The Iron Age 1943-02-04: Vol 151 Iss 5

ace. selling Mich., 0.70 per cated 49) ovr =: LEWIS FOUNDE DIVI BURGH, PA. 1943 omestie naxima Cold 7 d and i J Machine Accuracy Compensates for Inexperience QUARTER century ago, during the first world war, many women took the places men turret lathes. Then, Warner Swasey employed scores women turret lathe operators. England, thousands women worked machine tools since the start the war. Now, America, more and more men are called into armed services, women are again taking places the ranks machine tool operators. Under supervision and with aid chucking heavy parts, women are capable producing good work Warner Swasey Turret Lathes. The capacity and greater accuracy built into modern Warner Swaseys compensate large extent for inexperience and lack finished mechanical Controls conveniently located and much the turning job automatic. Women can not expected fill the shoes expert machinists, but for the repetitive operations required produce vital production, women can trained quickly Warner Swaseys with surprising speed and You CAN TURN BETTER. FOR WITH WARNER SWASEY y © took scores have more their are fully extra trols for the vital FEBRUARY 1943 NO. VAN DEVENTER President and Editor BAUR Vice-President and General Manager fe) ° Managing Editor, LIPPERT News Markets Editor, ROWAN Technical Editor, OLIVER Associate News Editor JAMES Associate Editors Art Editor, WINTERS Editorial Assistants BUTTERS Resident District Editors Washington Pittsburgh Washington Cleveland Detroit OSGOOD MURDOCK Son Francisco Editorial Correspondents Buffalo Cincinnati FRAZAR RAYMOND KAY Boston Los Angeles HUGH SHARP JOHN McCUNE Milwaukee Birmingham SANDERSON ROY EDMONDS Toronto, Ontario St. Louis BACON Seattle ° ° DIX, Manager, Reader Service ° ° ° Advertising Robert Blair, Union Cleveland Herman, ‘Chilton Bld Philadelphia Raymond Kay, 2420 Ave., Los Angeles, Cal. Leonard, 100 East 42nd St. Peirce Lewis, 7310 Woodward Ober, 100 East 42nd New York Johnson, Market Research Mgr. Hayes, Production Manager. Baur, Typography and Layout. New York Detroit ° ° Member, Audit Bureau Circulations Associated Business Papers Indexed the Industrial Arts lished every Thursday. Subscription Price North America, South America and $8; Foreign, $15 year. Single copy, cents, Annual Number, $2. ° ° Owned and Published CHILTON COMPANY (Incorporated) Executive Editorial and Offices Advertising Offices Chestnut and Sts. 100 East 42nd St. Philadelphia, Pa. New York, U.S.A. OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH, GEORGE GRIFFITHS, EVERIT TERHUNE, VAN DEVENTER, Vice-President BAUR, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY DUFFY Vice-President Vice-President Vice-President CHARLES HEALE Editorial The Common Denominator Technical Articles Glass Gages Boron Steel Increasingly Martempering Quick Healing Burn Carburizing and Decarburizing Automatic Press Hard Chrome Plating New Equipment: Machine Tools Features Assembly Line Washington West Coast Fatigue Cracks Dear Editor News and Markets This Industrial Week News Industry Personals and Machine Tool Activity Non-Ferrous Metals Scrap Markets Iron and Steel Scrap Prices Comparison Prices Finished Steel Prices Index Advertisers Copyright, 1943, by Chilton Company (!ne.) 130 132 134 136 138 140 142 219 Fe 5 | 4 f ' | ov 4 | 1 } H | 4 7 . j | Base for Multiple Spindle Drill for Drilling Rifle Barrels order meet vital war production schedules time, machine tool manufacturers must sure getting the Machine Bases and Frames they need— when they need them. ever-increasing numbers, there- fore, they are buying bases built Mahon. Years specialized experience producing intricate designs and unusual sizes and shapes—plus as- surance delivery promised—has established the Mahon organiza- tion exceptionally depend- able source supply. Your blueprints will receive our immediate attention. Quotations will sent you without delay. THE MAHON COMPANY DETROIT CHICAGO 32—THE IRON AGE, February 1943 THE The Common Denominator arithmetic, many problems are solved finding common denom- inator among group groups assorted numbers. War global scale does that very same thing except that the assorted groups are people and not digits. The common denominator war the arrival the nations involved common purpose. And that means the cancelling out indi- vidual differences opinion and the conflicts thought and action that detract from the common purpose victory. nation can hope victorious war unless that common denominator found. And various nations about finding various ways. These ways are different day night. The Axis nations achieve it, under their fascistic philosophy, com- pulsion. Germany has done via the goosestep, Japan through indoc- trination the god-emperor phantasy, Italy through the bull calf bellow- ing megalomanic two-spot appropriately called the “duce.” democratic countries where centralization power has been avoided through national policy, the job harder. Yet can done. Witness China. China, today, probably the most united nation all the united nations. Yet before was attacked the men” was probably the most disunited and with the least powerful central government. Its gigantic area was divided into sections and provinces with constantly shifting political boundary lines, variously controlled conservatives, communists, bandit chiefs and what have you. greater variety aims, purposes, interests and ideas and greater differences ways achieving them ever existed anywhere earth. Yet today bandits and mandarins, peasants, paupers and merchant princes, communists and conservatives are working and fighting side side with one com- mon purpose. FEBRUARY 1943 China has found its common denominator. not likely lose after the war, once having found it. think that there powerful object lesson this for the United States America. too must find our common denominator not only order win the war but win the peace follow. Surely China with its vastly greater differences sectional and class interests and social strata can it, can too. Today our chief remaining problem find the common denomin- ator for capital, represented management, and labor. They have much more between them common interest than they have opposite