or water test4 ,one at a time the pieces are tightly fitted in between two water-tight caps1 water is turned into the pipe and gradually brought up to the testing pressure of #fjj pounds or more per square inch according to specifications4 ,illustration3 ,,charging ,,skelp ,,into ,,the ,,heating ,,furnace ,illustration3 ,,drawing ,,butt-,,weld ,,pipe ,pipes of diameters between and #c are usually made by the butt-weld process4 ,lap-,welded ,pipes ,pipes larger than #c1 and boiler tubes or other particularly high grade welded tubes of #b and over are usually 8lap-welded40 ,this process gives a considerably more reliable product than does the butt-welding process1 for reasons which are readily seen4 ,illustration3 ,,how ,,lap-,,weld ,,pipes ,,are ,,made ,illustration3 ,,bent ,,skelp ,,for ,,lap-,,welding ,,being ,,charged ,,into ,,furnace ,skelp for lap-welding is rolled in just the same way as is skelp for butt-welding except that the edges are 8scarfed0 or decidedly beveled so that the two edges can make a considerable lap without increase of thickness of that part of the wall4 ,these pieces of skelp are charged into the heating furnace just as occurred in the butt-weld process and1 after coming to a white heat1 they are drawn through a sort of bell or die which curves them so that one edge considerably overlaps the other4 ,back they go into the furnace to regain any heat that has been lost1 for1 to weld properly1 the skelp must be hot enough that any scale which had covered it drips off4 ,illustration3 ,,the ,,lap-,,welding ,,rolls ,,with ,,mandrel ,,in ,,position ,the welding rolls are very short rolls1 almost 8sheaves0 or wheels1 with concave edges of exactly the outside diameter of the pipe to be formed4 ,between these two rolls1 at the end of a long straight bar1 is a mandrel or projectile-shaped ball of high-speed steel over which the white-hot tube must be pushed4 ,the reheated1 curved skelp is pulled from the furnace and the forward end forced into the rolls which shoot it through and over the mandrel at high speed1 forcing together and welding under heavy pressure the overlapping edges of what was formerly the plate4 ,amid the noise and the shooting sparks an unsuspecting bystander is quite startled by the suddenness of it all4 ,while still hot the pipes pass to 8sizing0 rolls which correct any variation in inside and outside diameters4 ,the cross or straightening rolls next smooth and clean their surfaces while straightening the pipes or boiler tubes4 ,after the first trip through the welding rolls1 boiler tubes and certain other high grades of pipe go back into the furnace where they are reheated4 ,they are again put through the welding rolls to make absolutely sure of a tight weld4 ,after cooling1 the ends of each pipe are cut off4 ,because of the 8scarfing0 of the edges and the great pressure of the rolls1 it is difficult to tell where the welds occur1 the thickness of the walls being practically uniform all around4 ,lap-welded pipe of as great as #cf diameter has been made in this way4 ,illustration3 ,,pipes ,,in ,,sizing ,,and ,,cross ,,rolls ,the water-pressure test is given to all lap-welded pipe as are certain tests for tensile and torsional strengths1 and for ability to flatten without breaking4 ,in the case of boiler tubes1 a piece is cut from each end of each tube1 which must stand flanging or spreading 8cold0 and also must crush down endwise under the heavy pressure applied in the testing machine without fracture or opening of the welds4 ,the pipe may be 8threaded0 to order or shipped as it comes from the testing bench4 ,illustration3 ,,the ,,finishing ,,end ,as remarked1 both butt and lap-welded pipe is regularly manufactured from wrought iron and from steel4 ,illustration3 ,,hydrostatic ,,test ,,of ,,the ,,pipes ,it was suggested during the discussion of the manufacture of wrought iron1 that1 owing mainly to high labor costs1 wrought iron was with difficulty competing with the soft steels4 ,wrought iron is noted for its welding properties and it has always had its loyal admirers4 ,aside from its application as 8bar iron0 which always has been and still is in favor with many metal workers for miscellaneous purposes and its use as ,swedish bar iron or low phosphorus melting bar by makers of crucible steel as a base for their product1 wrought iron probably finds its next most favored place as a material for pipe as is shown by the table given in ,chapter ,,vi4 ,while not as strong as steel pipe under hydrostatic test1 many pipe users insist that1 presumably on account of its slag enclosures and cinder films which are supposed by some to surround and protect the fibers1 wrought iron pipe outlasts steel pipe when used under conditions which induce corrosion4 ,others are as strenuous in their denial of this assertion and this subject of comparative wrought iron pipe and steel-pipe corrosion is still a very live issue4 ,for many years this matter has been under investigation4 ,hundreds of tests have been made and discussed by learned societies and their committees4 ,the laboratories and testing departments1 too1 of the large pipe manufacturers and their customers1 have made extended investigations4 ,however1 the conditions under which pipe is used are so varied and the time required for any true and decisive test is so long that really conclusive results have not been forthcoming4 ,with other materials1 each condition and corrosive influence is largely a 8law unto itself10 and one wonders if such may not prove to be the case with these materials also4 ,as suggested1 a great quantity of published information giving comparative service tests is available for those who are particularly interested in this subject4 ,how much of the decline in tonnage and in percentage of the total skelp produced1 is due to the approximately #cj greater cost of wrought iron pipe and how much to satisfactory performance of its competitor must be left to you to judge4 ,fortunately pipe of both kinds is available1 meanwhile1 and one can get whichever he prefers4 ,the uses of pipe are almost innumerable4 ,great quantities are used for conveyance of water1 oils and gases1 for ice-making and refrigeration1 the heating and draining of buildings1 for dry kilns1 hospital beds and apparatus1 electric light1 railway and telegraph poles1 pipe railings1 for conduit work1 etc4 ,for many of these applications1 the seamless variety is now utilized1 however4 ,for many purposes coated pipe is highly desirable4 ,this may be by hot asphalt1 or other liquid dip1 by surface electro-galvanizing or by the hot galvanizing method of dipping in molten zinc1 by which method probably the greater portion of coated pipe is treated4 ,certain other protective coatings are used to a limited extent4 ,,chapter ,,xxi ,,the ,,manufacture ,,of ,,seamless ,,steel ,,tubes ,it is more than likely that the popularity of the bicycle1 which created the recent great demand for strong1 light and perfect tubes1 was largely instrumental in developing the seamless tube industry1 which may be said to have 8sprung up0 within the last twenty-five years4 ,previously all of the iron and steel pipes or tubes obtainable were either of the 8butt0 or 8lap-weld0 variety with the exception of those which were made from long pieces of metal by boring holes lengthwise through them4 ,tubes by this boring method are1 of course1 quite difficult and expensive to make4 ,shorter and thicker billets of steel can more easily be bored4 ,when the holes have been enlarged by pushing larger and larger-nosed rams through them in a hydraulic press1 they can be rolled down to size over a mandrel1 just as lap-welded pipe is rolled1 only in this case they are put through several times and considerably reduced in diameter4 ,in this way some of the seamless tubes are made4 ,the important starting point in all processes for seamless steel tubes is the piercing operation and it is mostly in the method of getting the first hole through the billet that they differ1 since the hot-rolling and the cold-drawing processes by which they are finished have long been known4 ,one of the most important modern processes for seamless tubes1 the ,mannesmann1 is based upon the principle that if a white-hot round steel bar is rapidly rotated between 8cross rolls10 a longitudinal rupture which is almost a hole forms along its center4 ,we may liken the motion of the bar in the rolls to the whirling of a lead pencil between the palms of our hands1 except1 of course1 that the bar is kept rotating in one direction only4 ,though something like this tendency of a steel bar to open along the center through pressure applied at two opposite points on the outside1 seems to have been known to forgemen1 the ,brothers ,mannesmann came upon the similar tendency under action of the rolls1 by accident4 ,they were ,german tool steel manufacturers4 ,a critical customer wanted perfectly round and surface-polished bars of steel4 ,they attempted to give his bars this perfect shape and smoothness by finishing them between cross rolls which spun the bars rapidly around while they were slowly passing along through the machine4 ,the pieces were perfect outwardly1 but1 much to the steel makers' chagrin1 the customer reported that the quality of the steel was not as satisfactory as that which he previously had been receiving4 ,upon investigation it was found that this cross-rolling under pressure tended to form a small hole along the center of the bar with slight cracks in the metal all around it4 ,upon this happenstance discovery is based the ,mannesmann process for piercing the bar1 which consists in pushing over a piercing head such a center-weakened piece as it comes through the cross rolls4 ,one or two modifications of the ,mannesmann piercing method are also in use4 ,the material generally used for seamless steel tubes is medium soft open-hearth steel of 4#ae to 4#be carbon4 ,it is received as billets which are rolled down and cut at the mill or they are purchased as #c to #f 8rounds0 and cut into such lengths as give proper amounts of steel for the tubes which are to be formed4 ,usually the bars cut for tubes are from three to five feet in length4 ,they are heated in a furnace and after the end has been dented at the center1 they go into the rolls4 ,illustration3 ,,piercing ,a ,,solid ,,billet ,,by ,,the ,,mannesmann ,,process ,illustration3 ,,rolling ,,down ,,the ,,pierced ,,tube ,the rolls seize the forward end of the bar and swiftly whirl it as it is slowly pulled in4 ,a piercing head of high-speed steel at the end of a stiff mandrel extends between the rolls just as we saw it in the pipe-rolling process4 ,as the forward end of the rapidly whirling white-hot steel bar pushes against this piercing head1 the piece1 weakened along its center line is pierced4 ,as neither the rolls nor the piercing head can be resisted1 it is forced through the rolls and grinds its way over the piercing head with the supporting bar1 the walls of the white-hot tube being thinned down and the piece very materially lengthened4 ,it comes out a rough tube with thick and irregular walls4 ,after its removal from the rolling mill bar upon which another and colder piercing head is placed