The Iron Age 1935-10-10: Vol 136 Iss 15

FRITS FRANK, President. VAN DEVENTER LACHER Managing Editor GERKEN News Editor MILLER Machinery Chicago Cleveland Emeritus Washington JR. Pittsburgh Detroit Boston Cincinnati CHESTNUT AND S6TH STREETS, PHILADELPHIA, PA. Sales Offices 239 WEST 39TH STREET NEW YORK, National Metal Congress, Chicago, EPORT exhibition and sessions the American Society for Metals, the American Welding the metals and the iron and steel divisions the American Institute Mining and Engi- neers, and the Wire Association........... Statistics Metal-Working Activity.................. Construction and Equipment BAUR, General Advertising Manager DIX, Manager, Reader Service Member, Audit Bureau Member, Associated Business Papers Owned, Published and Copyrighted Published every Thursday. ® tion Price: United States and Pos- sessions, Mexico, Cuba, $6.00; Can- CHILTON COMPANY ada, $8.50, including duty; Foreign (Incorporated) $12.00 year. Single copy, cents. Executive and Publication Offices, MUSSELMAN, FRITZ FRANK, Executive Vice-President FREDERIC C. STEVENS, Vice-President JOSEPH HILDRETH, GEORGE GRIFFITHS, EVERIT TERHUNE, ERNEST HASTINGS, WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary Emerson Findley, 311 Union Cleveland Peirce Lewis, 1310 Woodward Ave.. Detroit Charles Landberg. Chilton Bidg.. Chestnut & 56th Sts.. Philadeiphia. Pa. Ober, 239 39th New York 4 j F tex : | BETHLEHEM STEEL PLATE ITEMS MODERN METHOD BRINGS ACCURATE CARBON CONTROL OBTAINING CARBON CONTROL How Bethlehem Assures Taking sample steel used making Bethlehem Plates, for testing the carbom- eter, galvanometer which establishes defi- nitely the carbon content the steel. Advanced methods.like this have helped establish Bethlehem’s reputation maker plates unvaryingly high quality. PROMPT SHIPMENT FLANGED HEADS Bethlehem’s flange shop, located near the plate mills and open-hearth fur- naces, equipped give exception- ally prompt service flanged flanged-and-dished heads. in- stance this service, order for forty 64-inch-diameter tank heads was shipped within hours after was received. Even though the necessary steel plates have rolled, discs cut out, and heads flanged and dished, it’s not uncommon for Bethlehem complete and ship orders substantial size within from hours after their receipt. That’s why many buyers flanged and dished heads turn Bethlehem when heads are needed hurry. J 12—THE IRON AGE, October 10, 1935 Analysis, Steel for Plates Control carbon content which results exceptional uniform- ity obtained melts for Bethlehem Steel Plates modern method, used all Bethlehem plate-making units. Samples the molten steel, taken intervals during the melt, are subjected analysis the carbometer, which gives reading based magnetic properties rapidly cooled specimen. Its accuracy equal greater than the generally used combustion carbon method, which required many times the time necessary for the carbom- eter. far more accurate than the melter’s fracture test and quite rapid. Less than two minutes elapse between tak- ing the test sample and read- ing the accurate result. This test important aid producing plates unvary- ingly high quality, with the clos- est possible adherence the analysis. PLATE RESIST WEAR This coke-handling operation illustrates one the many applications Bethlehem Abras- ive-Resisting Plate. USERS PLATE RESIST WEAR REPORT SAVINGS Bethiehem has developed abrasive- resisting plate which effecting sub- stantial savings for operators equip- ment handling abrasive materials. Low first cost and long wear are outstanding advantages this new plate. Known Bethlehem Abrasive- Resisting Plate, carbon-man- ganese-silicon combination, costing little more than plate ordinary steel. “This the best plate have found for resisting reports one user. order handle the same amount material (gravel) would have had replace ordinary steel plates least five times.” Users Bethlehem Abrasive-Re- sisting Plate now include coal and metal mines, gravel and sand plants, brick and other ceramic industries, and operators cement and road- building equipment. This being used for scraper blades, chutes, loaders, conveyors, mixers, shovels, dump truck bodies, car bottoms, and many similar applications. — a | — | ‘ 7 | | t ? THE IRON AGE OCTOBER 10, 1935 ESTABLISHED 1855 Vol. 136, No. New Lamps for Old you remember, possessed magic lamp. was old one and not bright and shiny like the new models, but possessed powers that the new lamps did not. When rubbed his magical lamp, genie appeared and carried out any wish that Aladdin cared make. You may also remember how Aladdin's wife was tricked magician, who coveted the lamp and who obtained possession disquising himself peddler and offering shiny new lamps exchange for old ones. believe strongly the policy replacing the old with the new when the new has superior qualities. But not believe would wise swap America's magical lamp for untried new one, however shiny might be, some people would have do. America's magic lamp has done things for that Aladdin's could not begin do. For one thing has raised our standard living far above that any other country the world. has made American wages the highest the world buying power. has given Amer- ican workers the shortest work week any country. Its efficacy has been apparent even after four years depression, for what other country could have staked its idle, have, the tune The average American relief today lives better and eats more than most the employed workers countries that have exchanged their old lamps for new ones. Our magical lamp the democratic system free enterprise and initiative under the profit and loss system. The old New Englanders had name for it. They called the spirit and certain breed Americans (it comes hard call them that) wants exchange this spirit and git" for the spirit down and take.” Lay down your personal liberty and take what the dictator the Comintern says that you can shall have. Surrender your privilege quitting boss that you not like and your chance finding another that will treat you better for the doubtful privilege having boss that you cannot quit. Lay down your right make your own decisions for the questionable reward man who willing regimented the price security