purposes that this should not insuperable. Unfortunately these differ- ences have been and are magnified out all proportion because the selfish interests reactionary employers, self seeking labor leaders and vote seeking politicians. War has already done much iron out these differences. But expect war all. job which every right thinker should put his shoulder now, for the sake the America tomorrow. + ' | | | | | | ° ° | | | | > | | | | | | | | 7 “Scrap” orders Frank Baker, general purchasing agent Pullman-Standard Co., on his tour with L. C. Reed, chairman of the Chicago district dormant scrap campaign. Mark President long this war lasts the problem scrap supply will confront America’s steel mills. That why are again appealing you presidents manufacturing companies use all your influence and all your official authority move the dormant and potential scrap that remains about your plants. Yes, know you have had scrap drives, that you have had diligent scrap committees work for months. They have done fine job. But after all said and done their authority limited. Many the things that can and should marked scrap, under today’s standards Dearborn Street, Chicago > XP 3 W 3 SSN and necessities, are the very things which you, other officials, may have designated only few years ago “standby,” “reserve.” Maybe releasing some this potential scrap matter capital ac- count. any event will require your countermand old instructions, and orders from you establish new company policies, that surplus and unneeded machinery, spare parts, processed parts, etc., will reach steel mills vitally needed scrap. The next move yours, Mr. President mark today our fighters will have the the planes and the tanks they need win. lo | t scrap camper Sponsored Ordnance Department work here. Based six months’ experi- ence with such gages, predicted that eventually per cent more all fixed steel gages used ord- nance work will replaced glass gages. New possibilities for the application these gages are opening that the ultimate ex- tension may much more than per cent. The glass gage movement was fathered Lt.-Col. Stone, recently charge the gage lab- oratory and now executive officer the Frankford Arsenal. his opinion, glass gages have demon- the following advantages over gages made from tool steel: The thermal conductivity glass less than steel; therefore, heat transfer from the hands the inspector will not nearly great for steel and the ef- fect the gage dimensions ap- preciably less. Glass, because its relative fragility, will teach have respect for their handling. fact, obser- vation the careless manner which inspectors handled gages was partly responsible for the initiation the present glass program. nection with other physical prop- Long the vanguard technical developments relat- ing inspection gages, the Ordnance Department supplying the driving force behind the new program for substituting fiixed gages made glass for those made critical tool steel. The accompanying data and illus- trations were supplied through the courtesy Lt.-Col. Stone the Frankford Arsenal and Thompson the Corning Glass Works, Corning, OLIVER Technical Editor, AGE erties considered detail later. glass gage, the floor, either survives di- smashed smithereens. steel gage, strikes vital spot, may sprung out size and thus unwittingly allowed pass defective work thereafter. This very important point the mind Colonel Stone. assures that only accurate gages will remain service. When the component very near the size the gage, there less tendency for the compon- ent seize gall around the gage. This noticeable when steel plug gage near the “Not Go” end the size limit. fact, glass has some anti-friction properties that makes easier for plug. for example, enter hole and has speeded gaging much per cent. You get sense with glass plug gage that greatly accelerates the fac- holes. Often the “Not Go” end does not have used. Glass subject scratch- ing, but scratches glass not raise any burrs and thus change the effective size the gage occurs steel gages. glass plug gage with badly edges will still function 100 per cent checking instrument. (Design modifications are now being made offset the tendency chip.) Perspiration the hands inspectors has corrosive effect glass gages. Rust has ruined many steel gage storage and shipment, and juice from orange eaten the inspection bench lunch time has ally etched steel gages beyond re- pair. Glass appears have abra- sion resisting qualities equal better than steel many gag- ing applications. (See tests be- Glass gages are considerably less expensive and require less THE IRON AGE, February 4 : 5 ¥ 4 Bey, ° ° ° af me : ° ° ° ing | ac- ded 3 Li operator and machine hours produce. techniques point further re- duction finishing time and hence costs, particularly where large quantities gages are in- volved and mass production meth- ods can applied the glass manufacturing plant. Most important this time the saving tool steel for other uses. Vital machine tool capacity also released for other work. 10. Glass gages are easier handle inasmuch they are lighter than steel. 11. Glass gages afford visabil- 2—A pair and Go" plug gages made glass for the Frankford Arsenal. Markings are put acid etching. also possible photograph markings the gage the silk screen process. proposed that the end given red tinge. ity inspection which not al- ways possible with steel. 