in readiness for the next tube1 it goes to other rolls through which it is passed1 first without a mandrel inside1 and later1 with one1 until it has become somewhere near the desired size and the walls have been pulled down to the proper thickness4 ,the mandrel1 of course1 determines the size of the interior of the tube1 and the rolls1 its outside diameter4 ,some are sold in this form as hot-finished tubes after having been straightened and cut to length by removal of the ends4 ,a great deal of the seamless tubing made is given the cold finish1 i4e41 it is drawn through dies much as rods are drawn in the making of wire4 ,for cold-drawing1 one end of each tube is reduced in size over a length of a few inches1 by forging or by other means4 ,this is where the 8pliers0 are to take hold4 ,now we can never heat steel without forming upon it a brittle oxide or scale which is much harder and harsher than the metal itself4 ,during its sojourn in the heating furnace and its journey through the rolls1 therefore1 each of the tubes acquired a hard brittle surface which must be removed before the tube can be 8drawn40 ,the most practical way of removing this scale is by 8pickling0 the tube in some weak acid1 usually sulphuric 7oil of vitriol74 ,the acid dissolves some of the scale and loosens the remainder so that it can be washed off4 ,to neutralize any excess acid which clings to the tube and to aid lubrication1 it is dipped into lime-water and then dried4 ,the tube now goes to the drawing benches which are long steel frames along which a heavy steel draw chain is continuously traveling from the center toward one end4 ,anchored at the opposite end of the bench is a long bar upon which is fastened the mandrel or ball which is to determine the inside diameter of the tube in the drawing as did the mandrel between the rolls in the rolling4 ,illustration3 ,,tube-,,drawing ,,bench ,the tube to be drawn is threaded over the long rod which is anchored in place1 and the forged-down small end is pushed through the 8die10 very firmly fastened to the bench near its center4 ,the pliers take hold of the forged-down end of the tube with a vise-like grip1 and are then hooked into the draw chain4 ,the tube is thus slowly drawn through the hole in the die4 ,as these dies are of very hard material1 either hard cast iron or hardened steel with hole a little smaller than outside of the tube1 they compress the tube upon the mandrel inside and the thickness of wall is thus regulated1 the excess metal being squeezed out so that the tube is very materially lengthened4 ,tallow or grease with the lime-coat lubricate the tube1 a little being continually drawn into and through the somewhat funnel-shaped die4 ,as was the case with the 8cold finishing0 of plate and the drawing of wire1 this cold working increases the elastic limit and tensile strength of the steel4 ,so cold-finished tubes are stronger than hot-finished4 ,for many purposes such increase in strength is highly desirable4 ,the exterior of the tube is also made very smooth and uniform in diameter by the drawing4 ,illustration3 ,,how ,,tubes ,,are ,,drawn ,the cold-drawing has a disadvantage1 however4 ,it somewhat embrittles the steel1 as may be inferred from the increase in strength4 ,this is not a serious matter1 however1 unless the cold-drawing has been overdone4 ,but for smaller sizes of tubing many drawings have to be resorted to1 to reduce the steel to the size required4 ,sometimes ten or even fifteen passes are required before the tubes reach their final size4 ,in such case the tubes have to be annealed and repickled1 limed and dried after each pass or two in order to restore to the steel its ductility4 ,if this were not done the tube would eventually break in the die4 ,the last pass is through an accurate 8sizing0 die which corrects any variation in inside or outside diameter4 ,as the pulling strain which the steel will stand is limited1 too much of a reduction in size in any single pass must not be attempted4 ,as annealing1 pickling1 drying1 etc41 have to be done after every pass or two1 a considerable period of time elapses between the piercing of the billet and its final pass as a small tube4 ,for economy in handling1 tubes cannot be considered or handled singly1 but must be treated in quantity1 so this period between billet piercing and the final pass may be as much as two weeks1 possibly more4 ,the tubes must next be straightened4 ,this is done in cross rolls as has been mentioned under the manufacture of lap-welded pipe1 or in various other types of machines4 ,illustration3 ,,cupping ,,and ,,drawing ,,seamless ,,tubes ,,from ,,plates ,much seamless tubing goes into automobile1 bicycle1 and various other products for which very high grade and perfect material is desirable4 ,one of the many interesting applications of seamless tubing is its use in very fine sizes for hypodermic needles4 ,seamless tubes are easily bent1 swaged1 upset1 spun or otherwise changed in form1 as the material is ductile and there are no welds to open4 ,very large tubes are not made in the way just described4 ,they are rather made by 8cupping0 flat1 round steel plates through a die4 ,a cup is then in several successive drawings put through smaller dies1 under which treatment it grows longer each time and gets a thinner wall until it has become a long tube with the one end still closed4 ,for open ended tubes this and the upper1 open end are cut or trimmed off4 ,cold-drawing here necessitates annealing to restore ductility just as it does elsewhere and each annealing operation is necessarily followed by pickling for removal of the scale formed4 ,by rapidly spinning large tubes in lathes or other machines and the application of pressure with the proper tools and lubrication1 the walls of the tubes may be deformed4 ,in this way the ends may be expanded1 made smaller1 or completely closed4 ,by such 8spinning0 operations large tubes are made into articles of various shapes4 ,by this same 8cupping0 or hydraulic drawing of flat1 well lubricated sheets of soft steel1 seamless high-pressure gas cylinders1 steel drums1 barrels1 and the like are made4 ,,chapter ,,xxii ,,transformations ,,and ,,structures ,,of ,,the ,,steels ,it was 8,ali ,baba0 who is quoted as saying1 8,those who do not know how to take the ,philistine1 better hadn't60 or words to that effect4 ,now through these chapters we have attempted to discuss in an entirely non-technical manner the subjects presented4 ,on this account we were compelled to forego discussion of many things which are highly important and interesting but which are more or less difficult of explanation without the use of scientific terms and theories4 ,one such has been the 8mechanism0 of the hardening of steel and its opposite1 its softening by annealing4 ,for those who may desire to get a glimpse into this 8wonderland0 it is hardly fair to refrain from brief discussion of the subject just because it is technical and difficult and so may prove to be tedious to some who have little reason to be interested4 ,it seems desirable1 therefore1 to impose this more technical chapter or two that the subject of the real metallurgy of iron and the steels may at least be 8hinted at40 ,we say 8hinted at0 advisedly for it is a long1 long story1 and1 even now1 after a great many years of serious study no one has yet read it to the end4 ,we are not saying this in a discouraging way1 however1 for there seems little reason to doubt that the multitude of facts which have been disclosed through the tireless experiments and the study of hundreds of investigators have put us well on our way to the solution of this one of ,nature's great problems4 ,to those1 however1 who are not interested in the known details of 8how0 and 8why0 hardening and softening of steel is possible and why hardening of pure iron and mild steels does not and cannot take place1 we must say as would 8,ali ,baba03--8,those who do not care to study it better hadn't40 ,anyway1 the study of this rather intricate subject is conducive of 8headaches10 and perhaps it is not extremely important when viewed from the non-technical standpoint of these articles4 ,we have several times referred to the debt which civilization owes to iron and steel structural materials1 machinery and tools and particularly to those tools which have hardened cutting edges4 ,almost every one knows that hardened cutting edges are imparted to tools by sudden cooling in water or oil from a good red heat4 ,probably most of us1 too1 know that the blacksmith can again soften such tools by reheating to the same red heat and allowing them to cool slowly4 ,this he calls annealing4 ,in this softened or annealed condition a piece can readily be sawed or filed1 while in its hardened state a saw or file produces no result upon it4 ,now what are the facts1 meaning and the cause of this dual life of the alloy1 steel1 without which we would be so greatly handicapped4 ,to be better prepared to understand the answer1 let us consider three or four accompanying and closely allied phenomena which close observation of the habits of steel has disclosed4 ,the 8,point of ,recalescence0 ,if we drill a hole in a small piece of carbon tool steel which we are about to put into the heating furnace1 and if into this hole we insert the bare tip of an electric pyrometer1 this heat-measuring instrument will indicate at all times the rising temperature of the piece of steel as it heats in the red-hot muffle or chamber of the furnace4 ,as we watch the piece grow red1 the pyrometer registers #ijj1 #ajjj1 #aajj1 #abjj ,f41--gradually and uniformly indicating higher and higher temperatures4 ,illustration3 ,,apparatus ,,for ,,determining ,,the ,,critical ,,points ,,of ,,steel ,but lo6 ,something must be wrong6 ,the pyrometer needle does not now move forward but is standing still4 ,though we know that in that hot furnace the piece must be absorbing heat at the same rate as before1 yet the pyrometer needle does not budge6 ,but1 as our wonderment grows and we are still undecided as to the meaning1 the needle again begins to advance and continues again regularly and uniformly to higher and higher temperatures as though it had never taken the vacation4 ,with the piece now at a white heat1 we have proceeded far enough with the heating4 ,turning off the electric current from the furnace and allowing it to cool we again watch the pyrometer needle as the temperature of the piece in the cooling furnace gradually falls4 ,lower1 lower1 lower swings the needle1 always at a rate approximately uniform4 ,but again it suddenly stops and remains immovable1 or perhaps even rises slightly1 for a period of several seconds1 after which it resumes its uniformly-timed downward course as though nothing had happened4 ,yes1 these pauses of the needle occurred at very nearly the same marking on the pyrometer dial1 but not at exactly the same ones4 ,going up it was at #acej ,f41 and on the downward way it was at #abej ,f4 ,and you are correct in surmising that these two points are closely related4 ,they are parts of the same1 if we may so speak1 and1 in reality they represent one point which is located about halfway between them1 the divergence resulting