The Iron Age 1939-04-06: Vol 143 Iss 14

FRITZ FRANK President P J. H. VAN DEVENTER Editor , Managing Editor News Editor Editor Emeritus Machinery Editor Art Editor Metallurgical Rditor Associate Editors Washington Editor Resident District Editors Pittsburgh Chicago Cleveland Detroit Editorial Correspondents London, England Cincinnatt ‘ Boston Hamburg, Germany i ¥ Milwaukee San Francisco Toronto, Ontario Birmingham Newark, N. J. St. Louis TURNER, Buffalo APRIL 1939 Little Business and the Wagner Act Owned and Published Colored Stainless Steel CHILTON COMPANY (Incorporated) Electric-Furnace Brazing Problems Publication Office Executive Offices Industrial Gas Sales Conference Philadelphia, Pa. New York, New Devices for Plant Service and Safety new FREDERIC STEVENS, Vice-President JOSEPH HILDRETH, Vice-President Rolling Properties Clad Steels GEORGE GRIFFITHS, EVERIT TERHUNE, Vice-President the Assembly Line WILLIAM BARBER, Treasurer JOHN VAN DEVENTER, JULIAN Washington News THOMAS KANE, CHARLES BAUR, Statistics Metal-Working Activity BAUR, General Advertising Manager Weekly Ingot Operating Rate H.. DIX, Manager Reader Service Rate Activity Capital Goods Member Associated Business Papers Indexed the Industrial Arts Index. Plant Expansion quipment uying 110 Published every Thursday. Subscrip- sessions, Mexico, Cuba, .00; Can- ada, $8.50; Foreign, $12.00 year. Single copy, 25 cents. Cable Address, Just Between Two 146 ADVERTISING STAFF Emerson Findley, 621 Union Cleveland Herman, Chilton Products Advertised 150 = K. Hottenstein, 802 Otis Bidg., Chicago in E. Leonard, 239 W. 39th St., New York Peirce Lewis, 7310 Woodward Ave., Detroit Index Ober, 239 39th St., New York W. B. Robinson 9 > Ids Box Hartford. Conn Copyright 1939 Chilton Company (Inc.) | | @ | ; land 4 ‘ a ‘ 30—THE IRON AGE, April 1939 THE TUNGSTEN MOLYBDENUM HIGH SPEED STEEL WITH HEAT TREATMENT SIMPLE entirely new steel, offering the user fine performance plus simple heat treatment favorable cost! D-B-L long-standing ideal metal-working men has been realized unique Tungsten, Molybdenum, Vanadium combination enabling out- standing economies many uses high-speed cutting steel one which can handled with the same equip- ment requiring speci furnaces coatings protect the steel. Another D-B-L advantage that lower temperature required harden it. Easily machined, easily forged, D-B-L possesses the significant properties high impact resistance, wide hardening and tempering range, high secondary hardness—together with fine, well-dis- tributed carbides. You know best what these qualities can mean your particular operations —how advantageous and profit-aiding! Try D-B-L your own work. Let Allegheny Ludlum metallurgists and en- gineers cooperate with you the appli- cation details, without obligation—and write the meantime for detailed “Blue ALLEGHENY “STEEL CORPORATION TOOL STEEL DIVISION WATERVLIET, YORK f & wil q j { THE IRON AGE ... APRIL 1939 ESTABLISHED Vol. 143, No. LITTLE BUSINESS AND THE WAGNER ACT long ago judge issued injunction against picketing the case small business concern. There were few people employed this concern, but these few had joined one the big unions and were therefore entitled for their dues money. However, the judge, who made plain that had nothing against unionism such, held that concern this small size was weak comparison with the strength the union that had chance whatever the case contro- versy. Now that was something that few people had considered. look upon legitimate unionism evening the odds for the small fry. Making possible, when necessary, for little Bill Jones, who just cog big corporation, "stand for his before the president, board directors, corporation lawyers and other brass hats. That, least, the theory. the American theory fair play. None likes see big fellow take advantage little one. was that theory that enabled the passing the Wagner Act. But did not consider the other side it. did not think the small employer who, with his limited resources, far more helpless when put upon the CIO the Labor Board than Bill Jones against his big employer. Just see how many these little employers there are who face such embarrass- ing predicaments, referred the Labor Information Bulletin, published the United States Department Labor. (Issue January, page Much our surprise from this that all the employers labor our country, exclusive railroads, farmers and non-profit public services, three-quarters them average nine fewer workers Every one these little business men who employ nine people less would find himself extremely unpleasant and vulnerable position if, perchance, incurred the wrath bushy browed John, were brought before Labor Board Court, backed Uncle Sam's billions. With his few dollars the bank, could not even afford hire good lawyer. After all said and done, the Wagner Act seems resemble the old-fashioned coal burning fire engine that did not have spark arrester. When went put out fire, usually started ten other fires along the way before getting there. | { ~ 4% | | ) 4 Are You Pegging for Bigger Profits You will want the greatest possible value for your dollars that into steel. You will want the right steel for each purpose. For example many manufacturers are now obtaining 25% more weight reduction without loss structural strength using Inland Hi-Steel. Others are adding 300% 500% longer life when exposed atmospheric corrosion using Inland Copper-Alloy which costs but little more per ton than ordinary steel. 