12. Many greasings and de- greasings are eliminated the process taking gages ovt temporary storage, checking them the laboratory, them the contracting plant and vice versa. Primarily this arsenal problem and encompasses also the problem permanent storage gages after the war. (See also paragraph 6.) The advantage low thermal conductivity put the head the list because was the realiza- 36—THE IRON AGE, February 1943 tion the potential possibility dimensional change steel gages due transference body heat that caused Colonel Stone order the first glass gage. Colonel Stone does not claim the originator glass gages, but resporsible for having introduced glass ordnance manufacture last sum- mer. The first glass gage was ring type, Fig. made measure the brass component which had number small teeth the peri- phery. These teeth been scratching and rapidly wearing steel ring gages. The glass substi- tute gage when last heard from had checked thousands these brass parts without showing any appreci- able signs wear. was made out hard flint glass glass nov- elty manufacturer, Heisey Co., Newark, Ohio. The hexagonal perimeter the gage takes its form from glass candlestick base. The gaging bore was ground out heavy duty lathe, using Dumore tool post grinder the compound rest. Later the bore was carefully lapped size. Despite the impro- vised set-up, the gage was made few hours and checked within Electrolimit comparator. would have taken few months get de- livery steel gage. This gage was taken around numver ordnance contracting plants several Ordnance Districts and put the inspection lines. Some scratching the bore took place, but was not nearly se- vere the corresponding steel ring gages. Thousands pieces were checked without able wear the glass gage. This convinced Colonel Stone the feasibility glass gages and launched the present program with the encouragement Col. John Rose, commanding officer Frank- ABOVE first glass gage used for Ordnance inspection was plain ring gage made from the base flint glass candlestick. The brass component shown the bore. ford Arsenal; and Col. Harry Hambleton, Col. Allen Lenk and Lt. Col. William Darmody, Office the Chief Ordnance. Much the detailed work has been carried Lt. Franklin Smith and Ben- jamin Patton the Frankford Arsenal gage laboratory. the project stands the be- ginning 1943, the following types gages are made available glass: Plug gages, in. diameter and over Plain “Go” and “Not Go.” Double end plain plug. ( \ a glass rry and Office ‘uch Ben- nkford the be- types lable eter and Go.” Ring Plain “Go” and “Not Go.” Twin rings. Combination ring and snap. Certain types snap gages Profile and position gages Certain types flush pin gages with pin size in. and over (Yet tried out) Chamber for measuring the entire profile complex shape like artillery cartridge case are future possibility, but vet none has been made. They show great promise over steel gages. use expected revolutionize chamber practice. Although in. set the mini- mum practical limit for plug gages, some glass makers believe that from the point view mechanical strength, in. more practical limit. The upper limit size about in., but might entirely possible exceed this the use tubing for hollow blown shapes. ment. From present indications appears that substantial portion the gages used large volumes would fall the range between and in. first the basic process which glass plug gages were formed made most economi- cal make the complete gage one piece, whether single double end gage. (See Figs. and Most recent information, how- ever, would indicate that separate glass plugs inserted handles will more satisfactory. Some the first handles dumb- type plug gages had round han- dles. the future, these will made hexagonal shape that they can readily clamped fixed set-ups. This frequently done, for example, gaging the mouth bore large artillery cartridge cases where requires two hands manipulate the case. For this kind set-up, single-end plugs obviously used. Incidental- ly, such arrangement good Msurance against the though rigid holder dis- chipping. The size range ring gages and Thickness the blank der obtain the strength against accidental shock and breakage. (See Fig. 4.) the event possible the “precision shrinking” Process, described later, for form double end plain plug gages. Later designs will have rounded pilots the ends minimize chipping. (See Fig. 9.) forming the bore hole, es- sential provide retaining frames, Fig. for insertion the annular gage whose wall thickness would probably not more than in. Such frames can made wood plastic other non-critical materials. The overall cost such gage will probably very low. Snap gages can best made glass sizes ranging from in. between the jaws, particularly for gages with relatively short legs have great enough provide reasonable mechanical strength and resistance impact. The combina- tion ring and snap gage shown Fig. for example, has thickness in. Gages with jaw openings between and in. can strength- ened wood frame. men- tioned before, glass has one notable advantage material con- struction for snap gages: drop- ped, glass snap gages can not sprung. They either survive di- mensionally unchanged break. Profile gages, such the one shown Fig. can molded dies ground directly out plate glass. Use rounded wood frame cemented the gage necessary protect such gage from chipping and breakage. Thread gages made glass are considered impracticable. Although entirely possible mold coarse threaded sections glass, the re- sultant structure mechanically weak and subject chipping be- cause concentration stresses thin sections and edges. How Glass Molded present, the font molding tech- nique glass manipulation appears best suited produce accurately the odd shapes and heavy sections required for gage blanks. The molds proper are open-and-shut type” and fitted with cup font receive the molten gob glass. plunger then forces the glass through connecting channel gate into the mold cavity man- ner similar injection molding plastics. Upon removal from the mold the overflow cracked off the blank. Ordinarily o.d. variation the glass blank about 1/32 in. would expected, but would possible attain closer tolerance ranges special attention during the molding operation, accurate fin- ishing mold insert, special selection after the blanks are mold- ed. Such font molding will result slight fins diametrically opposed the mold seams, since the die split. Such molding could used for the production blanks from which ring, plug, snap and profile gages would made. One more other molding techniques might have certain ad- vantages for production some the shapes referred to. For exam- ple, might possible attain 4—Glass ring gages are made fairly thick reduce breakage. proposed that small hole molded the body for looping holding string through it. — 1 Chamfer - 23 THE IRON AGE, February { ° ° ° ® “ “i \ 4 \ 64x95 NOT - » Precision shrunk glass ring Wood plastic 5—Proposed design ring gage made from tubing precision shrunk around accurate alloy steel mandrel. Only few need