from what is known as 8hysteresis0 or 8lag10 which means1 of course1 a 8being-behind-hand0 or tardiness4 ,for the present we may say that all carbon steels have this 8critical0 range as shown by such pauses of the pyrometer needle during heating or cooling of the steel4 ,now as the piece is most certainly continuing to absorb heat in the furnace as it grows hotter and is losing it uniformly to the air as the furnace cools1 we have no alternative but to judge that the pause of the needle on its upward way was caused by some internal affair of the piece of steel itself1 for which1 at just that stage of its journey1 it required and used for its purpose 7which was other than making itself hotter71 the heat furnished it by the furnace2 and1 that on the downward journey1 at just that same point1 it gave out again that same heat4 ,it must have been the setting free of this imprisoned heat1 if we may so term it1 which kept the piece for those few moments from cooling at the usual rate4 ,indeed1 had we conducted our experiment in a rather dark room and observed the piece closely we would have noticed that during the pause of the pyrometer the piece of steel did brighten or glow somewhat1 showing that it had extra heat from some hidden source4 ,because of this 8self-heating0 of the steel as shown by the pyrometer and the brightening1 the temperature at which the phenomenon occurs has been named the 8point of recalescence10 which means the point at which it spontaneously becomes hotter4 ,loss of ,magnetism ,now another curious thing took place had we but noticed it4 ,we all know that iron and steel are our most magnetic materials4 ,from childhood we have seen pins1 needles1 steel pens1 and various other steel or iron objects jump to a magnet held near them4 ,what1 now1 when we find that our piece of steel in the furnace when at a red or higher heat is entirely unresponsive or dead to the attraction of a strong magnet8 ,strange6 ,do you suppose that our magnet has lost its power8 ,let us see4 ,suppose that every minute or so1 while watching the pyrometer needle go slowly down again after turning off the heat1 we put the magnet to the steel4 ,continually lower comes the temperature of the piece--#aejj1 #adjj1 #acge1 #acej1 #acbe1 #acjj1 #abge ,f41--and lo6 the piece jumps1 and from this all the way down to cold it responds to the attraction of our magnet4 ,just to make sure that we are not 8seeing things10 we again start our furnace1 and1 as the steel heats1 we test it with the magnet4 ,so far there is no doubt about its being magnetic6 ,at #ijj ,f41 the pieces begins to show dark red1 at #ajjj1 #aajj1 #aaej1 #abjj1 #abej1 stronger and stronger red4 ,at all of these temperatures the steel is attracted4 ,so it is at #abge and at #acjj ,f4 ,but just as we are thinking that we must have been mistaken before1 we find that again the steel is suddenly 8dead0 to the pull of the magnet6 ,and at what temperature8 ,the pyrometer indicates #acbj ,f4 ,but was not this the same or very nearly the same reading at which the pyrometer needle paused on the way up1 and do you not remember that it was only a little below #abej ,f4 that it paused on the way down1 and the disagreement of the two temperatures we ascribed to 8lag08 ,no1 we made no mistake4 ,steel loses all of its magnetic properties at the 8critical range0 and has none above it4 ,dilatation and ,conductivity ,certain other great changes1 too1 occur here4 ,we know that most materials expand uniformly upon heating and contract as they cool4 ,steel is no exception1 but at the critical range on heating it becomes fickle and for a short space contracts instead of continuing its uniform expansion4 ,conversely1 during cooling1 it ceases its uniform contraction and suddenly dilates or expands for a short period when it reaches the critical range1 after which aberration it again resumes its old habit of uniform contraction as the temperature falls4 ,just so with its electrical conductivity4 ,at the critical range the electrical conductivity suddenly decreases abnormally as the piece gets hotter and as abnormally increases as the steel cools through the critical range on the return trip4 ,there are certain other happenings at or near this particular temperature but we will not consider them here4 ,manifestly all of this has a deep meaning4 ,recalescence ,indicates the ,hardening ,point ,you remember that we said the divergence between the going up and the coming down pauses of the pyrometer needle was due to tardiness or lag8 ,among humans habitual tardiness is not considered a desirable trait1 but it is undoubtedly through this very lag or tardiness that steel becomes so serviceable to us4 ,illustration3 ,,heating ,,and ,,cooling ,,curves ,,of ,,steel ,,with 4#i ,,per ,,cent ,,of ,,carbon ,this lag is peculiar in that it grows less the more slowly we heat or cool the steel1 and1 if the heating or cooling is done slowly enough1 the lag disappears almost entirely1 i4e41 the pause of the pyrometer needle occurs at the same temperature on the upward as on the downward way4 ,conversely1 the disagreement or split grows or widens the faster the temperature is raised or lowered4 ,here is the vital point4 ,by extremely sudden cooling1 such as quenching in water1 the lag becomes so great that it never catches up at all and any structure with its consequent properties which was brought about in the steel by the higher temperature is thus frozen or fixed and made to 8persist0 after the steel has become cold4 ,it is just at this point1 the 8point of recalescence10 that steel changes from its soft and malleable1 to its extremely hard and brittle condition4 ,if it is quenched from temperatures above this point1 it is extremely hard1 if from temperatures below it1 even those only a little below1 it is soft and ductile4 ,it is from just a little above this point1 then1 usually between #acej ,f41 and #aejj ,f41 that the blacksmith hardens his tools by plunging them into cold water4 ,illustration3 ,,heating ,,and ,,cooling ,,curves ,,of ,,steel ,,with 4#df ,,per ,,cent ,,of ,,carbon ,steels of ,other ,composition ,now it should be noted particularly that the specimen with which we have been experimenting is a tool steel of 4#ij carbon or thereabouts4 ,this is important1 for1 while all of the carbon steels show this same critical temperature1 at which occurs the point of recalescence1 those containing from 4#de to about 4#he carbon have another point somewhat higher on the temperature scale1 and steels which contain from 4#aj to 4#de of carbon have two others1 or three points in all4 ,further1 steels having less than 4#aj of carbon and iron with no carbon at all have the two upper points but no point at #abij ,f4 ,this lower one has disappeared4 ,all of this means that if instead of a piece of 4#ij carbon steel we had used one having 4#fj of carbon1 say1 we would have found two different critical ranges or points at which the pyrometer paused1 the one at #abij ,f41 and another when we got to #acfj ,f4 ,had the steel been one containing 4#cj carbon we would have discovered pauses at three different points1 viz41 at #abij ,f41 at #acie ,f41 and at #adhj ,f4 ,with very low carbon steel or with wrought iron1 the pyrometer would have registered two pauses1 one at about #acie ,f41 and the other at #afej ,f4 ,when records are carefully kept of the time which is required for the temperature to rise or lower over each and every twenty-five degree period1 say1 on the upward and downward way1 and these are 8plotted10 what are called 8heating0 and 8cooling0 curves can be drawn through the stars and dots so set down and these form a record of the behavior of the pyrometer needle at each temperature along the scale4 ,two illustrations of such curves are shown4#i ,footnote #i3 ,special apparatus is now obtainable for determination of critical points1 heating and cooling curves4 ,now if on properly spaced1 dotted1 vertical lines1 which we will let represent these various alloys1 we mark points number three1 two and one as shown by our 8cooling0 curves1 calling the topmost point three1 it is readily seen that the points are related4 ,the lines and the alloys which they represent are1 7a7 ,the wrought iron1 7b7 4#ae carbon steel1 7c7 4#cj carbon steel1 7d7 4#de carbon steel1 7e7 4#fj carbon steel1 7f7 4#ge carbon steel1 and 7g7 the steel with 4#ij carbon4 ,illustration3 ,,critical ,,point ,,diagram ,,of ,,pure ,,iron ,,and ,,the ,,steels ,of course many more cooling curves1 especially of steels with other percentages of carbon would be desirable1 but we have enough that we are safe in sketching the horizontal and oblique lines1 ,ar#a1 ,ar#b1 ,ar#c1 ,ar#cb and ,ar#cba1 through the points which we have arranged4 ,for convenience1 metallurgists everywhere mark these points ,ar#a1 ,ar#b and ,ar#c1 the first being the lower1 and ,ar#c the upper one4 ,arcm represents an upper point found in steels having more than 4#i of carbon4 ,the letter 8r0 is derived from the ,french word1 8refroidissement10 meaning 8cooling40 ,the corresponding points disclosed during heating are marked ,ac#a1 ,ac#b1 ,ac#cba1 etc41 from the word1 8chauffage0 meaning 8heating40 ,the 8,a0 apparently 8just happened40 ,before the upper critical points were known it had been used by ,tschernoff to designate the temperature at which steels harden4 ,but it must not be supposed that the skeleton which we have constructed can be fully accepted as true until it has been checked and rechecked hundreds and hundreds of times by other investigators4 ,a great many have worked upon these critical points and upon the 8freezing-point0 curves of the various alloys4 ,it was of course impossible for all of them to make their determinations in just the same manner and with exactly the same materials4 ,examination of their work and consideration of the results which they obtained show some discrepancies as might be expected1 largely probably because of difference in purity of the materials tested1 every impurity such as manganese1 nickel1 silicon1 sulphur1 phosphorus1 etc41 modifying more or less the results obtained4 ,as we discovered1 speed of heating and cooling also modify the results4 ,when we consider the difficulties which attend the making of determinations on metals and alloys at high temperatures1 the wonder is that there is such close agreement4 ,from these standpoints the differences which exist in the published results seem quite small4 ,it was but twenty years ago that the first outline was drawn and the whole 8fusibility0 or 8equilibrium diagram0 of the iron-carbon alloys given in the next chapter has practically been developed within this time4 ,but over this period of twenty or so years the points upon which these lines ,ar#a1 ,ar#b1 ,ar#c1 ,ar#cb and ,ar#cba are based have been checked many times and they are now well substantiated4 ,these lines form but a small part of the complete 8iron-carbon diagram40 ,the ,meaning of the ,points ,you remember that wrought iron and steels having less than 4#aj carbon showed no point ,ar#a1 and that in all other steels this point becomes stronger as they contain higher and higher carbon4 ,there is little doubt that the point ,ar#a exists or results from