32—THE IRON AGE, April 1939 Increasing numbers shops are using Inland Ledloy, the new lead-bearing steel—which permits 30% more than 100% increased machining speeds. you use sheets strip the right analysis combined with proper heat treatment, finish and uniformity will increase the speed your forming operations. Inland men will gladly check these economy possibilities with you. And their personal interest serving you may result some excellent methods lifting your product- appeal lowering your costs order peg profits higher during the PILING RAILS TRACK ACCESSORIES REINFORCING BARS ‘ | | d 3 | | ‘ | | | . VY 7 South Dearborn Street, CHICAGO District Offices: KANSAS CITY ST.LOUIS | | tenitic grain size absolutely value unless its effect upon the physical properties steel known and applied service, the fol- lowing paragraphs briefly summarize the influence grain size variations upon the physical properties and char- acteristics steels. These conclusions are based mainly upon published data and, although they show definite trends, they must judiciously evalu- ated since they are controlled largely the method deoxidation. Con- sequently, what applies killed steel (fully deoxidized) does not hold for unkilled rimming steel and vice Effect Grain Case Depth showed that (a) grained steels, carburizing steels, were more prone soft spots quenching than coarse grained steels, (b) grained material carburized less deeply than coarse grained, and grained material had dency warp than coarse grained steels due its non-uniform harden- ing. Epstein, Nead and Washburn’ also showed that the coarse grained steels carburized more deeply than fine grained steels (aluminum killed), and that the case depth was usually per cent greater. Swinden and Bolsover™ observed low carbon steels that only small difference ex- isted between the carburized cases fine and coarse grained steels, with the latter possessing slightly higher carbon penetration than the former (fine grain steels). carburized actions, E., Vol. 67, 1922, 341. burn, Transactions, M., Vol. XXII, 1934, Swinden and Bolsover, Jour- nal Iron and Steel Institute, 1936. knowledge the aus Carl Shapiro Consulting Engineer, New York HIS the third section three- part article, and deals with the effect the austenitic grain size upon the mechanical and physical proper- various methods which the aus- tenitic grain size determined, ap- peared the March 16, 1939, issue THE IRON AGE, and Part Il, de- scribing the factors which influence the austenitic grain size, appeared the March 30, 1939, issue. per cent nickel steels, they did not find any marked difference carbon penetration between the fine and coarse grained steels. further investigate the effect grain size upon case depth and char- acteristics, the writer carburized series coarse and fine grained (prior structure) nickel 2512), chrome-nickel (SAE 3312) and one per cent basic electric carbon tool After carburizing Ehn Test), the specimens in. long in. diameter) were tested for the percentage carbon present removing successive outside layers (0.003 in. radius) and testing for carbon the combustion method. The results the carbon determinations showed that the cases the coarse grained nickel chrome nickel steels were always slightly higher carbon concentration than the cases the fine grained steels. However, the per cent carbon steels, steels. carbon content between the fine and coarse grained steels was observed. note whether the carbon content the original uncarburized material influenced the case depth fine and coarse grained steels, series fine and coarse grained low, medium and high carbon steels, containing 0.10, 0.50 and per cent carbon respec- tively, were carburized hr. 1700 deg. and furnace cooled. The car- bon content the carburized steels showed that (a) the case the coarse grained low carbon steel (0.10 per cent carbon) possessed very much greater carbon concentration than the fine grained low carbon steel, (b) the coarse grained medium car- bon steel (0.50 per cent carbon) was slightly greater carbon concentra- tion than the fine grained steel, and (c) the carbon concentration the high carbon steel (1.0 per cent car bon) was practically the same. Since the original carbon content the material seemed influence the carbon penetration fine and coarse grained steels during carburization, another series the foregoing steels were carburized hr. 1700 deg. instead hr., note whether time temperature affected the trend the above results. The findings this portion the investigation not only confirmed the above results the low and medium carbon steels but intensified them. Moreover, high carbon steel, they showed that the carbon penetration the coarse grained steel became greater than the fine grained steel. Concluding the effect grain size upon the case depth carburized steels, may stated that (1) coarse grained steels will always carburize more deeply than fine grained steels THE IRON AGE, April | ‘ | BARS given sufficient time temperature, (2) the difference carbon concen- tration, after carburization, between coarse and fine grained specimens the same heat determined mainly the original carbon content the material and time temperature, and (3) this difference progressively de- creases with the original carbon con- tent the material. The Function Grain Size Upon the Rate Transformation: has been known for many years that the structural condition the material prior heating above the thermal critical influenced the alpha-gamma transformation range and temperature. However, where sufficient given complete solubility each definite temperature interval, ideal and equilibrium conditions, the varia- tion prior structure and grain size should not affect the characteristics and temperature range the al- pha-gamma transformation range and temperature. Davenport and showed that the normality the steel influences the transformation characteristics. Fig. reveals that abnormal fine grained steel possesses, during transformation, higher carbon diffusivity and trans- formation range than normal coarse grained steel. summary the entire situation adequately given who reviewed his work low and medium carbon steels follows: the rate which ferrite formed during the transformation gamma alpha iron proportional the grain area per unit volume and the specific reactivity the steel. Fine grained steels obviously trans- form more rapidly than coarse grained steel account the larger grain surface involved. However, both fine and coarse grained steels over- heated until they both have the same grain size, the steel which was orig- inally fine grained will still have higher transformation rate than the originally coarse grained steel. This higher transformation rate due the presence fine particles which act nuclei for fer- rite formation. this particular in- stance the specific reactivity not great factor rate transfor- mation grain size, but the effect nevertheless present and would un- doubtedly cause some variations Vol. XXIII, 1935, 113. Grossmann, Metal Progress, White and Clark, Trans- actions, M., Vol. 1934, 1069. 