allowed for lapping final size. Such gages can made for fraction the cost steel ring gages. accuracy the ends plug gages blowing into specially de- signed molds special composition. For ring gages there some pos- sibility that the process known “precision can em- ployed subsequently reduce the amount finishing required. This basically heating glass cylinder mounted special alloy mandrel corre- sponding size until the glass soft- ens. applying vacuum pres- sure, the glass forced down the mandrel and reproduces its surface finish, contour and dimensions faithfully. This precision shrinking process will only .be applicable those instances where the coefficient expansion the glass and the metal mandrel differ widely enough permit the mandrel shrink away from the internal bore the glass tube when both glass and man- drel are cooled. For certain sizes and types plug gages, most the larger sizes, in. o.d. greater, might considerably more eco- nomical use machine drawn glass tubing the basic material. Such tubing can drawn and specially selected rather precise o.d. toler- ances, and can made with walls rather substantial thickness. Physical Properties Glass Glass differs from metals and al- loys primarily that composed oxides metals rather than the metals themselves. Also amor- phous rather than crystalline structure, and this largely accounts for its relatively low tensile strength and The ulti- mate tensile strength glass ranges between and 15,000 per 38—THE IRON AGE, February 1943 sq. in., Whereas its strength com- pression enormous—at least 100,- advisable when designing gages made from glass utilize com- pressive strength the utmost, and those instances where tensile forces come into play, the use protected from chipping am- ple beveling rounding edges, Much such beveling rounding can formed the meld, thus shortening the time required for grinding. should appreciated, however, that slight chipping the outer edges the gaging surface heavier sections can made overcome relatively low tensile strength. strength and because glass does not cold flow, its impact resistance much less than that metal, but eliminating sharp corners use heavy sections, impact resis- tance (or resistance dropping) can greatly improved. might possible further safeguard gages from breakage mounting them simple frames wood other resilient materials, also use soft resilient flooring the gaging bench. Glass dropped onto wood floors, for example, has much greater chance survival than when dropped onto concrete steel. Fiber board Celotex tops can used the gaging benches. When properly designed and used with reasonable care, there need little chipping result gaging operations. Plug gages, for exam- ple, should include short pilot with rounded beveled contour; simi- larly, the holes ring gages can etch sand blast 6—Design combination ring and snap gage does not impair the gaging tion. Although glass relatively brittle, highly elastic and has practically straight line stress- strain curve the point fail- ure. Being non-crystalline, re- markably resistant cold deforma- tion permanent set such takes place metal due slippage places weakness crystals. Glass has wide range modulii elas- lb. per sq. in., depending upon com- position. spring material has very low hysteresis loss and always returns its original shape, gage material. the average person, one the first questions that arises refer- ence glass gages that fragil- ity. one commentator facetious- put it: “One advantage glass gages that you drop one, least you don’t have pick Actually, some the newer are much more shock proof than commonly believed. DBPMPdgvyf | 8 | for ed, the ace fune- has re- takes Glass 10° com- and shape, the fragil- glass up.” Glass always tension since its tensile strength only about 1/10th its compressive strength. Furthermore, like any other material, weakest the surface. view this fact, improve impact resistance, use can probably made tempering process which compressive en- velope set the glass off- set tensile stresses that might cause fracture from chipping. Tempered glass produced heating the ob- ject the plastic range, then plunging chilling medium long enough set the outer skin. Then the piece withdrawn and the inner core allowed cool slow- ly. Since cold plastic deforma- tion can take place, the inner mate- rial tends shrink away from the outer ring, which thereby pre- loaded compression. Before any tension stresses, such occur bending, can become effective the 7—Profile gage for.a shell nose. Such gage could ground from molded blank from piece plate glass. layer, they must first over- come the bound-in compressive Frankford Arsenal plug made this manner spe- glass manufacturer New Jersey was struck against the side steel gage without damage. The latter was dented one the edges. Then the plug gage was used drive nail through pine board. Again, the glass gage suffered This tempering process, the one hand, and the precision shrink- ing process for producing female type gages the other, will each important factors the future development and refinement glass gages. There are also great variations the hardness wear resistance glass compositions. Because fria- bility and lack cold flow, their hardness cannot measured Brinell Rockwell readings. rough comparison afforded Mohs scale mineral hardness, which quartz and diamond 10. this scale glass ranges be- tween and The boro-silicate (heat resisting Pyrex) glasses with their very high silica content are among the hardest and most abra- sion resistant glass commercially available. fact, they are almost three times resistant sand- blasting ordinary window bottle glass made soda-lime com- glass has only 1/3 the thermal expansion most metals, including carbon steel. Hence they are not usable for gages without modification. The linear coefficient expan- sion standard boro-silicate for- mula in. per in. per deg. compared with 0.0000060 for carbon steel. The Ordnance De- partment’s tentative specification for glass gages calls for coefficient 107 Corning present developing special glass composition having Initial diameters 1.0265 IG. 8—Sectional view glass ring gage 1.026, 0.000 0.0006 in. nominal size, which was tested with plug shaper set-up. The reference