should join the army. will relieved the problems choice return for three square meals day and little spending money. And that return, the way, lot more than the present day reward the Russian citizens, who traded their old lamp for new one some years ago. | | q a { | | Grain Size and Influence McCARTHY ° work recent years has thrown new light the differences inherent properties heats steel and the influence these properties the reactions which occur the result heat treatment. this article, the first two-article series, the author describes method which some these properties can determined and shows their influence the manufacture wire. For the sake brevity the author confines his entire discussion high-carbon wire, not with any intention minimizing the importance low-carbon wire, but because the properties discusses are those brought out heat treatment and therefore not noticeable steels low carbon. THE successful manufacture extent the amount trouble encountered process- ing. Steel which does not respond uniformly the treatments em- ployed will lower the standards quality and, because the extra handling often required, prove costly. Uniformity product, both individual coils and from day day, necessary for the success- ful operation the wire drawing department. Much time and study have been given the chemical analysis and, while the analysis within reasonable limits import- ant, the part plays can de- termined providing other vari- ables are encountered. are all more less familiar with the fact that all heats prac- tically the same analysis not act alike. This true the open- hearth well the wire mill. Because the need common test which the effects practices the open-hearth could traced *Presented members the Wire Association Wednesday, Oct. the Hotel Congress, Chicago. A.I.M.E., Volume 67, 14—THE IRON AGE, October 10, 1935 the wire mill, there has been very little helpful exchange be- tween these two departments. method grading heats steel other than analysis has been developed, the use which helps classify the steels being used the wire mill—this method grad- ing known the McQuaid-Ehn grain size test. The McQuaid-Ehn grain size test developed its originators, Messrs. McQuaid and con- sists carburizing treatment which the samples being tested are heated for hrs. temperature 1700 deg. and allowed cool slowly. The absorption carbon resulting from this treatment sufficient materially increase the carbon content the outer edge case, thereby producing hyper- eutectoid (carbon over 0.90) area containing free cementite (iron carbide). When steel the carburizing “solid solution,” metallographically termed austenite. The grains that exist this temperature are known austenitic grains. Slow cooling from the carburizing tem- perature results the precipita- tion free cementite which forms envelopes around the grains. McQuaid-Ehn grain size based study the size and number the austenitic grains, shown the cementite markings the hyper-eutectoid area. study the hypo-eutectoid area the case hypo-euctectoid (carbon below 0.90) steels may also employed indicate the aus- tenitic grain size. this case free ferrite precipitates out solid solution cooling, forming en- velopes around the grains much the same manner does the ce- mentite the hyper-eutectoid area. customary, however, employ the hyper-eutectoid area when McQuaid-Ehn grain size referred to. The free cementite that surrounds the grains aus- tentite termed pro-eutectoid ce- mentite and the free ferrite, pro- eutectoid ferrite distinguish them from the cementite and the ferrite the pearlite. better conception the pre- cipitation ferrite and cementite can obtained study the iron-carbon diagram shown Fig. The line PSK designated the lower critical; below this line have pearlite, ferrite and pearlite, cementite and pearlite, depending the analysis. The point the eutectoid point and corresponds 0.90 cabon, the line the solubility ferrite differ- ent temperatures and the upper critical when hypo-eutectoid steels are being treated. The line designated Acm represents the solubility cementite different temperatures and the upper critical when hyper-eutectoid steels & 4 : ¢ O aN, 7 4 ° | | | q j | are being treated. The line this discussion and therefore need not considered. The dot- ted line GPN, the exact position which may vary, indicates the solubility cementite ferrite and important the develop- ment areas massive cemen- tite abnormal steels. When steel being heated the letter used after indicate heating and the letter when the steel being cooled indicate cooling. When steel heated Acl the pearlite transforms austenite; above this line the excess constit- uent ferrite cementite, the case may be, begins dissolve form what termed solid solu- tion carbon gamma iron (austenite). The solution proceeds along the lines and SE. This alters the carbon content the solid solution until above Ac3 Acem will correspond the car- bon content the steel being treated. cooling the reverse takes place and the temperature ing the analysis, the free fer- rite free cementite begins precipitate out solution, precipi- tation proceeding along the lines G’S’, This precipitation the excess constituent again alters the carbon content the solid solu- tion until Arl has carbon content 0.90, which point transforms pearlite. The precipitated excess constitu- ent separates the boundaries the austenitic grains that existed above Arcm, forming en- velopes around the grains. Transactions American Society for Treating, Vol. 16, No. 1,. July, 19-33T. Steel Wire this manner that the structures the McQuaid-Ehn grain size tests are developed. The solubility the cementite ferrite indicated the dot- ted line GPN results delayed precipitation cementite which retards the formation pearlite separating out after the has been passed. Abnormal Steels Described The McQuaid-Ehn grain size test, besides showing the size the austenite grains, may also used indicate what termed “normality”. Steels which car- burizing this manner show thick irregular envelopes and which there tendency toward coal- escence the cementite, are termed abnormal, which have thin continuous envel- opes are said normal. Mc- Quaid and Ehn their early work associated abnormality with