The Iron Age 1941-01-30: Vol 147 Iss 5

GH, Here Alloy 502 con- veyor belt, 58” wide 47’ long, weight 6100 This alloy gives good service for furnace parts general, for pots and carburizing boxes. the 35-15 type, and 24-12 also available. Both can also had rolled rod and flats. can give you long-life clloys, and money-saving designs. you have heat- resistant problem, can show you how solve it. Write Hoskins Manufacturing Com- pany, Detroit. Right heat-treatment was never more vital necessity than now. Hoskins elec- tric furnaces are meeting this vital need many places. The one shown here equipped with fan insure special uniformity temperature. has 2-zone control and can used 2000 Heating-chamber: 87” long 22” wide 12” high. also make standard box and pot type furnaces, oil baths and brazing furnaces. Ask for Catalog 57-H. NICKEL-CHROMIUM HEAT TREATING FURNACES HEATING ELEMENT ALLOYS THERMOCOUPLE AND = JANUARY 30, 1941 VOL. 147 VAN DEVENTER President and Editor BAUR Vice-President and General Manager Managing Editor News Editor Editor Machine Tool Associate Editor Editor WINTERS Art Editor Washington Editors MOFFETT JAMES ELLIS Resident District Editors CAMPBELL HERMAN KLEIN Pittsburgh Chicago Cleveland Detroit Editorial Correspondents Buffalo Cincinnati FRAZAR CHARLES POST Boston San Francisco HUGH SHARP JOHN McCUNE Milwoukee Birmingham SANDERSON ROY EDMONDS Toronto, Ontario St. Louis LEROY ALLISON Editorial Developing the Picture Technical Articles Enlisting Small Plants for U.S. New Air Gage for Long Bores New Roll Shop Full How Finish Carbide Drawing Dies What's New Machine Tools Feature Reports News and Market Reports Personals Machine Tool Activity..... Metal Working Activity..... Construction Steel Comparison and Steel Prices........ Summary the Ferroalloys, Pig Iron The Industrial Warehouse Prices ... District Market Possibilities Fatigue Cracks Free Industrial Literature Products Advertised Index Advertisers Copyright, Chilton Company DIX, Manager Reader Service Owned and Published (incorporated) Advertising Staff Publication Emerson Findley ice Executive Offices Robert Union Cleveland Chestnut ond Séth East 42nd Herman, Chilton Bldg., Philadelphia Philadelphia New York, Hottenstein, 1012 Otis Bldg., Chicago U.S.A Leonard, 100 East 42nd St., New York Peirce Lewis, 7310 Woodward Ave., Detroit Ober, 100 East 42nd New York Don 1595 Pacific Avenue, Long JOS. HILDRETH, Vice-President B ' Ci loti J. H. VAN DEVENTER, Vice-President Member, Associated Business Papers BAUR, Vice-President indexed the Industrial Arts Index. Pub WILLIAM BARBER, Treasurer lished every Thursday. Subscription JOHN BLAIR Secretary United States and Possessions, Mexico, $6.00: Canada, $8.50; Foreign, $12.00 year. JULIAN CHASE, THOMAS KANE, Cable Address, HARRY DUFFY CHARLES HEALE | 103 104 106 110 115 ACK THE ‘‘GOOD OLD crackers came barrels; and many people bought steel, too, with clear idea what was, how was made. Methods storing and handling were “hit and miss’; results expected were uncertain! Crackers were crackers; steel was steel! different today both! The Ryerson plan Certification provides definite data every ton the steel the vast Ryerson stocks. You know the steel you’re getting. You have accurate information its chemical and phys- ical characteristics, its strength, hardness, heat- 26—THE IRON AGE, 30, FRESH, — — 4 SURE ARE, MRS.PERKINS treatment response! You can select Ryerson Cer- tified Steel with positive assurance that the kind and quality exactly suited the job you want do. Ryerson stocks are complete; shipment im- mediate! One the ten Ryerson plants, conven- iently located near you, ready serve you. Get acquainted now with the many advantages this modern steel-service. 1940-41 Stock List will sent promptly request. RYERSON SON, INC., Chicago, Milwaukee, St. Louis, Cincinnati, Detroit, Cleve- land, Buffalo, Boston, Philadelphia, Jersey City. ——— W — \ | — ===: = JAN. 30, 1941 ESTABLISHED 1855 Developing the Picture OSSIBLY some you who read this page are amateur photog- raphers. so, you will have observed what have connection with the development picture. Quite sequence events takes place before you can see what you've got. First, you have start with the camera. Then you have load with film. That just the beginning. Next you have find the scene that you want take and that may mean considerable legwork; even headwork good picture. Then you have appraise the conditions lighting and estimate the speed exposure and the stop. Then you press the button. You now have the picture—perhaps—but you see what you've got. Next comes the process development which you get the finished negative. But still you