and because of the carbon of the alloy4 ,in wrought iron there is no carbon1 hence there is no point ,ar#a4 ,if the extremely low carbon steels have an ,ar#a it is so weak that it cannot be detected4 ,had we tested the 4#de carbon steel for magnetic properties we would have found that it lost magnetism at about #acie ,f41 instead of at #abij ,f41 at which temperature the 4#ij steel became non-magnetic4 ,the point ,ar#b1 then1 shows the temperature at which loss or gain of magnetism occurs4 ,the electrical conductivity change comes at neither of these points1 ,ar#a1 nor ,ar#b1 but at ,ar#c4 ,however1 with increase of carbon the line ,ar#c1 which was drawn through the points1 ,ar#c1 rapidly descends4 ,at about 4#de or 4#ej carbon content1 this line ,ar#c1 representing the changes in conductivity1 joins line ,ar#b4 ,hence in steels having 4#de carbon or more1 there is a common point1 or one which in reality is made up of both points4 ,at this common point the phenomena peculiar to each of the points occur4 ,this common line1 now called ,ar#cb1 itself lowers with further increase of carbon until1 in steels of around 4#ij carbon1 there is but the single point ,ar#cba1 and the phenomena corresponding to all three of the points occur at this one point at #abij ,f41 as we found in our experiments4 ,as points ,ar#b and ,ar#c occur in carbonless iron1 they cannot result in any way from carbon but must have to do with the iron itself4 ,from their experiences with other materials1 chemists and physicists are well acquainted with such evolutions of heat as occur at ,ar#b and at ,ar#c4 ,these heat absorptions and evolutions1 with the sudden dilatation1 gain in conductivity1 etc41 indicate that some internal change or reorganization takes place in the iron itself4 ,such changes seem to indicate what are known as 8allotropic0 modifications4 ,more familiar examples of allotropic forms of materials may be mentioned4 ,phosphorus1 for example1 may exist1 either as the 8yellow0 variety which is poisonous and so inflammable that it must be kept constantly under water1 or as the 8red0 variety which is non-poisonous and non-inflammable4 ,too1 there is carbon1 which may exist in any one of several forms such as amorphous carbon 7soot71 graphite1 and the diamond4 ,it is believed that iron1 itself1 exists in three allotropic states4 ,these have been named 8alpha10 8beta0 and 8gamma0 iron4 ,we do not need to go into this part of the great subject except to state that at ordinary temperatures and up to ,ar#b1 we have alpha iron1 between ,ar#b and ,ar#c1 beta iron1 and above ,ar#c1 gamma iron4 ,both beta and gamma iron are non-magnetic1 while alpha iron is strongly magnetic4 ,in cooling through ,ar#c1 i4e41 from gamma to beta iron1 some rearrangement of its molecules produces the dilatation or expansion and the change in conductivity which was noted above4 ,from the fact that by chemical analysis any certain steel must have the same composition in its hardened that it has in its unhardened condition1 it will readily be seen how futile it would be to expect chemical analysis to give us complete information regarding it4 ,too1 tensile strength and the other usual physical tests can hardly tell us all that we wish to know4 ,microscopic analysis or metallography1 however1 shows us internal structure of properly prepared pieces of either the hardened or unhardened alloy that we may see the actual condition or grouping of the constituents4 ,the view points given by all three of these methods1 chemical1 physical and metallographical1 are1 of course1 much better than any one or two alone4 ,the ,structures of ,quenched and ,unquenched ,steel ,we saw that the lag or tardiness is greater the more rapid the cooling4 ,along with this very great lag which is brought about by very rapid cooling comes increasing slowness1 i4e41 less ability to catch up1 as the temperature is lowered4 ,hence quenching produces such a wide lag and so slows the changes which should take place that they do not take place at all1 i4e41 the structure which the piece had at the higher temperatures cannot change but is set or fastened by the quickness of the cooling4 ,though no degree of suddenness is sufficient to set completely the structure existing at very high temperatures1 for our present purposes we can say that by quenching in cold water we can freeze or fix any structure4 ,then after we have quenched a piece of steel1 it will have when cold1 the structure which corresponded with or resulted from the temperature which it had at the moment before the quenching4 ,if so1 the microscope should give us aid4 ,illustration3 ,,illumination ,,of ,,the ,,sample ,,under ,,the ,,microscope ,by breaking off pieces of a quenched piece and very carefully and slowly grinding and polishing without heating a surface which was an interior part we find after etching that we can actually see the kind of structure which corresponded with the temperature from which the piece was quenched4 ,photomicrograph ,no4 #hj shows the appearance of a piece of hardened carbon steel4 ,note the needle-like structure under the microscope at magnification of #djj diameters4 ,this structure is characteristic4 ,the constituent1 having this needle-like appearance has been named 8martensite0 in memory of a distinguished ,european metallurgist1 ,a4 ,martens4 ,it is supposed to be 8beta0 iron1 much the hardest allotropic variety of iron1 and to hold in solution the carbon of the alloy1 either as carbon alone or as the extremely hard chemical compound1 iron carbide1 ,fe#c;,c4 ,martensite1 then1 is the extremely hard structure1 necessarily containing considerable carbon or iron carbide in solution which gives to our carbon tool steels their hardness and great usefulness4 ,unhardened steels never look like this4 ,their appearance is shown in photomicrographs ,nos4 #c;b1 #e1 #bb and #bd;a4 ,illustration3 ,no4 #hj4 ,,martensite1 ,,the ,,constituent ,,of ,,hardened ,,steel 7,magnification #djj ,diameters7 ,in unhardened steels having less than 4#ij of carbon we find two constituents4 8,ferrite0 is the name which has been given to one1 the soft and ductile constituent1 pure iron4 ,with ordinary etching the ferrite usually shows as light-colored or white grains bounded by black lines1 which1 if the patch is large enough1 give a fish-net appearance4 ,it is soft and ductile like copper1 for pure iron and pure copper are not so greatly different in malleability and ductility as one might suppose4 ,the darker and more or less triangular patches at the corners of the ferrite grains are 8pearlite10 a name originating because of their 8pearly0 appearance under the microscope4 ,how this pearly appearance comes about will be readily understood from photomicrograph ,no4 #bc;e which was taken at a magnification of #djj diameters4 ,it is seen that it results from alternate black and white layers4 ,again we must give up the idea of any finality in the things we learn or think we have learned4 ,we just learned1 for instance1 that ferrite usually was light or white in color4 ,well1 in pearlite1 as shown in photomicrograph ,no4 #bc;e1 every other plate is of ferrite but they are not the white but the black ones4 ,illustration3 ,no4 #bc;e4 ,,pearlite ,,at ,,magnification ,,of #djj ,,diameters ,you may not have understood before that color as shown under the metallographic microscope depends not so much upon actual color of the material itself as upon its ability to reflect light4 ,for metallographic observations it is necessary to have very strong illumination4 ,usually the powerful beam from an electric arc is concentrated by means of condensing lenses upon a thin disc of glass called an oblique reflector which directs the beam upon the polished and etched specimen beneath the objective of the microscope4 ,often a prism is used4 ,the rays of light returning from this highly illuminated 8field0 under observation return up through the tube and eye piece of the microscope and can be focused upon a small screen convenient for observation or upon the ground glass of the attached camera by means of which the pictures are taken4 ,unless the surface of the specimen being examined is perfectly plain and level1 not all of the vertical rays thrown down upon it will be reflected back up through the tube and eye piece4 ,those portions of the field which are absolutely at right angles to the vertical rays appear at the eye piece or upon the screen as white or light-colored portions1 while those which1 during the polishing or etching have been dug or eaten away reflect the light imperfectly or in directions other than up the tube of the microscope1 wherefore such portions show as darker or black sections4 ,the pearlite1 then1 is made up of little plates of soft ferrite alternating with others of a very much harder constituent4 ,the harder plates are much less affected during polishing and etching than are those of the softer ferrite1 hence they stand out in relief and reflect abundant rays of light1 whereas the 8dug-out0 ferrite plates reflect the light imperfectly or not at all and therefore appear as dark lines4 ,these white1 hard plates of the pearlite contain all of the carbon of the low carbon alloys4 ,they are this other constituent1 8cementite10 so named because it was first discovered in steel made by the 8cementation0 process4 ,it is a very hard and brittle substance1 hard enough to scratch glass4 ,it is the chemical compound 7,fe#c;,c71 unvarying in composition as chemical compounds always are4 ,it consists of just three atoms of iron 7#ic4d by weight7 and one of carbon 7#f4f74 ,pearlite1 therefore1 is a sort of mechanical mixture of two separate constituents1 ferrite or pure iron1 and this chemical compound1 carbide of iron1 which is called cementite4 ,pearlite is common to all unhardened steels whether of low1 medium or high carbon content and may be considered characteristic4 ,that we may understand clearly the structures of the annealed steels1 let us start with pure iron and gradually change it into higher and higher carbon steels by gradual addition of carbon4 ,pages #cbh and #cbi show such a series4 ,photomicrograph ,no4 #ii;b is open-hearth iron which is entirely made up of free ferrite4 ,in ,no4 #c;b there is considerable pearlite1 here appearing black1 though the sample of steel yet contains but 4#aj of carbon4 ,in ,no4 #e1 which is of a steel containing 4#cj of carbon1 we have more pearlite and in ,no4 #bb;c with 4#ej carbon we have yet more4 ,manifestly at this rate the comparative pearlite areas are growing so that there will soon be room for no ferrite at all4 ,in ,no4 #bc;g this has occurred4 ,this1 the photomicrograph of a steel containing 4#hf of carbon is one of the steels in which we found that the point of recalescence1 loss of magnetism1 decrease in electrical conductivity and rate of expansion take place all at the one point4 ,illustration3 ,no4 #ii;b4 ,,carbonless ,,iron ,illustration3 ,no4 #c;b4 ,,steel ,,with 4#a ,,per ,,cent ,,carbon ,illustration3 ,no4 #e4 ,,steel ,,with 4#c ,,per ,,cent ,,carbon ,illustration3 ,no4 #bb;c4 ,,steel ,,with 4#e ,,per ,,cent ,,carbon 7,magnification #fj ,diameters47 ,now as we go still farther on up in percentage