fine grain steels and while possible obtain fine grain steels that are normal, the general tendency toward abnormality. Abnormality can exist coarse grain steels well fine grain steels. Rim- med steels are always abnormal. the case coarse grain steels abnormality associated with high dissolved oxide content. fine grain steels, however, not easily accounted for. The amount residual aluminum solution the ferrite seems ex- ert influence. has shown that there carburizing and that carburizing gen will not produce abnormal structures, even though the steel highly oxidized. While this honored with the Wire Association Award for the “Most Outstanding Con- tribution the Wire Industry Dur- ing 1935." true, nevertheless evident that steels which not have great amount dissolved oxides present prior carburizing the Quaid-Ehn test not show this condition carburizing. The struc- ture obtained the use the test there- fore indicates inherent property regards normality and may used guide the selection steel. McQuaid-Ehn grain size ex- pressed terms the number grains per square inch 100 dia- meters. grain size classification using numbers from has been adopted standard the Amer- ican Society for Testing Materials’. Each number covers range grain size. Following are the grain size numbers and the ranges they cover: Grain size number speci- fies grains per sq. in. 48; 96; and grain size number includes grains and over per sq. in. 100 diameters. Steels with McQuaid-Ehn grain size number and under are said coarse grain, while those with number and over are said fine grain. The term “intermediate grain size” some- times used indicate range and and various ranges numbers are employed specify THE IRON AGE, October 10, | | ‘ q ¥ ¥ different grades steel for special Some structures obtained this test are shown Figs. and Photo (a) Fig. shows coarse grain normal steel determined this test. Photo (c), Fig. shows fine grain normal steel. Note the difference grain size between these two steels. Photos (a) and (c), Fig. show coarse and fine grain abnormal steels. While the difference microstruc- ture between the normal and ab- steels apparent, this dif- ference better observed higher magnifications. photos (b) and The analysis for the commonly de- termined elements does not in- fluence the grain size—coarse and fine grain steels can obtained over wide range analysis. very often the case, however, where steel certain type will show similar characteristics the McQuaid-Ehn test, the similarity due the practice employed the melting and deoxidizing the steel and not the analysis. example this found rimmed steels (photos (a) and (b), Fig. which are always coarse grained and abnormal. This due the fact that these steels always con- 1800 SOLID SOLUTION CARBON IN ~ FERRITE + PEARLITE TEMPERATURE - DEGREES FAHRENHEIT N Ou 02 0.3 04 os Of GAMMA IRON ~~ ~ ~ 07 806 09 1.0 1.2 1.3 14 CARBON CONTENT - PER CENT (d), Fig. and photos (b) and (d), Fig. have these same structures taken 1000 diameters. Note the thick, irregular network the abnormal steels compared with the thin continuous network the normal steels, also note the tendency toward coalescence the abnormal steels and the coarse poorly developed pearlite. the figures discussed above the fine grain steel had been treated with aluminum. Grain Size Inherent Characteristic That the grain size, deter- mined this test, inherent characteristic the steel has been definitely established. There may some variations the grain count tests from the various parts heat and after various hot and cold working operations have been employed but such varia- tions are usually not very great. Bulletin 68, Mining and Metallurgi- cal Advisory Board, Carnegie Institute Technology. IRON AGE, October 10, 1935 tain large amount dissolved oxides and that attempt made deoxidize them. This test presents means which inherent properties steel, not revealed the analysis, can determined and its many appli- cations have attracted widespread interest. Numerous investigations have been carried result its use and valuable contribu- tions have been made add the knowledge heat treatment, steel making and deoxidation. Its ap- plications have been made instru- mental the development higher physical properties, more controlled processes and better knowledge ferrous metallurgy general. The basic open-hearth metal charge consists varying amounts cast liquid iron and scrap. The iron may vary from cast iron quality basic iron uniform analy- sis. The scrap may the CEMENTITE + PEARLITE heavy melting variety such rails, croppings from the blooming mill, thin section which can easily converted iron oxide before the charge melted and acts ab- sorbent for sulphur gases that may the furnace. Limestone, either raw burnt, also in- cluded the charge, and usually iron oxide either the form roll scale iron ore. import- ant that some iron oxide present during the melting down com- plete the reactions which are neces- sary for the elimination impuri- ties. 1000 carbon diagram relation the critical points heating and cooling. 800 700 600 TEMPERATURE - DEGREES CENTIGRADE After the charge melted the slag should put the proper condition insure the elimination excess sulphur and phosphorus. The condition the slag may also amount iron oxide remaining the bath and advisable em- ploy some test which will indicate the approximate iron oxide content the slag. Herty has pub- lished some valuable data iron oxide which are very help- ful. careful study the charge furnace condition can obtained which gives the melter reasonable control the slag. If, however, the charge not properly selected the nature the slag may such that beyond the melter’s con- trol. Iron high silicon requires extra lime and builds exces- sive slag volume. Fine thin scrap, which oxidizes readily, will build the oxide content the bath and influence the slag. Extra ad- ditions limestone silica may used put the slag condition; 4 | | € 1900 fi Ad av 1700 Ga r av » 1600 >. > 1400 4 “Sten, Cc 3-2 1100 1000 | | . q 2—A representative group structures obtained the McQuaid-Ehn test. grain normal steel, grain size No. diameters, (b) the same structure diameters, (c) fine normal steel, grain size No. 100 diameters, and (d) the same structure