34—THE IRON AGE, April 1939 certain properties which depend the extent which the transformation occurs. This subject rate trans- formation and specific reactivity the utmost importance all heat treatments. hardened steels for example, the two factors, grain size and specific reactivity determine, for given quenching procedure, the depth hardening and properties the hardened piece.” Since the subject hardenability the heading the following topic and since mainly function transformation rates and grain size, these two factors will considered mum hardness order avoid any confusion, was pointed out illustrate this fact, Grossmann cited the case two steels: 0.70 per cent carbon steel and 0.35 per cent carbon steel, the former may when fully hardened attain hardness Rockwell 65, compared with only Rockwell for the latter, but the two steels may have the same hardenability; that is, they may require the same speed quenching bring their respective full hardness.” note the effect grain size variation upon hardenability, Daven- 1G. 10—Simultane- ous cooling curves for fine-grained ab- normal and coarse- grained normal steels similar composi- tion. (Davenport and together order obtain concise version their inter-relationship. The Effect Grain Size Upon Hardenability (Hardness and Pene- tration): This subject has held the spotlight since 1930 when Bain and his co-workers introduced the curve and the subject hardenability. Its importance has not been exaggerated many still believe but, fact, un- derestimated from the practical and theoretical considerations. However, since the subject “hardenability” the focus much investigation and publication, suffices this article only discuss the effect grain size upon hardness and depth penetra- tion. Before doing so, prime importance distinguish between hardenability and the potential maxi- port and Bain’ hardened and fractured series specimens from the same temperature after they were coarsened various degrees. The results they obtained are shown Fig. 11. These illustrations readily reveal the tremen- grain size upon the depth hardness many cases, such carbon and alloy structural steels, various in- vestigators report that the depth penetration between fine and coarse grained steels were approximately similar and that, general, the fine grained material had lower hardness than the coarse grained steel. Many test methods and procedures have been advanced determine hardenability but, date, the only | | — Q b * | 700 + >, Coarse 4 690 | 670 | % | Cooling Minutes | ' | | els ind ame ned they hese nen- nitic ness rbon in- yarse ately fine dures only reliable method used ascertain the complete depth hardness penetra- tion and hardness the acid etch method, which reveals the depth the case and core the hardened specimens, and hardness measurements (Rockwell, Vickers scratch methods), which indicates the hardening power the material. Since many factors influence the hardenability rating steel and since this discussion refers only the effect grain size variations upon hardenability, the author recommends the reading the 1938 publications the American Society for Metals bility the un- killed and aluminum- killed 0.39 per cent carbon steels Fig. 10, measured the martensite and fine pearlite disks quenched from 1600 deg. (Daven- port and Per Cent Martensite dealing with hardenability, present many new angles and infor- mation upon this pertinent subject which not within the scope this paper. Effect Grain Upon Tensile Properties: determine the effect grain size variation upon the ten- sile properties steel, Epstein, Nead upon specimens taken from the middle and bottom coarse and fine grained ingots. These results showed that after heat treatment, which produced difference grain size between and fine grained steels, the fine steels possess greater yield Strength, slightly higher ductility and approximately the Strength, White and Clark” performed short time tensile tests upon two molybde- num steels (0.50 and 0.25 plus 1.25 Mn) room and elevated temperatures 1400 deg. and concluded that (1) the grain size in- fluences the tensile properties room and elevated temperatures, (2) coarse grained steels possess greater tensile strength than fine grained material over major portion the tempera- tures studied, (3) the yield stress (stress which produces permanent deformation 0.2 per cent the gage length) the coarse grain man- ganese-molybdenum steel superior Per Cent Fine Killed Section the fine grained material over the greater portion the temperature range (up 1200 deg. F.) and then dips slightly below the fine grained steel; while the carbon-molybdenum steel, the fine grained material su- perior from deg. 900 deg. and above this temperature, the coarse grained steel possesses the higher value, (4) only slight variation exists between the proportional limit fine grained and coarse grained steels, and (5) the ductility (elonga- tion and reduction area) these two types steel show that, although practical difference exists between the fine and coarse grained steel room temperature, the fine grained steel superior the coarse grained material until certain range reached, approximately 900 1000 deg. F., and then the coarse grained material superior the fine. Swinden and also ex- amined the effects grain size upon the tensile properties open hearth steels and postulated that, general, the yield point and ultimate strength decreases with the finer grain size, while the elongation and reduc- tion area increase with the smaller grains. The above results seem indicate that, room temperature, the coarse grained material possesses less duc- tility than fine grained steels, but greater strength; while elevated temperatures, these characteristics may vary the different types steels. Effect Grain Size Upon Creep: the outstanding 1939 Howe Memo- rial Lecture, Dr. Gillett re- vealed the true lack knowledge that possess concerning the charac- teristics creep and the inference grain size. Dr. Gillett timely stressed, although much work has been done upon the various factors influencing creep, definite conclu- sion can drawn. may stated, however, was shown