of carbon content1 i4e4 7beyond 4#hf1 we have a white constituent beginning to appear as cell walls around the grains of the pearlite and this increases with increase of carbon until1 with alloys having carbon around #c1 we have a proportionately small amount of pearlite while the white areas have so increased that it appears that the more or less round patches of pearlite float in a lake of white4 ,this white which appears first as cell walls1 and later in greater and greater quantity is free cementite47 ,illustration3 ,no4 #bc;g4 ,,steel ,,with 4#i ,,per ,,cent ,,carbon ,illustration3 ,no4 #bd;a4 ,,steel ,,with #a4be ,,per ,,cent ,,carbon ,illustration3 ,no4 #cf;b4 ,,steel ,,with #b ,,per ,,cent ,,carbon ,illustration3 ,no4 #aji4 ,,white ,,cast ,,iron ,,with #c ,,per ,,cent ,,carbon 7,magnification #fj ,diameters47 ,such are illustrated in photomicrographs ,nos4 #bd;a1 #cf;b and #aji which contain #a4be1 #a4ih and #c4jj of carbon respectively4 ,while steels with the typical white1 free ferrite areas are so soft that a needle-point will plow furrows across them1 those with over #a4be of carbon have such excess of free cementite that they are very hard to scratch and too brittle to use except for special purposes4 ,illustration3 ,,austenite 7,,white7 ,,and ,,martensite 7,,dark7 ,,magnified #a1jjj ,,times ,,their ,,actual ,,size ,so during ordinary cooling from the molten alloy or the slower cooling of the steel during the annealing process1 the martensitic structure breaks down at the recalescent temperature into pearlite and ferrite 7soft iron7 if the carbon content of the steel is lower than about 4#ij1 or pearlite and the other and very hard constituent1 8cementite10 if the steel has more than 4#ij of carbon4 ,if the carbon content happens to be just 4#ij1 or thereabouts1 there is exactly sufficient pearlite to make up the total area of the field shown under the microscope4 ,another constituent which is of great interest scientifically1 though not at all commercially1 is 8austenite40 ,by quenching very high carbon steels from a very high temperature very suddenly and completely1 we can fasten the 8austenite0 structure1 which exists only at temperatures higher than martensite1 i4e41 austenite is our gamma iron with the carbon of the alloy in solid solution1 perhaps as iron carbide1 while martensite is thought to be the beta iron solid solution1 perhaps with some gamma iron mixed with it4 ,while ordinary quenching fastens structures pretty well1 it is not usually quick enough to prevent the austenite from sliding along down into martensite4 ,however1 carbon discourages such slipping1 so1 with high carbon to act as a brake1 we can fasten some of it by chilling very suddenly and completely from a very high temperature4 ,steels with #a4e of carbon and temperatures of #bjjj ,f41 or over1 are usually necessary to accomplish it4 ,however1 austenite1 after we get it1 is not as hard as martensite and we have little use for it commercially4 ,as was stated before1 martensite is the useful and proper structure for carbon steel tools4 ,illustration3 ,no4 #gc4 ,,annealed ,,steel ,,has ,,fine ,,grain 7,magnification #gj ,diameters7 ,tempering or ,drawing 8,tempering0 is done to relieve the intense brittleness of steel after quenching to martensite4 ,while we dislike to sacrifice any of the hardness1 it pays to temper or 8toughen0 the steel1 as the toolmaker calls it1 by reheating it to somewhere between #djj and #egj ,f4 ,the higher the temperature1 the freer and quicker is the change from one structure to another1 as1 for instance1 the austenite to martensite4 ,at the low drawing temperatures the changes from martensite to the pearlitic structure may be said to just creep along4 ,a second quenching then fastens it at the new structure which gives a trifle less hard but a tougher steel4 ,as you would guess1 the microscope shows on these what we may term a 8transition0 or 8breaking-down0 appearance and structures not at all definite4 ,these1 of course1 give to the steels the various degrees of hardness and brittleness and other qualities which are so desirable from the practical standpoint4 ,the production of these fine shades of temper by the practical tool maker or blacksmith may almost be considered a fine art4 ,how and ,why ,do the ,steels ,harden8 ,now1 from all of these facts1 what1 shall we say1 is the cause of the hardening of steel8 ,the explanation most generally accepted seems to be1 that1 of the three allotropic forms of iron the gamma and beta varieties are very much harder than alpha iron1 which is the one which we have in annealed steel at ordinary temperatures1 and1 of the two1 the beta is harder than the gamma variety4 ,it is thought also1 that carbon1 perhaps as carbide of iron1 is held in solution in gamma or beta iron after the quenching1 and increases the hardness proportionately with increase of the carbon content of the steel4 ,while this carbon or iron-carbide solid solution may and probably does itself confer additional hardness to the steel1 its main function is to retard or slow down the change from gamma into beta and alpha iron1 which change in carbonless iron and low carbon steels is so insistent and extremely rapid that not even the most severe quenching1 as in ice-water or liquid air1 can prevent or stop it4 ,not only do we fail to get austenite1 which is gamma iron1 until we get #a or more of carbon present and quench from very high to very low temperatures1 but we cannot even stop the transition at beta iron1 the next lower allotropic variety until we have at least 4#cj of carbon1 and1 for serviceable hardening fully 4#fj of carbon in the steel4 ,fortunately for us1 this beta form of iron is the one we want1 for it is harder and more useful than the gamma form4 ,our most serviceable constituent1 martensite1 then1 is a solid solution of carbon or iron carbide in beta iron4 ,it is magnetic but this probably results from its containing some alpha iron through incomplete stoppage of the change by the quenching4 ,as has been stated1 8tempering10 which means careful reheating to #djj ,f41 #ejj ,f41 or #fjj ,f41 allows the slight 8slipping0 of enough of the beta solution1 always eager at temperatures below the point of recalescence to return to alpha condition1 to relieve the excessive brittleness of the hardened steel4 ,illustration3 ,no4 #gb4 ,,the 8,,sorbite0 ,,grain ,,is ,,produced ,,by ,,cooling ,,in ,a ,,blast ,,of ,,air ,,after ,,annealing4 ,,it ,,gives ,,good ,,wearing ,,properties 7,magnification #gj ,diameters7 ,annealing is the complete release of beta iron and the 8trapped0 carbon which allows of their return to the normal condition of pearlite with alpha iron4 ,to accomplish this1 the hardened steel has to be heated above its point of recalescence and cooled more or less slowly4 ,different speeds of cooling give different grain size1 structures and physical properties4 ,this explanation of hardening1 which is known as the 8allotropic0 theory1 is not universally accepted1 conclusive evidence being lacking at more than one point4 ,it must be stated also that some who hold the 8allotropic theory0 of hardening doubt the existence of beta iron4 ,these contend that the so-called beta iron and martensite are only decomposition or transition forms of gamma iron and austenite4 ,two or three other theories have been more or less strongly advocated but these also suffer from lack of evidence4 ,the one which perhaps ranks next in number of advocates is the 8carbon theory40 ,its supporters contend that by quenching1 alpha iron is made to hold carbon or iron carbide in solid solution and that it is this solution of carbon or carbide which gives to the steel hardness in proportion to its carbon content4 ,others hold that the great density or strain under which quenched steel exists accounts for the hardness4 ,like many other great problems of the universe this one is not yet conclusively or satisfactorily solved1 so reluctantly does ,nature yield her secrets4 ,but while it may not have explained all of the 8whys0 and 8wherefores10 the work which investigators have done has brought about great improvement in methods of manufacture and quality of the alloys which are making our civilization greater and this ,age more wonderful4 ,,chapter ,,xxiii ,,the ,,equilibrium ,,diagram ,,of ,,the ,,iron-,,carbon ,,alloys ,it was a great day for metallurgy when it was discovered that molten mixtures were governed by the same natural laws which govern our ordinary liquid solutions4 ,probably it was because most metallic alloys are solid at ordinary temperatures and liquid only at very high ones that for so long a time we failed to suspect their similarity4 ,if a sensitive pyrometer is inserted into an ordinary solution or a molten alloy which is being gradually cooled1 it indicates the first instant that solidification 7freezing7 begins as well as the termination of the freezing period4 ,unlike the freezing of water or a pure metal1 complete solidification ordinarily does not take place at a definite single temperature but over a greater or lesser range of temperature4 ,by taking such upper and lower freezing-point measurements for many different percentage compositions of a binary 7two metal7 alloy1 for instance1 curves can be plotted which show accurately the habits of any and all of the possible combinations 7i4e41 alloys7 of those two metals4 ,such are called 8freezing-point0 curves1 and1 as we shall see later on1 a study of them will give us much valuable and interesting information4 ,such curves have been constructed for a great many alloys since the discovery of the analogy between their behavior and that of aqueous solutions led us to study alloys after the manner which physical chemists found so satisfactory for the study of ordinary solutions4 ,since the study of binary or two metal alloys is often very difficult1 it can be readily understood why the determination and interpretation of the curves of alloys which contain three1 four or more metals is a very much more serious matter4 ,much of it has to be done by methods which are long and tedious1 such as quenching and microscopic study of innumerable specimens taken during the freezing and subsequent cooling of various alloys of each series4 ,the value of the results depends upon the skill1 devotion and clear sightedness of those who carry out the work4 ,illustration3 ,,the ,,freezing-,,point ,,curves ,,of ,,the ,,iron-,,carbon ,,alloys ,the 8freezing-point0 and 8decomposition0 curves of the iron-carbon series of alloys have been brought to their present stage of development after something like twenty years of labor by investigators in many lands4 ,if we look at the diagram on page #cde1 we note at once that the curves are quite complicated4 ,even yet they are not complete for all percentage combinations of iron and carbon1 and those who have given the most time and study to the subject have not yet been able to interpret with entire satisfaction to all concerned all of the discoveries so far made4 ,without endeavoring to take up in detail the technique of the manner of their production1 which would be unprofitable for us without a great deal more of preliminary study than