diameters. uniform charge which will permit the use the right amount lime- stone. The carbon content the time melting and the rate which falls should watched care- fully, for, study the carbon behavior some knowledge the type churge desired can ob- tained which will prove helpful subsequent heats. The carbon the time melting should high enough permit sufficient time for shaping the slag. general practice when high-carbon steel being made tap the heat while the carbon falling. Therefore, some control must exercised over the melt-down carbon and the rate carbon drop come within the specification. Running the carbon down and using the ladle raise usually results high oxide content. The presence car- bon the bath, because its re- ducing action, helps prevent the absorption oxygen from the furnace atmosphere. While the carbon relatively high, oxygen absorption low. However, the carbon drops, the absorption oxygen increases. Charge Made Suit Furnace High manganese the charge helps reduce oxides and de- sirable, indication low From left respectively (a) coarse charge obtain high residual manganese. The condition the furnace may influence the melting. slow work- ing furnace may introduce oxides and, when producer gas being used fuel, seriously increase the sulphur. The charge should made suit the furnace and, the furnace working slowly, sufficient iron should charged insure relatively high carbon content the time melting. Also heavy melting scrap should used. From the above discussion obvious that the making quality steel problem which requires 3—A representative group abnormal grain structures. Reading from left right respectively coarse grain abnormal steel, grain size No. 100 diameters, the same grain 1000 diameters, fine grain steel, grain size No. 100 diameters, and (d) the same grain viewed diameters. THE IRON AGE, October 10, ‘Sigg considerable attention. The elimina- tion sulphur and phosphorus, while important, not the only consideration. The amount iron oxide dissolved the steel equal importance, the control the other elements. The iron oxide content important are seeking steel which will give uniform reaction the patenting operation. will shown later, the amount oxide removed deoxidation relative and the fact that the steel lies quiet the mold does not indicate complete deoxi- dation. grain size tests may employed the open-hearth planning the charge and working the heats. practice which produces wide variation grain size certain type ~steel indicates poor operation. using this test guide quality, steel suitable meet the needs the wire mill can pro- duced. The two views Fig. show McQuaid-Ehn tests obtained two different heats and illustrates the variations structure which may obtained without proper control the operation. These heats did not respond the patenting treat- ment and caused trouble due brittle wire. The two views Fig. show the type structures obtained heats that worked sat- isfactorily and produced high qual- ity wire. While true that this test does not tell the whole story, its use can very helpful indi- cation steel quality and can see reason why wire drawing departments should not insist its use guarantee against the introduction into their processes steel which may cause trouble. Deoxidation important step the production quality steel and based the formation, the molten metal, insoluble oxides the addition elements having greater affinity for oxy- gen than iron, The oxide iron, soluble the molten metal and influences the physical proper- ties. the addition manganese, silicon aluminum, MnO, formed and slag particles, insoluble the liquid steel, are produced. The selection suit- able deoxidizer depends its af- finity for and the rate which the product formed rises Bulletin 38, Mining and cal Advisory Board. IRON AGE, October 10, 1935 L 4—McQuaid-Ehn test poorly made heats steel. the left No. grain size and the right No. grain size. Each taken 100 diameters. the surface. Aluminum, silicon and maganese vary their affinity for oxygen the order named; therefore their deoxidation value varies. The rate which the products deoxidation rise the surface depends the size the particles. Large particles rise more quickly than small ones. According Stokes’ law, “the velocity rise actually proportionate the square the particle radius.” Products deoxidation which have melting point higher than the metal temperature, such and are solid form and therefore will not coalesce form large particles. However, strongly acid particle encounters molten basic particle the steel they will combine form slag particle larger dimension, with melting point lower than the then molten basic particle. SiO: acid, but FeO and MnO are basic, and will combine with FeO and MnO form slag low melting point. particles will not coalesce because their high melt- ing point and due the fact that they are nearly neutral point acidity basicity, there little tendency for them combine with slag low melting point and flux off. This makes the elimination from the molten steel much slower than the elimination and MnO and makes the use aluminum alone deoxidizer undesirable. Titanium also used that the product formed easily fluxed off. Aluminum Deoxidation More Complete Aluminum, because its greater affinity for oxygen, will carry the deoxidation much nearer comple- tion than silicon manganese. For many years the use aluminum has been frowned view the amount non-metallics left the steel. However the manufacture fine grain steel has become real value. The generally accepted theory the control McQuaid- Ehn grain size based the pres- ence the metal numerous finely dispersed particles re- fractory nature. Aluminum, both because its greater affinity for oxygen and its lack tendency toward coalescence, has come into general use for this purpose. The usual procedure deoxidize the metal, first the addition sili- con and manganese the furnace, followed aluminum the ladle. Aluminum added this manner carries the deoxidation further and results the formation numerous finely dispersed particles the These particles act nuclei around which the grains grow and offer obstruction grain growth. Large particles present the metal seem have little in- fluence the grain size. only after the deoxidation has