see the picture because the negative black white and white black and hard for amateur photographer reverse images his mind for amateur molder see things the “hollow” instead the solid. you make print exposing sensitized paper the light through the negative. And all you have result, yet, plain white sheet paper. You are getting close the picture; very close indeed, yet this stage events, you did not know photography, you would think that you had missed the boat. But least hoping that you haven't, you get ready develop the print. The maker the developer tells you that the developing time two minutes. goes the blank sheet paper. You watch intently see what happens. Thirty seconds, forty-five, sixty, minute and quarter. Still just plain blank sheet paper with forty-five seconds go. flop? Five seconds more and discolorations appear here and there. You can't recognize them. But second after second from then on, with in- creasing acceleration, the details build fast that when the two minutes have passed, there your picture, clear and distinct every detail. Our National Defense effort like that. Lots and lots preliminary groundwork with little show for until the nearing the end the process. And then will all come together with surprising suddenness that will amaze and startle the world. Remember this analogy when you hear people complain about things going too slowly. Most want see the finished picture right after press the button. But out! { | | | | 4 | | | j | y t —in Every Pound Inland Inland Steel Company has always an- Inland research has given industry such valu- ticipated the exacting requirements the able steel mill products as: high-strength, low metal working industry producing finer, alloy Hi-Steel; lead-bearing, fast machining more uniform steel. For over years, Inland Ledloy; finer cold reduced tin plate; Inland research has been directed this objective. was among the offer the superior qualit every then known scientific method was ap- Inland steel plied making its products. first, methods and control devices centered making better harrow teeth, plow which steel finer quality and greater uni- beams, merchant bars, etc. the years have formity are made. passed, Inland not only has added greatly Today, every pound Inland Uniform Quality its physical plant, but also has greatly expanded Steel has back over years intensive research and metallurgical facilities. research. PILING RAILS TRACK ACCESSORIES REINFORCING BARS MILLIONS DOLLARS SHIPMENTS MACHINE TOOL 100 500 Enlisting Small Plants For Defense JAMES ROWAN News Editor OBILIZING the full man power and machine power American industry for the nation’s defense this week getting the attention more and more leaders industry and government. The problem bulking one the most important confronting the defense program. How can the small plants brought into the picture secondary con- tractors? necessary that they brought in? Can big business alone handle the job defense goods production? Must industry develop its own plan machinery? some these questions defense leaders were getting slow and painful answers. The nation has scores giant companies but has also many thou- sands small metal-working companies. the face reports shortages machine tools for defense plants, was estimated that per cent the nation’s existing machine tools are, for one reason another, idle. Large companies holding original contracts are con- templating the headaches doing business with scores and scores small suppliers who might, the large concerns, complete “strangers.” They are thinking the inconvenience, delays deliveries, specifi- cation troubles, shortages materials, tools and men, lack credit, lack technical experience. And small contractors, still for the most part shut out defense contracts, all over the country are clamoring for second and tertiary defense orders for their idle partly idle plants and employees. assortment plant surveys being made assortment agencies. The giant them all the national plant inventory initiated recently William Knudsen, director general theg Production Management, and carried the National Industrial Council. All seek data existing and re- gardless size. all this natural that the emphasis tools, whose builders have been forced draft for several years. And 1936 the need for utilization the great reservoir un- used machinery small plants grows more urgent daily. THE IRON AGE, its own survey the thousand- phased problem small plant mobilization, finds that, obviously, the only hope many small plants for par- ticipation the armament program obtain work from holders prime contractors, and that the very size these small shops makes difficult