we have time and space to give1 we will at once examine the freezing curves of the iron-carbon alloys as now developed4 ,the works named on page #ced as references for ,chapters ,,xxii and ,,xxiii may be consulted for the various types and methods of construction and for explanation of freezing curves by those who desire to study them4 ,referring to the freezing-point diagram on page #ccf1 the upper or broad ,v-shaped line1 ,,abc1 indicates the temperatures at which the alloys of various percentages of iron and carbon begin to freeze1 and the lower one1 ,,aed1 the temperatures at which the freezing of these alloys ends4 ,from the diagram it is readily seen that pure iron 7#ajj71 has a very high freezing-point and solidifies at once4 ,iron which contains about #b of carbon begins to freeze at a much lower temperature and has a long period of solidification1 while iron with #d4c of carbon has the lowest freezing-point of the series with an extremely short solidification period or range4 ,since we have been unable to go sufficiently into the methods and technique of freezing-curve construction to be able to understand their general classification1 we must accept the statement that the curve of the iron-carbon series is really a double one4 ,the part of it that lies to the left of the dividing line ,,uv of the diagram on page #ccf1 is of the type exhibited by liquids which freeze from 8liquid solutions0 into what are known as 8solid solutions10 which by aid of the microscope are found to be homogeneous mixtures of crystals4 ,on the other hand1 alloys which lie to the right of ,,uv1 are of the type which form 8eutectics40 ,this will be described later4 ,this dividing line ,,uv1 which occurs at about #a4g of carbon1 divides the iron-carbon alloys into these two natural divisions4 ,it was the basis for calling those having #b of carbon or less1 8steels10 and those with over this amount1 8cast irons40 ,molten iron is so greedy for carbon1 that1 when it can get it1 it readily holds in solution from #g to #aj of this element4 ,but solid 7frozen7 iron cannot retain anything like this amount4 ,as we learned in the last chapter1 gamma iron is the only variety which can exist above our lines of loss of conductivity1 magnetism and recalescence1 i4 e41 ,ar#c1 ,ar#cb1 etc4 ,it is1 too1 the only variety of solid iron which is able to retain carbon in solution1 and it can retain only about #a4g of it4 ,so when molten steel containing #a4e of carbon1 say1 cools until it reaches the temperature represented by the line1 ,,ab1 which1 at its intersection with the #a4e carbon line would be at about #behb ,f41 particles or crystals begin to freeze out and float in the molten alloy4 ,as the temperature falls1 more crystals separate until1 when the temperature determined by intersection of the #a4e carbon line with the lower freezing curve1 ,,ae1 is reached1 the last of the now mushy alloy solidifies4 ,alloys of all other compositions below #a4g of carbon do just this way except that the temperatures at which freezing begins and ends are different and distinctive for each composition4#aj ,upon freezing1 every one of them retains in 8solid solution0 in the 8gamma0 iron whatever carbon it had in the liquid or molten solution4 ,but1 as stated above1 it can not be over the #a4g limit4 ,footnote #aj3 ,temperatures of beginning and end of freezing may always be ascertained by locating on the freezing-point diagram the points at which the vertical line representing the desired composition intersects and crosses the lines of the freezing-point curves--in these cases1 ,,ab and ,,ae4 ,of the iron-carbon alloys of compositions lying to the right of the line ,,uv1 we find the case to be different1 for each one of them has more than the #a4g of carbon which is the maximum amount which 8gamma0 iron can retain4 ,now the lowest temperature at which any iron-carbon alloy can exist without freezing is slightly above #bjff ,f41 and there is but one composition--#ie4g of iron and #d4c of carbon--which can survive until this low temperature is reached4 ,a content of #d4c of carbon then1 is the greatest and also the least concentration which ,nature will allow to remain molten down to this minimum temperature4 ,this #d4c carbon composition which is the lowest melting1 i4e41 the easiest melted alloy1 is called the 8eutectic0 alloy from ,greek words which mean 8well melting40 ,this eutectic composition may be said to divide or rather subdivide this group of alloys into two groups1 those containing between #a4g and #d4c of carbon1 and those which have #d4c and over4 ,as stated before1 freezing is not an instantaneous but a progressive process4 ,during the freezing period of any of these alloys which have over #a4g of carbon the still liquid portion which remains after freezing begins to become smaller and smaller in quantity as freezing progresses just as it did in alloys of the 8solid solution0 group4 ,and as ,nature allows a concentration of #d4c of carbon as the highest concentration at the minimum temperature the very last of the remaining liquid of every alloy eventually gets to this eutectic composition just before the alloy freezes4 ,those to the left of the eutectic or exact #d4c composition do so by the gradual freezing out of iron containing the maximum or #a4g of carbon1 i4e41 iron is taken out faster than carbon1 hence there is gradual concentration of carbon in the remaining liquid4 ,this goes on until #d4c is reached4 ,the compositions to the right of the line ,,wx throw out the chemical compound1 ,fe#c;,c1 which contains #f4f of carbon1 whereby carbon is eliminated faster than iron and the desired #d4c carbon alloy is arrived at from the other direction4 ,to illustrate1 take1 say1 the composition represented by the vertical line at #c carbon and #ig iron4 ,as the molten alloy cools it reaches the temperature #bccj ,f41 at which temperature the vertical line representing the #c carbon composition cuts the line ,,ab4 ,here the alloy begins to freeze by the separation of small crystals of solidifying iron containing definite amounts of carbon4#aa ,but as the carbon thus taken along by the freezing crystals of iron is always less than #a4g1 a proportionally greater amount of iron than carbon is removed from the unfrozen part of the alloy and the remaining liquid or unfrozen part1 therefore1 is left with slightly more than the #c of carbon with which it started4 ,footnote #aa3 ,the percentages of carbon carried by the particles of iron freezing at any particular temperature of the solidification range may be determined from the diagram but the works named in the reference list should be consulted for method and explanation4 ,this we must now consider another alloy with a lower freezing-point1 the reason being1 of course1 its higher carbon content4 ,at the next lower temperature1 more iron containing carbon is frozen out and the remaining liquid is again left a little higher in carbon than before4 ,in this way the continually diminishing amount of remaining liquid keeps concentrating1 forming thereby a continuous succession of alloys of higher and higher carbon content as the temperature continuously drops4 ,eventually1 of course1 the concentration of this remaining liquor becomes #d4c of carbon just before completion of the freezing at #bjff ,f4 ,illustration3 ,,the 8,,eutectic10 ,,the ,,part ,,of ,,the ,,alloy ,,which ,,solidifies ,,last 7,magnification #gjj ,diameters7 ,now with alloys containing more than #d4c of carbon1 almost the opposite occurs4 ,let us choose the one having #e carbon and #ie of iron4 ,this molten alloy cools until at #bbae ,f41 small crystals begin to freeze and form in the molten mass4 ,but1 as the liquid already has more than the favored #d4c of carbon1 it is not free iron which freezes out1 but instead1 the chemical compound1 ,fe#c;,c1 which contains #f4f of carbon4 ,this1 of course1 takes out carbon proportionally faster than iron1 hence1 at each very slightly lower temperature1 the liquid which remains unfrozen contains just a little less of carbon than did its predecessor4 ,so the constantly decreasing amount of remaining liquid progresses through a succession of compositions each containing just a little less of carbon than the previous one1 and eventually1 just before freezing we get back to the mixture which contains #d4c of carbon4 ,of course there is left unfrozen by this time only a very small amount of the alloy and it is this which has the composition stated4 ,the 8,eutectic0 ,now1 having just the composition which she wants1 whether arrived at from alloys lower or higher than #d4c in carbon1 ,nature lets this composition freeze at once in thin alternating plates which lie side by side about and among the earlier frozen crystals of the alloy4 ,the appearance of this typical eutectic formation under the microscope is shown on page #cda4 ,had we chosen the #d4c alloy itself1 neither any of the solid solution of carbon in iron nor the chemical compound1 ,fe#c;,c1 would have frozen out1 but the whole mass would have remained liquid down to #bjff ,f41 where the whole would have solidified at once in the plate-like eutectic formation just described4 ,to sum up1 iron-carbon alloys which contain less than #a4g of carbon1 in other words1 the steels1 freeze as solid solutions of carbon in gamma iron4 ,this1 of course1 is the metallographic constituent which is called austenite4 ,it is not of a definite composition as it contains whatever carbon is available up to #a4g4 ,alloys containing between #a4g and #d4c of carbon gradually freeze out this solid solution1 austenite1 more and more being formed in the freezing alloy until1 upon arriving at a concentration of #d4c of carbon for the remaining liquid1 the latter1 too1 freezes as a eutectic of alternating plates of more of this same constituent1 austenite1 and the carbide of iron1 ,fe#c;,c1 about and among the crystals of the previously formed austenite4 ,from alloys which contain more than #d4c of carbon1 iron carbide1 ,fe#c;,c1 gradually freezes out as the temperature falls1 until1 at concentration of #d4c of carbon1 the eutectic of remaining carbide and austenite forms about and among the earlier frozen carbide crystals1 always at the same temperature1 #bjff ,f41 no matter what the original composition of the alloy4 ,upon reheating1 the constituents melt in reverse order1 the eutectic liquifying first at #bjff ,f41 the remainder of the alloy gradually becoming liquid between this temperature and the temperature at which the first freezing began during cooling4 ,transformations and ,decompositions ,so far we have considered only the freezing of the iron-carbon alloys from the molten to the solid condition4 ,now what happens to them at temperatures below #bjff ,f48 ,do they remain as we left them above1 until and after they are fully cold8 ,we must now combine the little sketch which we made on page #cai1 by plotting the points1 ,ar#a1 ,ar#b and ,ar#c1 with the freezing-point diagram which we have just now been considering4 ,you remember that we found all sorts of things happening to our #j to #a4g alloys--the steels--at temperatures around #abij ,f41 #acie ,f41 and #afej ,f4 ,similarly1 a great