been car- ried the point where the fine particles are formed that control becomes apparent. The manufacture coarse grain steels presents entirely different problem, the mechanism which not thoroughly understood. That the amount FeO present, it- self, seems have little influence shown the fact that rimmed steels, which are high FeO, are nearly always coarse grained. The degree deoxidation and the rate have influence the grain size when the steel the partially deoxidized condition. This prob- 7 a : J 3 | 5—McQuaid-Ehn test properly made heats steel. the left size No. and the right grain size Each photo taken 100 diameters. ably due the formation some fine particles that have not had time coalesce form large particles. therefore important, the working the heat, that the amount oxides the metal prior deoxidation kept nearly constant possible order ob- tain the degree deoxidation de- sired the finished steel. The production steel uniform grain size from one heat the next evidence uniformity the deoxidation. using the Mc- Quaid-Ehn test knowledge the deoxidation can obtained. stated above, the formation fluid slags the combining of. SiO. with MnO and import- ant the elimination the prod- ucts deoxidation. silicon alone added the furnace the thus formed will slag off com- bining with FeO. this may incomplete and can ac- celerated the addition man- ganese before deoxidation has pro- gressed very far. The use man- ganese the furnace, just prior tapping, desirable. While there some loss, the deoxidizing value manganese not sufficient make this loss too great. the same time MnO formed which will combine with and FeO increase the fluidity the particle. The use silicon the furnace considered desirable because af- fords time for the elimination deoxidation products. The term “killed steel” often too closely associated with deoxida- tion. The degree killing usu- ally indicated the silicon con- tent the metal. Steel with 0.05 per cent silicon said semi- killed and steel with 0.20 silicon said killed. Tests made adding varying amounts alu- minum the mold control grain size have shown that the degree deoxidation can vary considerably steels the same silicon con- tent. High-carbon steel generally more thoroughly deoxidized than low-carbon steel. This due low oxide content the steel prior deoxidation. Very often low- carbon steel containing about 0.25 silicon more highly oxidized than high-carbon steel with silicon con- tent 0.10. This proves that de- oxidation, generally employed, depends the amount oxides the metal prior deoxidation and, under fixed plan deoxida- tion, steel varying dissolved oxides can produced the metal prior deoxidation varies oxide content. study the influence alu- minum addition the steel, the cutting out the die wire draw- ing, has shown that when properly employed, that when used after silicon and manganese, effect was noted. However, oz. aluminum per ton added low- carbon steel produced consider- able amount and some cut- ting out was noticed when cast iron dies were used. This wire did not cut out when drawn through tung- sten carbide dies. Editor’s Note: Next week the author will conclude this review. The influence hot and cold work the McQuaid- Ehn grain size will described and discussed, grain coarsening tempera- tures will considered, and actual wire drawing problems will ex- amined detail. Welding Cable Designed For Severe Wear NEW type welding cable de- signed meet conditions extremely severe wear and abrasion has been brought out the Lin- coln Electric Co., Cleveland. The cable, which mar- keted Lincoln addition its well-known “Stable-Arc” electrode cable and widely used ground cable, known Realwear. Realwear cable consists fine- tinned copper wire laid ropes and stranded. Individual ropes are alternated succession regards the direction the lay prevent distortion applications severe usage. The conductor Realwear cable insulated with especially de- veloped rubber compound pro- vide firm adhesion between the cover and rubber insulation. High-grade cotton woven loom and securely joined the rubber belt special process forms the cover. The cover pro- vided with finish very resistant oil, grease, acid, gasoline, mois- ture and heat. The strength the new cable comparable that fire hose. test the wearing quality Realwear cable showed unusu- ally resistant abrasive action. The test was made tying delivery truck length Real- wear cable alongside lengths two other makes cable and allowing them drag over pavement for approximately miles. Observa- tion the end the test showed the cover the Realwear sample hardly worn through, while the other two samples were badly worn, some places completely through the copper conductors. Realwear cable supplied sizes 00, 000 and 0000. The number and sizes strands and outside diameter inches are follows: Sizes Sizes Strands No. In. 1666 0.617 2107 0.72 0 2646 34 0.77 3332 0.827 000 Hoag 5242 24 0.96 THE AGE, October AW 4 aa g q Modern was originally believed (and probably true) that aluminum was first used corrective for overoxidized heats, and was frowned being means for getting with poor furnace practice. view the present widely used although rather carefully concealed practice add- ing aluminum control hardenability, grain size, etc., and particularly the combination aluminum addition with greatly improved knowledge and control the basic open-hearth furnace itself, was felt that the status this element had completely changed recent years. This change status is, course, important user and maker steel alike, and the author's belief that the discussion this new status aluminum will general interest. Although all the information contained herein not entirely new, the arrangement has been careful and the presenta- tion proper that entire new light shed the relation aluminum additions the problems encountered users steel. MUCH has been writ- ten the subject variation the prop- erties various heats steel approximately the same analysis generally analyzed. Much has been written the ef- fect grain size, “normality,” etc., the characteristics the fin- ished part. Grain-size specification understandings have become almost universal, especially the automotive steels. But this con- sideration has not always been with the best judgment. Some our most prominent metallur- gists have changed from open scorners grain-size specifications become the most ardent advo- cates. Normalizing and annealing cycles are now predicated grain- size specifications. Machining re- sults have governed many cases the grain-size specifications, and has distortion quenching, im- pact requirements and fracture requirements, etc. most cases has been found that the extremely fine grain very *Presented Oct. the Palmer House, Chicago. 