letters indicate the three points which the diameter was measured for wear. The diameters start test are given. tance, coefficient expansion, me- (CONTINUED PAGE 98) 9—Redesigned plain plug gage with rounded pilot minimize chip- ping gage end. Grind the best combination properties such hardness, abrasion. resis- 0.77 MIN. DEPTH INSIDE DIA. Acid etch sand blast marking 45° NOT DIA STEP MUST NOT BELOW FLUSH THE IRON AGE, February 0405 Grind I INSIDE DIA ” . ' - ' i i Oo < < St to c heck « 2 = y 0/25 ad ‘ | } I ° ° QS s+ 4 Prlot A te than Boron conservation strategic materials the manufacture special quality alloy steels has caused rise the use boron intensifier and the same time has placed this fully entitled more than Army-Navy “E” award. This element which the metal- lurgical fraternity has had but interest, forth important partial sub- stitute for number strategic elements. Its use cast iron pre- dates its adoption the steel in- dustry, but has been found that boron the amount 0.003 maxi- mum, when used for obtaining cer- tain physical properties, can substi- tute for per cent nickel, chromium, points manga- points molybdenum. The effect boron increase the depth hardness heat treated piece steel and with this crease ultimate strength and elastic limit the steel also ob- increase ductility steel when the tensile and ultimate are maintained similar that the untreated steel. cast iron, has been found that the addition from 0.02 0.12 boron has the effect increas- ing the hardness, refining the grain, and increasing the wearing quali- ties the iron. Likewise, substitu- tion for some the commonly used elements possible making ju- dicious use boron and balancing the mixture. method adding boron for maximum recovery the mak- ing cast iron add the spout the liquid metal runs into the ladle. the case steel, ferro- boron may added the ladle after all other additions have been made. Some steel companies now split the addition into five parts, adding the ladle fills and get- ting all before the slag starts. The story boron involves the research the Molybdenum Corp. has been interesting. was 40—THE IRON AGE, February 1943 Steels Increasingly natural delve into the possibili- ties further increasing the use boron boron alloys since the company had for some time made various boron products. Metallurgi- cal literature contains only meager amount information and patent literature was also found little use exploring addi- tional possibilities boron. Since boron has always been high priced material, one the things that has been necessary produce alloy which would readily dissolve and which would permit high recovery boron when dissolved the ferrous metal. After investigating great num- ber alloys, the company finally developed the alloy which now regular production, namely per cent carbon, per cent boron, per cent silicon, balance essentially iron. has been found that this alloy has low melting point, that readily dissolves liquid cast iron and steel and that the recovery per cent. that apprehended Some difficulties might have been “never happened.” For example, one the hardest constituents known boron carbide, and were this dispersed throughout the steel, machining difficulty would encountered. But, since boron car- bide formed very high tem- perature and under conditions not usually encountered steel making practice, not likely that this would occur unless the form from which boron intro- duced favored this. The question was, did it? now boron car- bide has not been identified any ferrous material which the com- pany’s ferroboron has been added, and quite justifiable say the ferroboron addition. Boron carbide, when present, can read- ily identified. When boron carbide itself has been added certain tool steels, not dissolved the steel but retains its identity boron carbide even after the steel has been melted, rolled and shaped into its final form. way has com- bined with the other elements the steel. Since the presence boron car- bide was not detected, the next step was attempt identify the form which boron appears steel, and the same time, account for its extra strength endowing properties. became necessary delve into the phase diagram boron, bon and iron. This investigation was greatly aided some research work performed Dr. Clark the California Institute Tech- nology; subsequent work the Molybdenum Corp. great amount the data presented his thesis has been substantiated. produc- ing large number and recognizing new constituent, trac- ing through various additions steel, believed that the new ide—iron carbide. First efforts were the manu- facture cast iron where was known that hard alloy consisting nickel and boron had been used with apparently results. was thought that the physical properties iron could increased and, therefore, work was initiated with man- Co., Pittsburgh. Adding known amounts boron cast iron, its effects were noted. First perceived was that iron which already had large percentage hardenability was turned completely white amounts from 0.12 boron and up. was the amounts less than 0.12 that the greatest interest was attracted since was desired know what happened the iron which contained boron but which was not sufficiently strong car- bide formation properties pro- duce white iron. After number experiments, was shown that the addition 0.05 boron these roll-type analysis irons increased the physical properties such way give longer life when the rolls were use the mill. Accord- ingly, the addition 0.05 per cent was recommended, and has been shown that this amount the step orm and into tion lark ech- the duc- and rac- new bor- anu- was used the iron fore, man- nown its eived had bility than was iron which that these reased uch the cent been Favored rily effects finer grained struc- ture, slight increase the hard- ness and reduction the col- umnar structure which generally evident the chilled cast iron roll structures, especially when large mass involved. Subsequent work has shown that positive results may obtained this type iron down 0.02 per cent and that higher silicon irons and others with low percentage hardening elements their compo- sition, much 0.19 boron may gainfully used. Today very good percentage cast iron rolls contains