deal happens to these other alloys1 as they cool from their solidifying temperatures downward4 ,illustration3 ,,the ,,freezing-,,point ,,and ,,critical-,,point ,,curves ,,make ,,up ,,the ,,equilibrium ,,diagram ,but for the moment considering only the steels1 i4e41 the third of the diagram to the left of the #a4g carbon line1 we remember that upon completion of the solidification of any alloy1 we had only a frozen solution of all the carbon in iron4 ,now in the bottom part of this left third of our diagram on page #cdd1 the line ,,gose does not look so very much different than the freezing line1 ,,abc1 does it8 ,it resembles it not only in appearance but also in actual experience4 ,but in this case it represents not a freezing from liquid to solid but a decomposition1 or better perhaps1 a transformation4 ,the solid solutions or alloys which contain less than 4#i of carbon give up their excess of pure iron upon getting down to temperatures lying along the line ,,gos1 by gradual decomposition of the austenite4 ,in alloys lying to the right of this 4#i carbon vertical line the austenite rids itself of excess carbon by throwing out of solid solution and freeing the chemical compound1 ,fe#c;,c1 as the line ,,se is reached and passed4 ,that is1 analogously to what occurred during freezing1 certain concentrations occur in the solid1 lower carbon alloys by gradual rejection of pure iron crystals until the remainder of the mass has exactly 4#i of carbon1 or deconcentrate in the higher ones by rejection of ,fe#c;,c until they reduce the carbon to this 4#i figure4 ,in all cases1 by the time the temperature #abij ,f41 has been reached this has been accomplished and the remaining undecomposed austenite1 now with just 4#i of carbon1 in some way splits into the alternating plate-like constituent which is shown in the cut on page #cda4 ,illustration3 ,,the ,,equilibrium ,,diagram ,,and ,,interpretation ,,as ,,now ,,tentatively ,,accepted ,this plate-like constituent we can hardly call eutectic or 8well-melting0 alloy for it1 as well as the rest of the alloy1 has been solid for a long time4 ,but being so similar in derivation and appearance to the eutectic which forms during freezing of a molten alloy1 it is proposed that it be called the next best thing1 the 8eutectoid40 ,it is often called the eutectic1 however4 ,by this time you doubtless have seen that the free iron which was thrown out of the steel having less than 4#i carbon is the ferrite which we found in the soft steels1 and that the chemical compound1 ,fe#c;,c1 of the higher carbon steels is the extremely hard constituent1 cementite4 ,the eutectoid or plate-like structure is1 of course1 pearlite1 which in the last chapter we found to consist of just these alternating plates of ferrite and cementite4 ,the ,cast ,irons ,all of the alloys lying to the right of the line ,,uv contain more than #a4g of carbon1 and1 according to our classification1 therefore1 are 8cast irons40 ,we have seen how they freeze either as eutectic alone1 as crystals of austenite with eutectic or as crystals of cementite 7,fe#c;,c7 and eutectic1 depending upon the original composition of the molten alloy4 ,at and just below the temperatures represented by the line ,,ed1 this undoubtedly represents the situation4 ,what happens to the alloys from this temperature down to normal depends upon conditions4 ,just what occurs and the mechanism of it is not definitely known except in the practical way4 ,certain it is1 the 8precipitation0 of free carbon is necessary for cast irons which are to be serviceable for usual purposes4 ,this may occur with consequent softening during the first cooling or they may be cast as 8hard iron0 and softened afterward4 ,in ,chapter ,,xi we said that silicon was a 8softener0 as its presence brought about precipitation of the carbon as graphite throughout the cast iron1 thereby softening it both by reason of the presence of the soft flakes of graphite and because it leaves so little of the carbon in the 8combined0 or hardening condition4 ,so silicon is a ready means of bringing about decomposition of the higher temperature structures as the alloys cool4 ,the speed of the cooling also exerts a very powerful influence in determining the amount of graphite which will separate4 ,other conditions being equal1 the slower the cooling1 the greater the decomposition with resulting graphite4 ,swift cooling1 even such as results from the dumping of castings from the molds while at nearly white or high red heat results in insufficient graphite and otherwise harder metal4 ,cooling of very hot castings on a cold floor or in a current of cool air has considerable hardening effect even when the composition of the alloy would otherwise give very soft and machinable metal4 ,in an extreme and very interesting case a few very hard cast iron flanges were each day found among the many thousands of habitually soft castings regularly produced4 ,each day two or three expensive 8taps0 were ruined by attempting the impossible--the machining of these pieces of hardened iron1 which1 on the outside1 looked just like all the rest4 ,it was soon discovered that two or three mold dumpers each noon and evening were warming water for 8wash-up0 by dropping into the pails a flange or two which were still white-hot after dumping from the molds4 ,the men were innocent of any intention of harm but their warm water cost several hundred dollars before their method of producing it was discovered4 ,silicon and rate of cooling are the two most powerful influences but presence of certain elements other than silicon also influences to some extent the degree of hardness4 ,however1 while silicon has a strong softening effect1 manganese and sulphur have an opposite or hardening tendency4 ,on this account the amounts of these latter elements which can be used or allowed must be strictly limited4 ,from the above it is seen that all sorts of cast iron can be produced ranging from the extremely hard1 high cementite1 white irons with low silicon content down to the very soft gray irons which result mainly because of higher silicon content and slower cooling4 ,the white irons are more or less unstable as is shown by the decomposition through which the hard1 white iron castings become 8malleable0 by annealing as was told in ,chapter ,,xii which discussed ,malleable ,cast ,iron4 ,illustration3 ,no4 #ca4 ,,gray ,,cast ,,iron ,,with ,,ferrite1 ,,pearlite ,,and ,,graphite ,,flakes 7,magnification #gj ,diameters7 ,the gray cast irons are much more stable4 ,they consist of what1 in an early chapter1 we referred to as 8steels with an impurity1 the graphite flakes40 ,they consist1 then1 of free1 soft iron or ferrite1 certain amounts of the characteristic steel constituent1 pearlite1 and the soft graphite flakes4 ,they arrive at this composition1 through breaking down of the austenite and cementite structures during the cooling1--just how not having been satisfactorily determined4 ,consistent study is being put upon this subject and several unique and long-studied possible explanations of this section of the full equilibrium diagram have been proposed and debated1 all based upon the data so far available4 ,while much information on this subject has been gained the matter is still so much in dispute that it is best for us to venture nothing definite in regard to just how the changes occur4 ,the reference books for this chapter 7see page #ced7 give quite completely the data1 theories and explanations so far available4 ,compared with the steels1 the cast irons are vastly complicated4 ,in them we have elements which occur in practically negligible amounts in the steels4 ,commercial cast irons1 for instance1 have silicon ranging anywhere from to #c1 phosphorus 4#aj to #b1 graphite #j to #c4ej1 and carbon in the combined form 7pearlite or cementite7 from #c4ej to 4#aj4 ,if these represent the majority of cast irons what about our pig irons which have #b1 #e1 #h1 #aj or even #ae of silicon1 others with #a or #b and occasionally very much more of manganese1 and still others which vary widely in phosphorus content8--for from the metallographic and physical chemistry standpoint pig irons are cast irons4 ,as we can never get perfectly pure iron-carbon alloys to experiment with1 their content of other elements1 silicon1 nickel1 phosphorus1 etc41 vitiate more or less the results obtained1 but even could such pure alloys be secured we are not greatly helped since our serviceable alloys are never such4 ,each added element brings about greater complication and one does not wonder that in the short twenty years which have elapsed since study was seriously undertaken1 metallurgical science has not entirely solved the big problem4 ,,references ,,general ,,various 8,the ,a ,b ,c of ,iron and ,steel10 ,penton ,publishing ,co41 ,cleveland4 8,the ,steel ,foundry10 ,j4 ,h4 ,hall1 ,mc,graw-,hill ,book ,co41 ,new ,york4 8,the ,metallurgy of ,steel10 ,h4 ,m4 ,howe1 ,the ,scientific ,publishing ,co41 ,new ,york4 8,the ,manufacture and ,properties of ,iron and ,steel10 ,h4 ,h4 ,campbell1 ,hill ,publishing ,co41 ,new ,york4 8,the ,metallurgy of ,iron and ,steel10 ,b4 ,stoughton1 ,mc,graw-,hill ,book ,co41 ,new ,york4 8,the ,metallurgy of ,steel10 ,harbord and ,hall1 ,charles ,griffin ,co41 ,ltd41 ,london4 8,liquid ,steel10 ,e4 ,g4 ,carnegie1 ,longmans1 ,green ,co41 ,london4 8,krupp's ,steel ,works10 ,f4 ,c4 ,g4 ,muller1 ,wm4 ,heinemann1 ,london4 8,by ,bread ,alone0 7a novel71 ,i4 ,k4 ,friedman1 ,mc,clure1 ,phillips ,co41 ,new ,york4 ,,chapter ,i 8,the ,history of the ,manufacture of ,iron in ,all ,ages10 ,james ,swank1 ,am4 ,iron and ,steel ,assoc41 ,philadelphia1 ,pa4 8,the ,materials of ,engineering--,iron and ,steel10 ,robert ,thurston1 ,john ,wiley ,son1 ,new ,york4 ,,chapter ,,ii 8,the ,honorable ,peter ,white10 ,r4 ,d4 ,williams1 ,penton ,publishing ,co41 ,cleveland1 ,o4 8,the ,iron ,ore ,resources of the ,world10 ,international ,geological ,society1 ,stockholm1 #aiaj4 8,the ,story of ,coal and ,iron in ,alabama10 ,ethel ,armes1 ,chamber of ,commerce1 ,birmingham1 ,ala4 ,,chapter ,,iii 8,modern ,coking ,practice10 ,t4 ,h4 ,byrom1 ,c4 ,lockwood ,son1 ,london4 8,coal and ,coke10 ,frederick ,h4 ,wagner 7#aiaf71 ,mc,graw-,hill ,book ,co41 ,new ,york4 8,washing and ,coking ,tests of ,coal10 ,a4 ,w4 ,belden1 ,g4 ,r4 ,delamater1 ,j4 ,w4 ,groves1 ,bulletin #cfh1 ,u4 ,s4 ,geological ,survey1 #aiji4 8,washing and ,coking ,tests of ,coal and ,cupola ,tests of ,coke10 ,r4 ,moldenke1 ,a4 ,w4 ,belden1 and ,g4 ,r4 ,delamater1 ,u4 ,s4 ,fuel ,testing ,plant1 ,st4 ,louis1 ,mo41 ,u4 ,s4 ,geological ,survey1 ,bulletin #ccf1 #aijh4 8,manufacture of ,coke and ,other ,prepared ,fuels and the ,saving of ,by-,products10 ,john ,fulton1 #aije1 ,international ,text ,book ,co41 ,pittsburg1 ,pa4 ,,chapter ,,iv 8,the ,blast ,furnace and ,manufacture of ,pig ,iron10 ,robert ,forsythe1 ,d4 ,williams ,co41 ,new ,york4 8,a ,study of the ,blast ,furnace10 ,harbison-,walker ,refractories ,co41 ,pittsburg1 ,pa4 8,the ,principles of ,manufacture of ,iron and ,steel10 ,sir ,i4 ,l4 ,bell1 ,george ,routledge ,son1 ,london4 ,,chapter ,,vi 8,the ,business ,message of the ,wrought ,iron ,bar10 ,interstate ,iron and ,steel ,co41 ,chicago4 