Dr. Gillett, that coarse grained steels, regard creep characteristics, are superior fine grained steels, elevated tem- peratures, and the resistance creep becomes less with finer grain size. The Effect Grain Size Upon Properties: Numerous investi- gations definitely showed that fine grained steels possess much higher impact value than coarse grained steels the same heat. This increase impact value seems vary with the different types steels and with the deoxidation process but, nevertheless, regardless the type steel and deoxidation method employed, fine grained steels seem possess greater impact value grained steels. The Effect Grain Size Upon Brittleness: After showing that fine austenitic grain size yields higher impact property than coarser grain, Swinden and Bolsover™ also investigated the effect grain size variation upon the temper brittle- ness steel. (Temper brittleness, well known, the name applied the loss ductility impact that results after tempering hardened specimen sub-critical temperature and slowly cooling. This loss im- pact not observed specimens quenched from the tempering tem- perature but only those which are slowly cooled.) Swinden and Bolsover THE IRON AGE, April 1939—35 | l- 4, 100 Hardenability TABLE Ill The Effect Deoxidation Aging Carbon Steel -Izod Impact—Foot Pounds Increase Hardness Per Cent Stee! After Quenching, Before After (Ft.-Lb.) Loss Rockwell Strain Aging Strain Aging During Agings 9.9 54.2 6.2 88.2 2 7.2 72.5 14.4 80.1 4.6 77.6 22.9 70.9 1.2 85.3 76.3 11.8 TABLE The Effect the Austenitic Grain Size Upon the Physical, Chemical and Structural Characteristics Steels Influence Grain Size Variation Upon: Remarks (1) Fine grained steels are prone to yield soft spots and ab- normality. (2) Fine grained steel carburizes less deeply than coarse grained steels. (3) For constant carburizing time and temperature, the per cent carbon impregnated less than coarse grained steels. Carburizing Characteristics Fine grained steels transform more rapidly and higher tem- Rate Transformation perature than coarse grained steels. Hardness Hardness with the increase grain size mild sheet steel. Fine grained steels harden less fully than coarse grained steels. general consensus Results are influenced the method deoxidation. However, it is generally upheld that fine grained steels possess better ductility than coarse grained possess slightly lower strength characteristics. Tensile Properties Coarse grained steels are more resistant creep than fine grained steels. Creep Impact Fine grained steels seem to possess greater impact values than coarse grained steels. Temper Brittleness (Impact) Resistance temper brittleness becomes greater with the finest grain size. Brittleness Sub-Zero Temperatures (Impact) Impact values fine grained steels are greater sub-zero tem- peratures than coarse grained steels. Hysteresis, residual and coercive force decrease with increasing Magnetic Chs eteristics A haracteristics grain size. Fine grained steels age less than coarse grained steels, depending primarily upon the type and method deoxidation. Aging dispute. Generally believed, however, that coarse grained steels Machineability A i are more easily machined than fine grained material. Constant deformation and temperature: Fine grain requires a shorter time and temperature. Constant deformation and time: Fine grains recrystallizes lower temperature. Constant time and temperature: Fine grained steels recrystallize much faster than coarse grained steels for the amount reduction. Reerystallization Decarburization Fine grained steels decarburize less than coarse grained steels. Piping Fine grained pipe more deeply than coarse grained steels. Fine grained steels are superior coarse grained steels since they Stamping result smoother finished surface condition. Tempering: Fine grained steels respond to tempering much faster than coarse grained steels. Annealing: The finer the grain size, the shorter becomes the an- nealing time. Solubility: Fine grained material goes into solid solution much faster than coarse grained material. Agglomeration (aging): Fine grained material agglomerates more quickly than coarse grained material either tem- celerated Heat Tredtment Colorimetric Compari-on Tests: Fine grained steels dissolve more rapidly than coarse grained steels and indicated lower calculated percentave of element present, e.g., color carbon tests. Volumetric-titrational Test: Fine grained steels yield greater percentage element after titrating than coarse grained steels, nitrogen test. Chemica! Test 36—THE IRON AGE, April 1939 noted after tempering hardened coarse and fine grained steels that the coarse grained material was less susceptible temper brittleness than the fine material, although the impact resistance the fine was greater than the coarser aggre- gate. who also determined the effect tempering upon two medium carbon steels, showed that for identi- cal hardness, the Izod values the grained steels were approximately six times greater than that the coarse grained, after quenching and tempering. However, did not as- certain the effect grain size upon temper brittleness, was done Swinden and Bolsover. White and also tested coarse grained steels the various tempering temperatures 1200 deg. and showed that fine grained steels possess the maximum impact resistance over the major portion the temperatures examined, This was true whether the specimens were held 1000 hr. temperature. From the above results, may stated that the fine grained steel possesses greater impact sistance than coarse grained steel, al- though the latter less susceptible temper brittleness than the fine grain aggregates. Influence Grain Size Upon Brit- tleness Sub-Zero Temperature: determine the effect austenite grain size variations upon the sistance Herty” tested four series made different methods deoxida- tion (method deoxidation reported under the effect grain size upon aging) means the Charpy Im- pact Test (Izod notch) deg. and minus deg. found that the loss impact resistance was more marked the coarse grained steels than the fine grained aggregates. The loss impact resistance de- creased progressively from per cent the coarse grained steels, which contained the greatest amount