20—THE IRON AGE, October 10, 1935 abnormal types have definite ad- vantages when combined with suffi- ciently high carbon, manganese and other alloys insure satisfac- tory quenching. While this be- ing given considerable publicity the present time, the advantages the extremely fine-grained type was early recognized those closely connected with the applica- tion heat-treated alloy steel and the carbon-manganese types. Grain-size specifications have be- ered (in this country) natural requirement practice large extent gov- erned the customer’s require- ments for given part, rather than chemical analysis and sound- ness tests. Visitors from abroad who are in- terested purchasing steel, and particularly special purpose steel, are amazed the importance cen- tered this country grain-size requirements. They express con- cern over the fact that European steel producers have not yet gotten into the rather unenviable position the American steel producer trying guarantee that the steel shipped will make given part regardless design specified analysis. They not realize the revolution which has taken place behind the scenes American open-hearth steel practice per- mit the steel maker take this position. And this revolution has been one, not only open-hearth operation, but also the viewpoint and policy the management and sales department regards obli- gation the customer. Few re- alize the part played aluminum this revolution and particularly its relation general open- hearth practice and metallurgical control. For aluminum one the most difficult metals con- trol steel-melting temperature, and especially the presence these temperatures the easily reducible metallic oxides. The development the control open-hearth operations required achieve results with aluminum order produce steels defi- nite heat-treating characteristics has been achievement small moment the steel miil metallurgists. sufficient say this point that this urgent need improving open-hearth oper- ations meet the steel user’s in- sistence product uniform characteristics has resulted im- proving the basic open-hearth prod- uct the point that can made quality equal any other method producing commercial tonnage steels. The effect grain-size variation the characteristics the fin- ished steel has been well covered the past few years. Epstein and Rawdon, Hardy, Bain, Grossmann, Schane and others have discussed | | — 7 q ° ° 7 4 a | 4 q | f \ | Commercial Steels Republic Steel Massillon, Ohio the importance grain-size con- trol, but there has been little pub- lished data given the part played aluminum this work. Epstein and Rawdon their classic studies normal and ab- normal steels were the first pub- lish the importance aluminum controlling grain size and nor- mality, and Epstein, Nead and Washburn again the grain-size symposium New York last year pointed out the value aluminum this regard. Both these papers were impor- tant contributions the subject aluminum steel. Herty and his associates have pointed out sev- eral times the difference char- acteristics aluminum and silicon- killed steels. One the first ref- erences the effect aluminum deoxidation found the paper Ehn and McQuaid 1922, which the fine grain obtained the aluminum deoxidation con- trasted with the coarse grain the manganese deoxidation. Pho- tomicrographs showing this dif- ference are shown Fig. Most the investigations date have been concerned with the general effect aluminum grain size and deoxidation results general way, and have ac- cepted without much question the oxide dispersion theory the rea- son for the aluminum addition other than for straight deoxi- dation. History Aluminum Additions Before going too directly into the subject aluminum and its im- portance the steel user, well divert our attention for the mo- ment those small developments from which arose the present in- terest the subject the alumi- num addition. Occasionally days gone by, checking case-hardened parts the routine case depth fracture test, direct quenched pieces would found that did not show the characteristic coarse crystalline fracture the plain carbon steel being tested, but would show fine case with fine fibrous core frac- ture. When these appeared they were often analyzed and found the usual analysis with alloy present. could found and these pieces were spoken having some peculiar characteristics which made them “perfect” free from grain growth after long heating 1700 deg. was noted that case-hardened parts heats which showed the so-called perfect fracture were tougher and gave some more trouble harden- ing, but when most the quench- ing was done brine, little real trouble was experienced. When the quenching was changed water, Edward Mille Memorial Lecture* McQUAID however, and when, during the war, the number steel sources increased, the trouble with soft work increased greatly and indi- cated certain sources and certain heats being particular offenders. When heats were kept separate through the heat-treating depart- ment, this was point easily es- tablished. early 1919 the men charge heat treating were brought into the dark room see the ground glass screen the difference between heats which acted “normally” and those which acted “abnormally” far the preduction satisfac- tory hardened cases were con- cerned. The characteristic differ- ence between the coarse normal heats and the fine abnormal heats was obvious the men directly charge the heat treating, and became the practice divert the fine-grain abnormal heats other uses. Since they were the excep- tion, this was particular hard- ship. checking among metal- { IG. grain obtained aluminum deoxidation, contrasted with the coarse grain manganese (At Left) Hypereutectoid zone specimen from ingot deoxidized with aluminum. Right) Hypereutectoid zone specimen deoxidized with ferromanganese. Both views 200 diameters. THE IRON AGE, October 10, Le | 4 ff f % Pounds Aluminum per Net Ton Per Cent Analyzed lurgical acquaintances that time was found that this difficulty soft work the plain carbon car- burizing steel was not new, espe- cially the making camshafts and piston pins. One automobile company kept hand supply camshafts which had good hard- ening characteristics and used these check against the steel source when they were trouble. Thus, whatever the reason, the in- ability given lot steel produce good camshafts when the standard camshafts were proces- sing satisfactorily was considered sufficient cause for rejection. was soon found that the IG. Aluminum added, com- pared with aluminum analyzed. The straight cates theoretical ad- dition. 