8,the ,control of ,quality in ,every ,process10 ,a4 ,m4 ,byers ,co41 ,pittsburg1 ,pa4 ,,chapter ,,vii 8,the ,cementation of ,iron and ,steel10 ,gioletti1 ,mc,graw-,hill ,book ,co41 ,new ,york4 8,the ,fine ,steel ,industry10 ,j4 ,a4 ,mathews1 ,the ,halcomb ,steel ,co41 ,syracuse1 ,new ,york4 ,,chapter ,,viii 8,sir ,henry ,bessemer--,an ,autobiography10 ,offices of ,engineering1 ,london4 8,the ,romance of ,iron and ,steel--,the ,story of a ,thousand ,millionaires10 ,h4 ,n4 ,casson1 ,munsey's ,magazine1 ,april1 #aijf1 and on2 ,in book form1 ,a4 ,s4 ,barnes ,co41 ,new ,york4 ,,chapter ,,ix 8,the ,manufacture of ,open-,hearth ,steel ,castings10 ,w4 ,m4 ,carr1 ,penton ,publishing ,co41 ,cleveland4 8,the ,basic ,open-,hearth ,steel ,process10 ,c4 ,dichmann1 ,constable ,co41 ,ltd41 ,london4 8,a ,study of the ,open-,hearth10 ,harbison-,walker ,refractories ,co41 ,pittsburg1 ,pa4 ,,chapters ,x ,,xi 8,cast ,iron in the ,light of ,recent ,research10 ,w4 ,h4 ,hatfield1 ,charles ,griffin ,co41 ,ltd41 ,london4 8,cast ,iron10 ,w4 ,j4 ,keep1 ,john ,wiley ,sons1 ,new ,york4 8,the ,metallurgy of ,cast ,iron10 ,t4 ,d4 ,west1 ,cleveland ,printing ,publishing ,co41 ,cleveland1 ,o4 8,american ,foundry ,practice10 ,t4 ,d4 ,west1 ,john ,wiley ,sons1 ,new ,york4 ,,chapter ,,xii 8,the ,production of ,malleable ,castings10 ,richard ,moldenke1 ,the ,penton ,publishing ,co41 ,cleveland4 8,malleable ,cast ,iron10 ,s4 ,j4 ,parsons1 ,a4 ,constable ,co41 ,ltd41 ,london4 ,,chapter ,,xiii 8,electric ,furnaces in the ,iron and ,steel ,industry10 ,rodenhauser ,schoenawa 7,translated by ,vom ,baur71 ,john ,wiley ,sons1 ,new ,york4 8,the ,electric ,furnace10 ,a4 ,stansfield1 ,the ,mc,graw-,hill ,book ,co41 ,new ,york4 8,electric ,furnaces for ,making ,iron and ,steel10 ,lyon and ,keeney1 ,u4 ,s4 ,bureau of ,mines1 ,bulletin ,no4 #fg 7#aiad74 ,,chapters ,,xiv ,,xv 8,the ,manufacture and ,uses of ,alloy ,steels10 ,h4 ,d4 ,hibbard1 ,u4 ,s4 ,bureau of ,mines1 ,bulletin ,no4 #ajj 7#aiae74 8,high ,speed ,steel10 ,o4 ,m4 ,becker1 ,mc,graw-,hill ,book ,co41 ,new ,york4 8,nickel ,steel--,its ,practical ,development in the ,united ,states10 ,h4 ,f4 ,j4 ,porter1 ,cassier's ,magazine1 #aijb1 ,page #dhj4 8,chrome-,vanadium ,steel10 ,w4 ,e4 ,gibbs1 ,cassier's ,magazine1 ,june1 #aiaj1 ,page #agd4 8,vanadium ,steels10 ,j4 ,kent ,smith1 ,american ,vanadium ,co41 ,pittsburgh1 ,pa4 8,alloy ,steels in ,motor ,car ,construction10 ,j4 ,a4 ,mathews1 ,journal ,franklin ,institute1 ,may1 #aiji1 ,page #cgi4 8,on the ,art of ,cutting ,metals10 ,f4 ,w4 ,taylor1 ,trans4 ,am4 ,soc4 ,mech4 ,eng4 #aijf-bh ,no4 #c4 8,high ,speed and ,carbon ,tool ,steels10 ,machinery ,reference ,series ,no4 #aag1 ,industrial ,press1 ,new ,york4 8,alloy ,steels10 ,machinery ,reference ,series ,no4 #aah4 ,,chapter ,,xvi 8,drop ,forging1 ,die ,sinking and ,machine ,forging of ,tools of ,steel10 ,j4 ,v4 ,woodworth1 ,n4 ,w4 ,henley ,publishing ,co41 ,new ,york4 8,metal ,working10 ,hasluck1 ,david ,mc,kay1 #aijg4 8,drop ,forging10 ,machinery's ,reference ,series ,no4 #de4 8,press ,working of ,metals10 ,oberlin ,smith1 ,john ,wiley ,sons 7#aiac74 ,,chapter ,,xvii 8,the ,rolling ,mill ,industry10 ,f4 ,kindl1 ,penton ,publishing ,co41 ,cleveland1 ,ohio4 ,,chapters ,,xviii ,,xix 8,wire ,manufacture and ,uses10 ,j4 ,b4 ,smith1 ,john ,wiley ,sons1 ,new ,york4 ,,chapters ,,xx ,,xxi 8,modern ,welded ,pipe10 ,national ,tube ,co41 ,pittsburg1 ,pa4 8,the ,control of ,quality in ,every ,process10 ,a4 ,m4 ,byers ,co41 ,pittsburg1 ,pa4 8,seamless ,tubing1 ,bulletin ,no4 #ag-;,a01 ,national ,tube ,co41 ,pittsburg1 ,pa4 8,the ,manufacture of ,iron and ,steel ,tubes10 ,e4 ,c4 ,r4 ,marks1 ,van ,ostrand ,co41 ,new ,york4 ,,chapters ,,xxii ,,xxiii 8,the ,metallography of ,steel and ,cast ,iron10 ,h4 ,m4 ,howe1 ,mc,graw-,hill ,book ,co41 ,new ,york4 8,the ,metallography and ,heat ,treatment of ,iron and ,steel10 ,albert ,sauveur1 ,sauveur and ,boylston1 ,cambridge1 ,mass4 8,metallic ,alloys3 ,their ,structure and ,constitution10 ,g4 ,h4 ,gulliver1 ,charles ,griffin ,co41 ,ltd41 ,london4 ,,index ,acid linings for furnaces1 #aci1 #aef ,allotropic modifications of iron1 #cbb ,alloy steels1 #bcb ,ammonia from coke ovens1 #di ,analysis1 chemical1 #afe ,annealing malleable cast iron1 #bjc cast steel1 #bbj tool steels1 #aji1 #bcc1 #ccc tubes1 #cjg wire1 #bhe ,bar1 ,merchant1 #aed muck1 #ii ,basic linings for furnaces1 #aci1 #aef1 #bcj ,beehive charcoal1 #ch coke1 #dd ,benzol1 #di ,bessemer1 ,sir ,henry1 #abc steel1 #abc1 #bbf ,black heart malleable iron1 #bji ,blast1 #a1 #aa1 #eb1 #eh1 #agb ,blast furnace1 #i1 #aj1 #eb ,blister steel1 #aag ,blowing of ,bessemer steel1 #abh1 #bbe ,boyden1 ,seth1 #aif ,busheled iron1 #aje ,butt-welded pipe1 #bic ,by-products1 #db1 #dg ,carbon1 effect of1 on iron1 #h1 #gd1 #hc1 #hf1 #aji1 #aaf1 #ahj1 #aih1 #bcc1 #cai1 #ccg effect of1 on iron ore1 #d1 #eg ,cast iron4 ,see ,iron1 cast ,castings1 #ahi of cast iron1 #agh ,castings of malleable iron1 #aig of pig iron 7direct castings71 #hj 8rubber10 #aib of 8semi-steel10 #ahh of steel1 #bad ,cementation steel process1 #ajf1 #aab ,charcoal1 #g1 #cg1 #ie ,chemical changes during refining1 #g1 #ig1 #aai1 #abh1 #adi1 #aee1 #afj1 #bja1 #bcj ,chemistry of gas producers1 #aeh ,chromium in steel1 #bch1 #bdc ,cinder in wrought iron1 #if1 #ig1 #aja1 #cjj ,classification according to chemical analysis1 #hc of iron alloys1 #fi1 #ahj metallographic1 #gj by physical test1 #hc1 #ahh of steels1 #ajg1 #aee volumetric1 #hh ,coal1 #da1 #di ,cold finishing of steel1 #bgj1 #cjf ,coke1 #aa1 #da ,coke ovens1 #dd1 #df ,conductivity of steels1 #cae ,converters1 #abf1 #bbf ,cooling curves of steels1 #caf ,cort1 ,henry1 #aa1 #ie1 #bei ,critical temperature or range in steels1 #cae1 #cai ,crucibles1 #aah ,crucible steel process1 #ajf1 #aah1 #bbc ,cupola melting process1 #afa1 #aga1 #aih ,dilatation of steel1 #cae ,dolomite1 #ej ,drawing bench1 #bhg1 #cjf ,drawing1 effect of cold-drawing1 #bdh of tubes1 #cje of wire1 #bhd ,duplex steel process1 #aee ,electric furnaces1 #bbg ,electric steel1 #bbg ,equilibrium diagram of iron-carbon alloys1 #cce1 #cde ,eutectic1 #cdb ,eutectoid1 #cdf ,fiber of wrought iron1 #ib1 #ic1 #aja ,fluor spar1 #ea ,flux1 #ej1 #agc ,forging1 #bdh ,freezing-point curves of iron-carbon alloys1 #ccg ,fuels1 #f1 #aa1 #ae1 #cg1 #id1 #if1 #aai1 #acj1 #aeg1 #agj ,furnaces1 air1 #aih ,bessemer converters1 #abc1 #bbf ,catalan1 #g ,cementation1 #aae ,cupola1 #aga early types of1 #f1 #ic electric1 #bbg open-hearth1 #adb puddling1 #ie ,siemens-,martin1 #adb ,talbot1 #aec ,gas1 coke oven1 #da1 #dg natural1 #aeg producer1 #aeg ,hadfield1 ,sir ,robert1 #bce ,hammers for forging1 #bdi ,hardening1 air or self1 #bda ,hardening of steels1 #aji1 #bcc1 #bdj1 #caf1 #ccc ,holley1 ,alexander ,l41 #abg ,huntsman crucible melting process1 #aj1 #aah ,ingots1 steel1 #bde ,irons1 8black heart0 malleable cast1 #bji ,busheled1 #aje cast 7,see also ,semi-steel71 #g1 #gi1 #afj1 #agh1 #cdf classification of1 #fi1 #hi early history of1 #a1 #d1 #ia ingot1 #ge malleable1 #d1 #abc malleable cast1 #ha1 #aie pig1 #fc puddled1 #ge1 #ia strengths of the iron alloys1 #hc1 #ahh ,swedish1 #ic white1 #ha1 #ahd1 #aih 8white heart0 malleable cast1 #ba wrought1 #ge1 #gg1 #ia wrought1 early processes for1 #d1 #ic ,kelly1 ,william1 #abd ,lap-welded pipe1 #bif ,lime1 use of1 #aci1 #adi1 #bcj ,limestone as flux1 #ej1 #agc ,linings1 acid and basic1 #aci1 #aef1 #bcj of ,bessemer converters1 #aci of electric furnaces1 #bcj of open-hearth furnaces1 #adh of puddling furnaces1 #ig ,magnetism1 loss of1 in steels1 #cad ,manganese1 #ace1 #aea ,hadfield's manganese steel1 #bce ,mannesmann process for billet piercing1 #cjb ,melting points of iron-carbon alloys1 #d1 #f1 #hc1 #id1 #adb ,metallography1 #gj1 #ahj1 #cbd ,metalloids1 #hf1 #hi1 #abh ,mills4 ,see ,rolling mills ,mixer1 #aca1 #aec ,molds and ,molding1 #ac1 #ahi1 #bah ,muck bar1 #ii ,mushet1 ,robert ,f41 #ace1 #bdj ,nasmyth1 ,james1 #bea ,nickel in steel1 #bcg ,open-hearth steel process1 #adb1 #bbc ,ore1 iron1 #c1 #ag1 #ec1 #add ,mesaba1 #bf unloaders1 #ca use of 7iron oxide71 in refining processes1 #ig1 #adi1 #bcj ,phosphorus in iron and steel1 #ig1 #aci1 #add1 #aeb1 #bcj ,pickling of steel1 #bhe1 #cje ,piercing of steel billets for tubes1 #cjb ,pig bed1 #fa ,pig iron1 #fc castings 78direct castings071 #hj ,pipes and tubes1 early1 #bib ,pipes1 butt-welded1 #bic lap-welded1 #bif in steel ingots1 #bde ,plates1 making of steel1 #bfd ,press1 forging by hydraulic1 #bef ,puddling of iron1 #ig ,rails1 rolling of1 #ach1 #bgc ,reaumur1 #aae1 #aie ,recalescence1 #caa1 #caf ,recarburization1 #ace1 #aea ,references1 #cej ,regenerative system of heating1 #adf ,risers on steel castings1 #bai ,rods1 rolling of1 #bgg ,rolling mills1 #bei1 #bgg1 #bid1 #cjd ,rolling of muck bar1 #ii of rails1 #ach1 #bgc of rods1 #bgg ,rolling of skelp for pipe1 #bic of steel plates1 #bfd1 #bfh ,rolling vs4 forging of steel1 #beh ,segregation in steel ingots1 #bdf 8,semi-steel10 #gh1 #ahe ,sheets1 rolling of1 #bgc ,siemens-,martin steel process4 ,see ,open-hearth ,silicon in iron-carbon alloys1 #hc1 #abj1 #acc1 #afh1 #ahb1 #cdf ,skelp for pipe1 #bic ,slag and cinder1 #ef1 #eh1 #if1 #ig1 #aea ,spiegeleisen addition in ,bessemer process1 #ace ,squeezer for puddled iron1 #ii ,steam hammer for forging1 #bea ,steels1 acid1 #aci1 #aef alloy1 #ajg1 #bcb annealing of1 #aji1 #bbj1 #bcc1 #bhe1 #cjg1 #ccc basic1 #aci1 #aef1 #bcj ,bessemer process1 #abc1 #aed1 #bbf blister1 #aag carbon1 #ajg castings4 ,see ,castings of steel cementation1 #ajf1 #aab chrome1 #bch classification of1 #ajg1 #aee crucible1 #ajf1 #aah1 #bbc duplex1 #aee electric1 #bbg hardening of1 #aji1 #bcc1 #bdj1 #bda1 #caf1 #ccc high-speed1 #ajg1 #bdj manganese1 #bce nickel1 #bcg open-hearth1 #ajg1 #adb1 #bbc place in the iron family1 #gh 8semi-steel10 #gi1 #ahe shear1 #aah structures1 decompositions and transformations of1 #caj1 #ccg1 #cdc tool1 #ajg1 #bdj tungsten1 #bcf1 #bdc ,wootz1 ,damascus1 ,toledo1 etc41 #h1 #aba ,strengths of iron-carbon alloys1 #hc1 #ahh of steel plate1 #bgj of wire1 #bij ,structures of the irons and steels1 #caj1 #cbc1 #ccg1 #cdc ,see also ,metallography ,sulphur in fuels and alloys1 #dj1 #dc1 #ie1 #ig1 #aee1 #afh1 #bjc1 #bcj ,tar1 coal1 #dh ,taylor1 ,frederick ,w41 #bda ,tempering of steels1 #aji1 #bdj1 #cca ,titanium in steel1 #bcd ,tools1 #c1 #ajg1 #bab ,tool steels1 carbon1 #ajg high-speed1 #ajg1 #bdj ,tubes and tube making1 #cjb ,tungsten in steel1 #bcf1 #bda ,uses of irons and steels1 #ga1 #hc1 #ahd1 #bab1 #bac1 #bae1 #bdi ,vanadium in steel1 #bce1 #bdc ,welding rolls1 #big ,welding of steel1 #hc1 #bid1 #bif 8,white heart0 malleable cast iron1 #baj ,white iron1 #ha1 #ahd1 #aih ,white1 ,maunsel1 #bda ,wire1 drawing of1 #bhd ,wootz steel process1 #h1 #aba ---------------------------------------- -------------------------------- ,,transcriber',s ,,notes #a4 ,silently corrected palpable typographical errors2 retained non-standard spellings and dialect4 #b4 ,reindexed footnotes using numbers4 #c4 ,enclosed italics font in underscores4 #d4 ,enclosed bold or blackletter font in equals4 #e4 ,denoted superscripts by a caret before a single superscript character or a series of superscripted characters enclosed in curly braces1 e4g4 ,mr4 or ,mister4