dis- solved oxygen, per cent the fine grained steels which contained the least amount oxygen. Influence Grain Size Upon Aging: illustrate the effect grain size and deoxidation upon the aging char- acteristics various steels, Herty” M., Vol. XXII, 1934, 1017. Rowland and Upthegrove, Transactions, M., Vol. XXIII, 1935, 187. M., Vol. XXII, 1934, 926. Vol. 1934, 1099. Vol. XXII, 1934, 1142. s § q quenched series four steels and aged them room temperature for two weeks. also determined the characteristics these steels after they were compressed per cent, heated for 450 deg. (842 deg. F.), and then aged them room temperature for one day. Before and after each aging treatment, tests were made. The results these treat ments are summarized Table The steels listed Table were manganese; steel No. silicon- killed steel deoxidized with manganese and silicon; steel No. semi-killed steel deoxidized with manganese and minum the ladle; and steel No. dead-killed steel strongly deoxidized with silicon-manganese followed de- oxidation with excess aluminum. The dissolved oxygen content and the austenitic grain size these four steels progressively steel No. steel No. that the change after quenching, the greatest the steel which gave the greatest loss impact value (88.2 per cent) after strain ing and that the data every wa) consistent with respect these two properties (hardness increase and loss impact). The results the work Swinden and Bolsover™ upon the effect grain size upon the aging characteristics based upon tensile and specimens quenched from below and above the thermal critical range and aged room temperature, showed that (a) the hardness increase was and coarse grained material upon ag- ing, (b) the increase maximum tensile strength was the same pro- portion the fine and coarse grained steels, (c) the yield point the grained more rapidly days’ aging than the fine grained material, the decreases the reduction area and elongation were practically the same ratio, and finally (e) the Izod impact value the coarse grained while the fine grained material slightly. The above investigators also strained material (15 per cent) and noted that after cold working and tempering 250 deg. (842 deg. aging room temperature for approximately four months, that the coarser grained material yielded greater loss toughness than the fine grained material when subjected the same degree cold working and aging. These results, supplementing Herty’s, indicate that the degree and method deoxidation influence the aging characteristics, inasmuch the meth- deoxidation influences the amount oxygen retained solid solution the material, which turn will regulate the aging properties and grained material. From these deduc tions, seems logical assume that the aging carbon steels acceler- ated the oxygen present solution the material. This assumption further substantiated observation (e) inthe foregoing paragraph, which shows that the loss impact coarse grained steels may attributed precipitation that taking place dur- ing aging, while the fine grained steels very little precipitation occurs. Effect Grain Size Decar grain size and its influence upon the surface decarburization was made Rowland and They found that the rate decarburization varied with grain size and that the coarse grained steels possess greater decarburizing tendency than the fine grained material. also studied the effect time and temperature the character and width the total decarburized zone for fine and coarse grained steels and revealed that (1) the relative widths bands coarse and fine grained steels independent the time the decarburization tem perature, and (2) the maximum width the ferrite bands both fine and coarse grained steels takes place when decarburization occurs approxi mately the transformation range. Grain Versus Machineability: The effect grain size upon the chineability steel has not received much attention, although McQuaid states that metal removed more freely from coarse grained steels than from finer grained material, but the latter gives smoother finish surface. Others reported that after quenching and tempering, metal may removed more rapidly from fine grained steels. Swinden and Bolsover™, numerous machining tests, failed observe any difference between the machining grained steels. also came the same conclusion Swinden and Bolsover after studying the machine- ability Bessemer screw stock. Thus, from these investigations, definite conclusion can obtained until fur- analysis. Effect Grain Upon Piping: Epstein, Nead and showed that fine grained steels tend more deeply piped than normal commercial steels, since they require amount silicon and aluminum refine them. Moreover, they showed that fine grained material produces lower percentage yield than ordinary commercial steels, since more ping necessary remove the deeper pipe. They also claim that economy may achieved casting fine grained steel into ingots the use hot tops. Effect Grain Sise Upon Deep Drawing Characteristics: Kenyon™ brilliant paper upon the effect grain size upon the deep drawing re- vealed that surface smoothness function grain size. showed that the finished surface conditions line grained mild sheet steels were much superior those steels since the latter became rough after deep drawing whereas the fine grained steel remained smooth and uniform. Grain Upon Mag- netic Properties: Ruder™ correlated the existing data the effect grain size upon the magnetic properties steel and then that the hys- teresis, coercive force all decrease with increasing grain size. This condition varies with the prior treatments whether mechanical chemical and, consequently, the effect grain size cannot readily ascertained unless complete series tests are run, was done Dr. Ruder. Summary Since the scope this paper, which appeared three sections, was present concise version grain size, Table briefly the effect grain size upon some the physical, chemical and structural properties and characteristics steel. The results are variable since, has been repeatedly stated, they are influenced the melting procedure, method deoxidation, casting tem- peratures, soaking temperatures, and prior mechanical and ments. Acknowledgment The author wishes express his sincere appreciation