boron, and found possible reduce some the other alloys small only slight increase the per- now dictates that for each point boron added the cast iron the creased two points, and that when the boron increase 0.10 per cent the silicon replace- ment should figured three points for each point yond 0.10 per cent. The melting cast iron scrap containing boron first represent- problem because satisfactory method determine the amount boron that was retained wher re- melting the scrap was not available. However, now known that about per cent recovery the boron the cast iron obtained remelting. The type melt- ing turnace has some bearing the boron recovery when remelting scrap, but for the average alr type the per cent recovery seems approximately cor- The method approach the essentially the same that cast iron that the boron cent, only find that the steel Was not The boron con- tent was then divided into one-hun- dredths per cent and again Was found that the steel with little 0.01 boron would not roll out just how small quantity NORMAN TISDALE Metallurgical Engineer, Molybdenum Corp. America, Pittsburgh Knowledge influence ferrous metallurgy expanding rapidly, and this element has already les- sened the pressure certain strategic elements. Herein, the author describes many the development stages the utilization boron carbon and alloy steels, and sets forth the present status the technique. For addi- tional information boron, see THE IRON AGE, issue Nov. 19, 1942. could put into steel and make rollable. After making various heats steel, adding from 0.001 0.010 per cent boron, was found that the steel exhibited hot-short prop- erties with little 0.007 per cent boron added. Idle curiosity prompt- the desire see any good could derived from 0.007 per cent, and shown, approximate- from 0.0025 0.0030 per cent gave the best results. this range greater depth hardenability was achieved. Also, was noted that there was change the properties the steel unless were quenched and drawn and that greater response the effect boron was shown under low draw- ing temperature rather than the high. Since there were accurate methods available analyze for such small amounts boron, prac- tically all the early work added amount boron was ried out while not knowing exactly how much was left the steel whether was uniformly distri- buted. Within the past six months the chemical department the Campbell works Youngstown Sheet Tube Co., Youngstown, under the direction Russell, chief chemist, has worked out colorimetric method which sufficiently accu- rate for control work. Also, Berger, research metallurgist, Mo- lybdenum Corp. America, has been instrumental working out successful spectrographic method for the determination boren these small percentages. Using these methods determi- nation for boron, was learned that the optimum amount boron for best results 0.0025 per cent tained boron. This figure was ar- rived after testing many heats steel made both electric and open hearth furnaces. The important point connec- tion with boron additions steel that extra properties are tained through heat treatment. This heat treatment primarily liquid quench and draw, although some results have been obtained from air quenching other hardening elements were present aid the penetration hardness. The facts interest are that boron will increase the penetration hardness and doing, automat- ically increases the elastic limit and the ultimate strength the steel. Little change will noted the ductility unless has been found desirable maintain the ultimate strength level equal that untreated steel, and when this desired increase the ductility can expected from boron treated steel. After discovering would impart greater penetration hardness, became necessary develop methods which were mainly control. was soon noticed that the addition boron steel gave coarser grain size than one with- out, but was also found that some the well known grain refining elements such aluminum, titan- THE IRON AGE, February ° ° A 30} = Third ingot Distance from water cooled end sixteenths inch hardenability tests for “boron This low C-Mn-Cr-Mo steel, and ferroboron was added per ton. lum, zirconium vanadium could quite easily compensate for this since the change grain size was only the order one two numbers the coarse side. other words, the steel normally would have grain size, the steel plus boron would likely give steel grain size Using aluminum alone rectifier for this coarsen- ing effect, recommended that should added the boron treated steel. Naturally one the first physical properties investigated was impact values. The lower impact values obtained were not explained the coarsening effect. This phe- nomenon, however, has been shown the result mixed duplex grain size. After producing number heats steel, was found that where the silicon con- tent was held minimum other conditions the manufacture the steel were normal, this du- plex structure was not encountered. The present method includes the specification 0.18 silicon minimum, num compensate for the coarsen- ing effect boron. has now been reached where grain size steel free from duplex structure being produced which gives comparable with that steel which boron has not been added and ductility 42—THE IRON AGE, February 1943 figures which are every way equal the non-boron steels. order obtain the highest recovery boron, practice has been developed whereby all deoxi- dizers and grain refiners are added the molten steel the ladle fol- lowed almost immediately the ferroboron addition. The high solu- bility the ferroboron allows the boron become dissolved almost immediately, and the writer now confident that between and per cent recovery the boron added the ladle being obtained. recommended that the amount ferroboron divided into four five portions, adding the ladle fills and getting the last por- tion into the ladle well before the appearance the slag. The im- portant thing that the boron should added well deoxidized steel and that should dissolve rapidly the liquid steel. may stated here that the original work, mold additions were used determine the effect vari- ous grades steel, but obvious that this method not nearly suf- ficiently uniform give accurate control for