0.200 coarse-grained very normal type, while specifically good for high uniform hardness case-hardened, plain low-carbon, water-quenched steel, was not suited alloy gears and many other applications. This course was due the deeper hardening characteristics, the in- creased warpage and the decreased toughness which came with the coarse-grain normal type. was recognized far back 1922 that the finer grained types were better for gears and other alloy grades. Being position compare steel large quantities from various sources, both the plain carbon and alloy case-hardening types, normalized bars having > heat, 323; and right heat 422. All photos diameters. 22—THE IRON 10, 1935 was early recognized your lec- turer that the inherent character- istics hardenability, toughness, these steels varied from mill mill well from heat heat. The difference ductility, distortion, etc., was easily checked when making hundreds thous- ands duplicate parts case- hardened carbon steel form which permitted easy checking for ductility the hardened condition. interesting remember the many valuable discussions years ago, especially those con- cerning the use aluminum. was plainly evident 1922 that the properties case-hardened steel were very much affected the aluminum additions, and was agreed then that for some applica- tions the improved toughness made additions aluminum very desir- able. was interesting that time compare the relative tough- ness identical parts made from different heats and especially from different sources. The product was such (bearing races) that crushing tests could easily made com- pare the amount bend before fracture well the fracture, and hence many tests could made from given heat without difficulty. was soon established that the so-called coarse-grained normal steel was very brittle compared the finer grained types, and the fracture much poorer when single quenched. Since the so-called less abnormal types plain carbon steel could appar- ently successfully hardened the spray quench, then used, was decided back 1922 that the addi- tion carefully regulated addi- tion aluminum the properly killed heat was desirable insure the best combination toughness and hardness. Early 1923 was the opinion one our lead- ing alloy steel makers that the coarse-grained normal steel was undersirable for gears because increased distortion and low im- pacts. Even then was noted that the coarse-grained type would, with the normalizing equipment then available, give apparently better results machining. Aluminum Used 1922 noted before, far back 1922, the advisability adding aluminum heats improve the “toughness” the finished part was discussed. fact, records available show one steel maker 1919 adding over one pound aluminum per ton the ladle commercial nickel-chromium steel improve the “toughness.” Many cases could cited where carefully regulated combinations scrap, aluminum additions, etc., were made far back 1922. These additions were made de- velop better impact values, better fractures, less distortion, and aluminum three pounds per ton was used. Bearing steels, axle steel and gear steels were subject this control and the attention the mill metallurgist was cen- tered the alloy grades rather than the carbon grades, although certain cases, such plain high-carbon lock washer stock, etc., aluminum additions were made improve the ability distribute stresses and reduce cracking. While much work was being done the effect grain size from 1922 on, and the value applying the new knowledge was soon recognized, the means for controlling and obtaining the dif- ferent types were seldom discussed. The introduction the first grain- size chart 1924 was evidence that the very intensive study the data obtained investigating the effect deoxidation methods the characteristics the finished steel was bearing fruit. also in- dicated the value the carburiz- ing test means for indicating the characteristics expected the steel made. interesting read the dis- original paper Ehn and Mc- Quaid, which indicates the extensive manner which the car- burizing test (McQuaid-Ehn) was applied 1920-1921 the plant the United Alloy Steel Corpn. alloy steels. This work marked the first study grain size and normality know today, and soon developed the connection between the grain size and steel characteristics well the con- nection between deoxidation meth- ods and steel characteristics, witness the first grain-size chart 1924. The following taken from Schmid’s discussion the 1922 paper: “The method offers opportunities improve- ment the product itself and the selective application that product. offers opportunity for constructive study and experi- mentation the most efficient methods. deoxidation, also for the selective application heats meet specific conditions.” view what has been done since then, this statement Mr. Schmid was indeed prophetic. spite the fact that from 1922 intensive study was being made grain size, deoxidation and its relation grain size, and the relation grain size results the finished material, little any- since was soon learned most important factor trolling the effect the aluminum used was the degree oxida- tion and. the type oxides present when the deoxidizers were added. During the development the practical side making steel definite characteristics, much was being done educate the user the importance factors other 4 ah + IG. 4—Variation structure