Mr. Schempp, metallurgist the Crucible Steel Co. America for his many conversations and valuable discussions during the course this survey. THE IRON AGE, April - | | | | 4 | 4 q q » q q 4 > > q > 4 4 4 q Colored Black, Gray and Red Oscar Bach coloring stainless steel's contradiction Easy, but difficult; mo- mentous, but trivial; much talked about, but nurtured secretly—time only will de- cide the when, the how and the how much. ° ° ° this perispherical and trylonic age, it’s supine metal manu- facturer who damn well doesn’t realize that his particular product engaged cut-throat competitive battle. Only one rule recognized, and that’s “devil take the The battlecry exploit and defend existing outlets, all the while experi- menting, diversifying and propagan- dizing constantly encroach out- lets dominated other metals. Stainless steel, much may pro- fess hold aloof from the common battle, all the same quite familiar figure the competitive struggle. It’s true, course, that competitive blows handed out stainless frequently lack decisive wrist-snap, but such spirit but more reflection general ° LIPPERT Metallurgical Editor, The Iron Age ° ° weariness and lack cooperative ef- fort traceable occasion flurry intra-mural gouging. If, for any competitive application, strength low cost specified, then ratio, then stainless frequently can slug its way front for some considera- tion. resistance corrosion, par- ticularly severe diversified corro- sion, the desideratum, then almost inevitably stainless alloys occupy the van the battle metals. Such the competitive functional position stainless alloys today. But even beyond this, snap judgment would addition credit stainless with aesthetic advantages. The alloys take polish mirror brilliance, which seemingly immediately creates sizable outlets purely decorative nature, outlets requiring addition decoration measure corrosion re- sistance. But note well that this brilli- ant finish, just like many other things this mad world, far from being unmixed blessing. Stainless steel with unfortunate pro- ficiency picks disfiguring finger- marks and greasy films, and decora- tive applications the visible record day-to-day vicissitudes can al- mightily discouraging. And the bril- liant finish, spectacular often moderate doses, can used large amounts ill-advisedly give stain- less’ most férvent partisan the willies. sure, there’s denying lim- ited aesthetic usage, what with the Empire State and Chrysler buildings sheathed stainless and every house- hold stocked with stainless appliances and knick-knacks, ofttimes all too many knick-knacks. But such applications corrosion resistance plays much more important role than appear- ance the selection the material. titivate the frequently unpre- possessing exterior stainless has been the object diverse amount effort during the past few These artifices are themselves admission aesthetic limitations, proof the cognizance some pro- ducers that only foot the door outlets that conceivably might account eventually for sizable ton- nages worthwhile prices. Quite early the game buffing was varied furnish surfaces ranging from grayish satin (No. bright mirror-like (No. finish. later date surfaces were pebbled THE IRON AGE, April A 2 4 Lit q 4 similarly roughened tone down brightness and reduce the visibility the Arduro process the United States Plywood Co. (work done Regal Art Glass Co., New York) blast fine silica employed tain degree shading due the depth cutting. Chemical darkening also has been used vary the reflec- tivity stainless, and, more recently, elaborate practices have create surface decoration, trasts, for instance the etching and rolling-in designs, such exploited Sharon Steel Corp., stripes and patterns the prefinished material Acme Steel Co. color contrasts high tempera- tures have occasion been used fuse enamel onto the metal; non- ferrous metals are used sometimes appliques contrasting designs the decorative arts; liven installation there has been occasional use ordinary paint and lacquer, quite evident that the efficacy these practices most limited. The former dealing only with shadings bright and dark not even touch the real problem; and the latter are obvious stop-gaps employed merely for want something better. High tempera- ture enameling course commer- cially impractical, and painting and lacquering are subject discolora- tion, peeling and disintegration. And, there little promise electrolytic coloring, such the Electrocolor technique United Chromium, Inc. which even though beau- tiful coloration any shade any metal has nonetheless little sistance and requires overcoat clear lacquer protect the colored film from exposure and handling. straightforward attack would course involve coloring the stain- less steel itself. Such coloring pro- cess. for maximum commercial ex- ploitation, must needs quer, and wide chromatic range. more important, the color should certainly integral with surface and have deleterious effect the corrosion-resistant character- istics the stainless alloys. Various schemes coloring stain- less have been and are cosseted sev- eral members the industry, the tune considerable money ergy. Nonetheless, stainless producers group are emotionally divided into two schools thought. far the ma- jority hew cold skepticism, and privately level numerous strictures against coloring stainless gen- 40—THE IRON AGE, April 1939 eral. The contention that such col- oring technically impractical and prone blanket out the very es- sence the steel, the familiar intrinsicality identity the metal, what have Even gracious intervals, this group admits only that such integral coloring perfected and exploited would interesting merely specialty enterprise and would involve only volume The other, admittedly smaller group takes the other extreme, course. The prophesy that coloring would not only impart stainless the ulti- mate versatility, but would immedi ately and progressively favor pro with commensurate unguency rather sore profit state ments. The writer, with conventional edi undramatic midway position. believed that dependable coloring tech- nique can well highly the stainless steel knowledging course all times that stainless’ primary role functionally that structural