regular commercial re- sults. However, from the mass information which now available, most steel companies have familiar- ized themselves sufficiently with the the ladle and secure uniform re- sults. Some doubt has been expressed obtaining even distribution the boron throughout the heat steel. Some have thought neces- sary produce diluted boron alloy and add number the other known elements which would protect the boron from oxidation. the steel made with Molybdenum Corp. ferroboron there instances where there has been concentration boron any localized effect. safe say that were this difficulty encount- ered, some evidence been submitted the steel com- panies using ferroboren. date such evidence has been brought 2—Physical properties SAE 1035 and SAE steels. quenched 1500 deg., drawn 1000 deg. Sections are in. 120 1000 per sq.in ~O Tensile and yield strength Tensile Yield SAE 1035 BORON: Percent reduction Per cent area elongation or- the ron zed the ere ari- ous suf- rate re- ible, re- ssed ition the ition. been been any say have com- date Evi- dence has been collected from heats steel varying from ton 250 tons. Samples have throughout the heat and both chem- ical, spectrographic and hardenabil- ity tests have shown that very uni- form results are being obtained and that segregation boron exists any these heats. glance Fig. will show the Jominy hard- enability test taken from the center ingots from the first, middle and last 250-ton heat steel, and these results were both satisfactory and uniform. While most the work was orig- was necessary check into the grades, and found that steels with carbon content from 0.20 0.60 per cent are more re- ceptive and responsive the boron addition. the case low carbon steels, 0.20 and under (especially those the carburizing the extra penetration hardness may produce too high core and hence might necessary reduce the manganese content. some cases the manganese content can only reduced certain amount, which will still sufficient make satisfactory rollable steel, and those cases, the boron tion necessarily reduced. The additional physical tained boron are practically proportion the amoun: used 0.003 and, therefore, the case low-carbon steels which are used for carburizing purpose, most applications now call for the addition 0.001 0.002 per cent. the case carbon steels above 0.60 carbon, condition found where the hardenability has been carbon that the user maker Steel faced with using either lower carbon plus boron boron larger section the higher carbon steel. example this, grade 0.90 carbon steel size was used without boron, but when the size increased obtained was not satisfactory for the purposes when the steel was heat treated. Therefore, this addition 0.003 boron was recommended and found give Satisfactory results. The addition 0.003 boron steel which satisfactorily Per cent boron the ton steel the ladle will add approximately per cent increased and ulti- strength and this increase sufficiently nigh put number almost equal some the low alloy steels. example this ordinary bolt steel. From glance Fig. may seen that ordinary SAE 1035 steel plus boron will give steel with satisfactory physical properties. the time writing there are applications which are constantly being brought ac OO hardenability. Therefore, the next thought was one sub- stitution. mentioned before, was found that possible take out certain specifications per cent nickel, points chromium, points molybdenum, points vanadium, points manga- nese. While true that the Grossman factor that higher percentages alloys | free Rockwell hardne Distance from water cooled end sixteenths inch 3—End-quench hardenability tests showing the effect ferroboron additions specially deoxidized steel. the writer’s attention, and there sufficient evidence that carbon- boron steels are going fill the gap for many uses future steei re- quirements. Naturally, there was some curi- osity also the alloy steel field. From the results obtained was evident that boron was sufficient potency that might interfere with some the regular alloys. was found, upon experiment, that the boron acted exactly were added carbon steel. words, increased penetration hardness was obtained whose analyses did not give suffici- ent hardenability completely harden throughout the cross-sec- tion. follows, therefore. that there very little advantage gained adding boron steel which, its composition, has suf- could substituted, exact sub- stitution not feasible, since steel making has not yet developed into exact science. Confronted with the fact that some variables steel manufacture cannot evaluated, was found actual practice that boron additions can substituted for amount alloys under possible amount. variation en- ters the picture when two alloys are being used steel composition. Here again found that the rules not follow theory. Hence, only practice that boron can satisfactorily substituted for some alloys, although Dr. Gross- man’s work valuable guide. Since there has been abnorma! drain the country’s sources, very evident that the use boron, the raw materia! for THE IRON AGE, February | | | | | | | } | | — O O | | | | } | | Bate 4 | | } | | | | | | cent gation which plentiful this country, has come most propitious time. estimated that the steel in- dustry producing more than million tons alloy steel month. For such vast quantity steel, tremendous amount alloy re- quired. Any portion these that can offset the use boron will afford that much more flexibil- ity the production satisfactory alloy steels for all uses. ex- ample this SAE 4130, where the chromium limits are 0.80 1.10 and molybdenum 0.15 has been found possible produce whose chromium approximately 0.80 0.85 and molybdenum thereby saving lb. molybdenum and lb. chromium per ton. Car- this through the many grades and types steel and the quantities demanded, the savings possible are considerable. Another angle the use boron that since being substituted for hardenability properties rather than chemical properties, beneficial relief not limited any one ele- ment. the supplies various elements rise and fall, possible utilize boron sort pinch hitter the substitution field for the alloys which the inventories are temporarily low. The industry