after normalizing 1800 deg. steel containing various aluminum contents. Upper left heat upper middle heat, 412; upper right, heat 313; lower left, heat 221; and lower right heat 322. All photos diameters. the so-called thing was published methods employed grain-size control. Due customer and sales pres- sure, became increasingly im- portant that mill producing spe- cial steels fully familiar with the practical problems involved producing steels having the grain manded the steel From 1922 on, many investigations were made the factors involved which affected the characteristics the final product. These investiga- tions covered every phase steel making from scrap finished product, and particular emphasis was put deoxidation control, than chemistry and soundness the relation steel specification meet certain part. all this work the importance the part played aluminum was kept very much the back- ground. only that the electric furnace steel maker, who had more stable and uniform condition oxidation his ished steel, should able ob- tain control his aluminum effect before the open-hearth man could. fact, for time, this easier con- trol uniformity oxidation and aluminum effects gave the large electric steel maker definite ad- vantage, and this advantage re- THE IRON AGE, 1935—23 4 * at J _ TABLE I—CHEMICAL ANALYSIS EXPERIMENTAL HEATS Heat 024 0.40 0.91 0.12 0.012 0.019 0.012 0.019 0.0140 522 0.40 0.95 0.15 0.011 0.030 0.032 0.030 0.0137 122 0.40 0.88 0.18 0.014 0.020 0.026 0.028 0.0142 222 0.37 0.70 0.17 0.013 0.022 0.098 0.020 0.0068 323 0.36 0.74 0.15 0.013 0.028 0.117 0.026 0.0068 422 0.37 0.72 0.17 0.020 0.025 0.204 0.023 0.0074 022 0.335 0.45 0.16 0.011 0.029 0.017 0.022 0.0135 0.33 0.44 0.19 0.014 0.023 0.013 0.027 0.0097 121 0.325 0.39 0.20 0.019 0.027 0.016 0.026 0.0091 221 0.38 0.44 0.12 0.016 0.023 0.015 0.044 0.0137 322 0.37 0.44 0.15 0.009 0.028 0.055 0.040 0.0132 411 0.26 0.41 0.09 0.009 0.020 0.173 0.029 0.0142 212 0.26 0.49 0.17 0.006 0.022 0.120 0.053 0.0124 421 0.35 0.40 0.15 0.015 0.028 0.129 0.037 0.0115 312 0.26 0.42 0.17 0.020 0.020 0.156 0.034 0.0153 III 015 0.245 1.05 0.14 0.022 0.027 0.011 0.013 0.0111 115 0.245 0.94 0.23 0.011 0.024 0.032 0.022 0.0110 014 0.262 1.01 0.14 0.017 0.021 0.018 0.024 0.0190 513 0.27 1.10 0.19 0.014 0.023 0.024 0.027 0.0196 116 0.26 1.00 0.14 0.013 0.027 0.024 0.016 0.0196 413 0.26 0.95 0.25 0.010 0.025 0.156 0.060 0.0104 118 0.25 0.18 0.023 0.070 0.024 0.012 0.0185 117 0.24 1.03 0.2 0.020 0.090 0.038 0.025 0.0091 114 0.26 0.89 0.15 0.012 0.125 0.048 0.032 0.0089 223 0.49 1.49 0.18 0.012 0.023 0.130 0.035 0.0146 324 0.49 1.44 0.18 0.013 0.026 0.124 0.054 0.0144 423 0.49 1.41 0.25 0.012 0.024 0.046 0.050 0.0121 021 0.39 0.82 0.15 0.023 0.025 0.012 0.022 0.0123 523 0.38 0.85 0.13 0.015 0.028 0.011 0.020 0.0115 0.39 0.80 0.15 0.023 0.028 0.015 0.013 0.0111 VII 213 0.12 0.54 0.10 0.012 0.024 0.020 0.044 0.0114 412 0.12 0.51 0.16 0.009 0.025 0.047 0.024 0.0128 313 0.12 0.46 0.26 0.012 0.022 0.110 0.045 0.0119 0.16 0.18 0.03 0.006 0.021 0.019 0.035 0.0107 211 0.19 0.22 0.02 0.012 0.024 0.014 0.044 0.0115 0.32 0.26 0.03 0.006 0.023 0.120 0.02 0.0190 013 0.21 0.76 0.19 0.022 0.022 0.035 0.006 0.0124 512 0.204 0.64 0.18 0.012 0.025 0.046 0.030 0.0114 113 0.21 0.54 0.17 0.022 0.022 0.017 0.013 0.0120 012 0.20 0.39 0.15 0.010 0.026 0.014 0.018 0.0107 311 0.19 0.33 0.18 0.008 0.028 0.048 0.048 0.0111 023 0.3 0.29 0.17 0.018 0.026 0.017 0.012 0.0059 ment electric furnace alloy steel the field the hearth. basic open- With the proper customer pres- sure developed, however, the open- hearth special steel producer was forced develop the necessary technique produce steels the characteristics demanded the user, with the result that are just emerging into new under- standing the possibilities the basic open-hearth furnace pro- ducer high-grade steel. One the reasons for keeping the part played aluminum more less secret was the old preju- dice against aluminum, due its use the past quiet “wild” heats, etc. There had also been 24—THE IRON AGE, October 10, circulated considerable publicity the disastrous effect visible alumina inclusions soundness, machineability and other require- ments for good steel. licity was, course, ascribed aluminum deoxidizer and was due primarily lack knowl- edge how heat steel should prepared before extremely active element such aluminum added. There little, any, evidence that the correct addition fair- large addition aluminum properly prepared heat will in- crease unsatisfactory extent the amount visible non-metallics. cannot denied that there some tendency increase the number inclusions rated oxides with increase alumi- num, but the effect the number so-called “slag” inclusions nil. The increase the oxide inclu- sion rating the worst small and affected other variables than aluminum, such tempera- ture, rate and extent deoxida- tion, ete. Epstein has stated that alumi- num either the ladle the mold does not necessarily result ting inclusion ratings against alu- minum additions, was found that the low aluminum heats killed with manganese and silicon were lowest oxide-type inclusions, while the low manganese, low silicon heats with aluminum were the highest, could expected. Aluminum Additions Investigated Much work has been done de- termine the balance between the condition the steel which the aluminum added, the timing the addition relation the time solidification, and the size the addition. This work, however, has been large scale, involving commercial heats, and the results have been more less empirical. the effort determine more accurately the effect aluminum additions plain carbon steel varying carbon and manganese contents, steel was made 300- Moore Electromelt furnace using the same base scrap every case well the came (pre- pared) slag. The total metallic charge used was cut from sheet bar, all from the same ingot low-carbon rimmed steel heat having anal- ysis 0.05 0.05 Mn, 0.04 Si, 0.010 0.030 0.040 0.019 Al, 0.010 0.05 Cu, 0.02 Ni, and 0.02 Cr. The steel was melted basic open-hearth furnace un- der finishing slag which analyzed 27.5 FeO, 10.2 10.6 9.8 31.8 CaO, 6.4 MgO, 2.0 1.68 and 0.13 Alumi- num addition ladle was oz. per gross ton, the heat rimmed well and nothing any way was u