strength ations, that coloring, being quite secondary. But, secondary role not neces sarily insignificant this instance, can assume considerable sizable demand already exists for stainless steel, and even sketchy market survey brings light numerous unsuspected, tonnage, applications such diver- potential outlet. coloring need not merchandized solely for its aesthetic appeal; quiries have appeared stressing only identification and surface protection. Conditioned Market Exists Architects are most vocal de- manding colored stainless steel, par- ticularly Government architects who have seen the colored stainless exhibit (prepared Oscar Bach) Procurement Division Washington. Bright metal’s use architecture limited, which limitation would dis- appear with the availability color. architecture aluminum has ticularly spectacular competitive edge stainless, primarily because Alumi- liting makes available any color the architect might specify. typical re- cent instance stainless’ vulnerabil- ity the Los Angeles Federal build- ing, which would have used tons colored (gray) stainless for span drels and exterior trim, for toilet stalls the colored eliminate finger marking. The former project went aluminum, and the latter was finally made painted steel, both because inabil- itv secure colored stainless. These two are just random examples; there have been many such projects. more than likely immedi- ate potential architectural out- let thousand more tons stainless exists, satisfied just soon coloring becomes commer- cially practicable. For purely decorative applications, mostly interiors, the fully insistent, although the ton nages involved are perhaps not vidually large. The new stainless steel trains use colored aluminum painted steel for interiors, outlet which would competitive reach colored stainless. Naval vate ship interest both are constantly terior trim, and other sibilities range from the simplest trim decorated the mod- ern manner vaults banks. Re- garding the latter, large-New York bank recently specified less for vault, but finally used gine-turned steel with clear lacquer, only later have spots. rust Miscellaneous applications, ately available colored are quite numerous number estingly diverse Certain stove companies desire less for trim, and one large maker electric stoves wants use black color the inside stainless shells holding heating elements order prevent unsightly heat cut down squawks from finicky house- wives. One large maker would like use mounting plates insure good pearance and permanent ance. Such plates now are made ordinary steel plated sprayed. Still another radio maker desires thin stain- struct the entire body smaller models, such shells backed with sound-proofing material and dec- orated the outside with permanent colors. Several furniture makers are asking for colored stainless incor- porate into new designs, and large maker pen points desires gold color for stainless steel points which will stand under the relatively severe corrosive attack ink. maker industrial controls would like finish stainless a ‘ : . | q operated push buttons red and black, take the place painted buttons now used and which are short lived due abrasion and corrosion from oils and chemicals carried workers’ hands. All these possibilities are merely cross-section large potential mar- ket for colored stainless, market which certainly also plumbing industry, cooking utensils, decorative arts, etc. The outlets are there tap immediately, but the color- ing process for stainless which will the tapping must comparatively cheap, fool-proof, way impair the natural corrosion resistance the stainless, and have wide chromatic ver- satility. seems well within reason that admitting coloring procedure such caliber, annual stainless outlets opened should aggregate two three thousand tons more, with future growth dependent only the ingenu- ity commercial designers and archi- tects. course obvious that most the outlets for colored stainless men- tioned herein are already serviced colored aluminum, painted lacquered common steel, steel protected electrocoatings. Furthermore, apparent that most the applica- tions the result desired not only col- oring but the same time high degree corrosion resistance. fact, the borderline between coloring and protection not bit well de- fined, but must assumed that col- oring must never performed the expense corrosion resistance, and the corrosion resistance must all times quite high. Stainless steel, being itself corro- sion resistant, serves the best pos- sible base carry colored surface, and, the latter has deleterious effect the resistant properties, the colored material should stand in- definitely all applications. How- ever, has occasion been con- tended that the typical stainless steel surface going blanked out using color, much money can saved any particular installation merely using ordinary carbon steel protected the surface with col- ored lacquer paint having high degree corrosion resistance. Such viewpoint presupposes that ordinary steel protected coating stable lacquer paint will stand equally well stainless, either uncoated covered with similar lacquer paint. There have been certain tests showing such the case, but the bulk experimental work indicates that the base metal itself resistant far longer life may expected under most corrod- ing conditions than for plain steel with surface protection lacquer. investigate this problem, one large company recently prepared or- dinary automobile steel panels and stainless steel (0.10 18.38 Cr, 8.97 Ni, 0.63 Mn, 0.68 Si, 1.16 Co) panels coating them all with coat lacquer followed cover coat black air-drying lacquer high corrosion resistance, similar the lacquer used the inside beer cans. All the panels were then ex- ject corrosive conditions, whereas the 18-8 steel similarly coated stands indefinitely. The foregoing judged show- ing that attractive market exists for colored stainless steel, market which currently competitively the hands Alumilited aluminum, painted, lacquered electroplated carbon steel. Furthermore, has been shown that carbon steel painted lacquered frequently breaks down under corrosive conditions, against the permanency coated stainless steel, stainless colored such