still without full Specifications for Zinc Alloys accompanying table shows convenient form the com- parable ASTM, SAE, government and New Jersey Zinc Co. alloy specifications. emergency alter- nate Federal specification for build- ‘ers’ hardware, locks and lock trim covered Specification E-FF- H-106. There another emergency alternate specification for plumbing fixtures covered Specification specifications permit the use zinc alloy die castings for certain stipu- lated applications having com- positions conforming Zamak-3, Zamak-5 and special low alumi- num alloy whose composition indicated No. MA. The data are from the New Jersey Zinc Co. 44—THE IRON AGE, February 1943 Rockwell hardness Penetration hardness, inches Fic. 4—Hardenability effect boron 0.65 per cent carbon steel. garding the effect boron. Machin- ability tests indicate increased cut- ting speeds comparable hardness. Creep tests far not indicate any increase from boron. The use boron nitriding steels shows promise. The use ferroboron has grown such proportions that appreci- able percentage alloy steel made today for many purposes contains boron. has been employed many types steels that has carved place for itself not only today the ferrous industry, but certainly will have great role the post-war era. Comparable Government and Commercial Specifications for Zinc Alloys New Jersey A.S.T.M. S.A.E. Navy Army Air Corps Co. B-86-41-T 921 None None None B-86-41-T 46-Z-2 903 None 57-93-2 None 46-Z-2 (Interim) B-86-41-T 46-Z-2 XXV 925 None (Interim) None None Zamak-5 B-6-37 QQ-Z-351a 46-Z-la slab B-6-37 Special High Grade None None Horse Head special slab 47-Z-6b* 47-Z-6* Zilloy (Interim) Specification covers the use zinc alloy for forming dies. There also Air Corps Specification 10302, covering alloy welding rod for use conjunction with tion 11328. product Doehler Die Casting Co., also corresponds A.S.T.M. Specification B-86-41-T, | | 40, | ains has only but 4ead Head slab zine and so an Air heat stresses due mass vary with the type quench and are illustrated Fic. This graph shows the relative dif- ferences existing between the out- side surface and center similar rounds 400 deg. where small amount martensite may pres- ent about form. readily seen that although the total time for outside and center cool bath temperature ap- proximately the same that con- siderable difference temperature exists during ranges. For the sake conveni- ence, the temperature which the initial martensite grain forms called the point. also readily seen that when the tempera- ture the center drops the point and martensite starts form the temperature the outside layers has dropped point where the transformation complete. the cooling rate the center through the range 1300 1000 deg. has exceeded the criti- cal cooling rate, martensite must lorm. This constitutent has lower gravity and the increase the piece often breaks. Provided through hardening desired, the quenching cooling must such that the critical cooling rate exceeded the cen- quenching medium should selected produce minimum dif- ference temperature between the outside and center the point will occur. also readily seen that the could quenched during the medium that the critical cooling MARTEMPERING ... This technique quenching may have great promise for the future, and applicable immediately increase the usefulness steels. conclusion, herein, the author gives data cooling rates, transverse hardness surveys for various steels, and detailed description the salt bath furnace used for quenching. SHEPHERD Chief Metallurgist, Ingersoll-Rand Co., Phillipsburg, rate would exceeded all sec- ture dropped) fairly uniform tions (making compulsory for rate throughout the matrix aus- martensite form) and then trans- tenite. This soft constituent would ferred some bath tempera- cushion adjust the stresses ture slightly above the point, that minimum residual strains held that bath long enough for would result. the center catch the outside the cooling rate obtained the and equalize temperature, then liquid bath (held temperature further cooling could permitted just above the point) would maintain the minimum temperature ing rate the piece could quench- differential between the outside and entirely this bath, equalized center. Formation martensite temperature, removed and allowed would then occur (as the tempera- cool air. The point varies Inside appreciable temperature when outside reaches point and Inside Starts form “much lower emperature that outside and inside through transformation same time transformation Transformation which Mfinish Bath temp. Time 3—Cooling rate outside and center similar rounds quenched water, oil and air. THE IRON AGE, February 1943—45 — f ° ° joys Quench temp. J <a Outside Carbon Tool Steel SAE 4160 1575 4342 1500 0.42 0.68 0.18 4142 1500 0.41 0.30 8749 1500 0.52 0.85 0.21 1500 0.185 0.86 0.17 4063 1500 0.64 0.85 0.29 1500 0.40 1.43 0.22 8949 1500 0.49 1.01 0.20 *Beginning martensitic with salt bath temperature must altered different steels and the quires the parts held the salt long enough equalize tem- perature, followed cooling atmosphere. The operation quite commercial the pieces may held the salt for considerable periods after equalizing tempera- ture with effect upon the results. may not always desirable allow the piece cool air room temperature. the tempera- ture has dropped 150 200 deg. F., fair percentage austenite accordingly. Table shows points for number steels. These data are furnished the courtesy Payson, Eastern Research Laboratory, Crucible Steel Co. America. ' t TABLE Point 380 0.33 500 0.23 0.26 0.07 610 0.55 0.53 0.09 0.23 0.29 0.32 600 0.54 0.56 0.38 535 (Mf point) may still present. Reheating the piece from this temperature range the tempering temperature and holding that temperature long enough isothermally transform strains. This phase being inves- tigated. has occurred among practical men for long time over the value exceedingly low holding times the tempering temperature temper- ing several times provide maxi- mum characteristics. The data illustrated Fig. show the time required for in. and in. rounds equalize when quenched from 1550 deg. salt 400, 500, and 600 deg. (circulated with pump gal. per min.). Time