ARGE stainless fountain for Skinner Silk Co., which will seen the building Man, His Wear, His Sports, the World's Fair. The figures around the base, designating the four seasons, represent feminine beauty, and will colored gold the Bach process. Four other colors will serve trim, and the fountain natural stainless the form lotus flower, highly stylized. posed for three months per cent sodium chloride spray atmos- phere, and similar set totally im- mersed 0.5 per cent ferric chloride solution containing per cent sodium chloride, which solution generally used for accelerated pitting stain- less steel. the per cent salt spray atmos- phere, the lacquered after three months exhibited no- ticeable change the coating, whereas the standard automobile blistered badly during the same time interval. The coating the automo- bile body steel failed completely after only one month’s immersion the ferric chloride-sodium tion, whereas the stainless similarly coated stood for the three-month period, there being blisters the coating. There was, however, some discoloration ferrous hydroxide, but removing this the coating ex- hibited its original luster. was indi- cated, therefore, that the coatings were not sufficiently impervious moisture protect plain carbon steel when sub- manner that -inherent corrosion resist- ance not impaired. Carbon steel electroplated with number differ- ent types attractive and corrosion resistant metals course would al- ways partly competitive, particu- larly when colored chromium platings now being developed come onto the market. But even such coatings are subject the ills plated metals base metal highly vulnerable corrosion, breaks the protective coating can result and rapid breakdown the composite. Thus with the market and advan- tages colored stainless steel estab- lished, the problem becomes one how stainless can colored, what work has been done such direction and what the present status the problem. Heat Tinting Investigated One the earliest patents the writer can find dealing with the col- oration stainless that issued Colin Fink and assigned the Alle- gheny Steel Co. Apparently nothing THE IRON AGE, April 4 . q has been done with this process. The patent, No. 1,893,821, Jan. 10, 1933, describes the use mixture sul- phuric and chromic acids form surface mordant, subsequently immersed dye form lake. Englishman, Hadfield, also has pat- ent dealing with passivating which mentions that under certain conditions color obtained. Still another patent mentions the use hydro- acid and certain metallic salts color stainless, and there are vari- ous other patents which way touch tentatively the coloration chromium and chromium-nickel steels. However, duplication the condi- tions mentioned certain the later patents has failed produce satisfac- tory color, some instances any color all. Another patent covers the flashing electrocoat cop- per onto any steel, stainless included, and subsequent heat coloring the copper. This procedure gives really beautiful and rich colors, even the most delicate pastel shades. But un- fortunately the not satisfactory and the film must protected with clear lacquer. And since colored lacquers will stand long clear lacquer, the colored lacquer might just well used the first place. Another interesting patent color- ing procedure just about what would expected, series claims the heat tinting stainless rustless alloys. The patent, No. 1,977,270 was issued 1934 Alexander Feild, who also perfected the unique pro- duction metallurgy employed Rust- less Iron Corp. The patent describes the pickling clean any the straight-Cr Cr-Ni rustless alloys, and heating the surface tints color of, say, old gold. Such coloration progressively passes through the various straw, dark straw, yellowish-brown, red-brown, deep purple, violet, blue and green, the steel gradu- ally heated, the color band ranging from light straw yellowish-brown being broadened out longer than the other colors. re- gards the temperatures required, the old gold color can secured when the surface reaches temperature about 600 deg. F., although the ap- the desired heat tint de- pends upon number variable fac- tors, such the size the article being treated, the temperature the agents imparting heat the article, the velocity and composition the gases surrounding the article during the heating period and the length time that the article subjected the 42—THE IRON AGE, April 1939 CORROSION TESTS TEST Resistance Colored (Bachite) and Untreated and Cr-Ni Alloys Test Specimens Hours Observations After Hours Hours 100 Hours PER CENT BRINE SOLUTION corroded formed effect effect surface corroded pitting continued effect effect effect effect badly corroded slightly corroded rust on edges two pits formed effect effect very badly corroded corroded rust edges few small swellings effect effect PER CENT FERRIC CHLORIDE AND PER CENT BRINE SOLUTION and 8...... one pit 18-8, Colored..... effect CONTACT CORROSION PER CENT FERRIC CHLORIDE AND PER corroded pitting continued three pits effect effect effect SOLUTION badly corroded badly pitted three pits effect effect effect Test Specimens Observations After Hours badly very badly very badly very badly corroded, corroded, corroded, corroded, solution solution green solution green solution green turned green deep pits deep pits, pitted, badly pitted, solution green solution green solution green pits forming pitted, pitted, badly pitted, solution green solution green solution green Cr, Colored...... effect effect, effect, few small solution solution pits, solution unchanged unchanged Cr, Colored..... effect effect, effect, effect, solution solution unchanged unchanged unchanged 18-8, Colored....... effect effect, effect, effect, solution solution solution unchanged unchanged unchanged very badly corroded very badly pitted three pits many swellings two swellings effect CENT BRINE 100 Hours very badly corroded, solution green very badly pitted, solution green badly pitted, solution green small solution unchanged few small pits, solution unchanged small pits edges, solution unchanged All specimens in. wide, in. long and in. thick. Analysis 6-Cr alloy 0.07 0.42 0.018 0.016 0.34 Si, 5.63 Cr, 0.52 and nickel. 0.019 0.021 0.33 Si, 18.42 Cr, mo