for them approach the prime contractor who trying produce his contract entirely his own shop farm out only the units that sub-contractor can manufacture their entirety. One the highly-placed men the defense pro- gram told this writer that—unfortunately—some com- panies regard the move ‘to spread defense contracts “political.” said this untrue and that the success the defense program rests large extent bringing small plants into defense production. Large-scale sub-contracting, said, this time transitional period, and the course will take will depend largely industry itself. Everyone authority, said, looking for ideas how this utilization small plants can quickly and efficiently brought about. far, too little thought effort being given farming out thegyork “bits and pieces” and only through every last screw Too thought has been the util- labor unsettlement resulting from order large plants, using idle machine power work for which best adapted. Here and there industry, efforts solve the complicated problem small plant utilization are getting results. Out the generalities are coming realities, such the sub-contracting plan set the Kearney Trecker Corp., Milwaukee, for meet- ing the great demand for milling machines. (At pres- ent the lack horizontal boring mills equally problem. 1937 1938 i 3 1 | 600 q 4 | ° ° | | | 4 | | 300 | | | Kearney Trecker, forced large orders for mill- ing machines, has established Outside Work De- partment handle its (latest count) sub-contrac- tors. The task handling sub- contracting was too time departments. Other tool manufacturers not, able profit from Kearney Trecker’s Sub-contractors for the the Kearney Trecker milling came from four sources. They are (1) the list customers, (2) its list dealers, (3) friends, and (4) volun- teers. When the Trecker production depart- ment calls the Outside Work for aid, the wheels organized sub-contracting department roll. (E. Boettcher, present manager the Outside Work calls his department “applied common sense depart- ment,” but this division cannot written off The Outside Work Depart- ment digs file search for outside plants capable the job. Naturally the Kearney Trecker find “stranger” plants making mill- ing parts under its own cost conditions. plants all prospective sub-contractors there are major minor” operating factors. One plant may Better cost position regarding grinding, milling some other operation. possible, the work done broken pieces and each piece allocated the plant best equipped the job and the one which fair profit. The selected small (large cases) plant must able determine exactly much time will consumed doing the work; must able guarantee that will meet the schedule since that most essential. Since the Milwaukee company and other companies, some whom have done equally outstanding job sub-contracting, operate their plants against price list, the company must select the best work for the best-fitted supplier that the latter can make profit. This results retaining his interest sub- contractor and enables depend him for continuous flow materials. Acknowledgment the small plant’s right profit rests the heart RGANIZATION the Kearney Trecker De- partment Outside Work presents interest- ing setup. (See the organization chart page 33.) coordinator gears the department the main organization. Under him are six divisions which considers almost equally important. These are correspondence, engineering, progress, inspection, shipping and receiving and purchasing. tion the postal costs and telephone tolls sub- contracting program such Kearney Trecker’s provides evidence the activity the “correspon- dence” department. Hundreds inquiries from sub- contractors must answered, other hundreds sent out. The inspection division the Department Outside Work includes inside inspection—of the parts and complete milling machines coming the Milwaukee plant for final test—and outside inspec- tion. The Department Outside Work has total inspectors which are inside and four out- side. Progress reports from sub-contractors are vital part the plan and periodic inspec- tions help keep delivery schedules. Six men are detailed obtain progress reports the company’s contracts. The Engineering Division includes sub- groups for tolerances, design and duplicate tools and fixtures. The Kearney Trecker plan sub-contracting has been selected unique the War Department, hence Messrs. Joseph Trecker, vice-president, and Francis Trecker, assistant chief engineer and former man- ager the Department Outside Work for the Mil- waukee company, have been assigned posts the War Department’s planning division assist considerable importance the defense program, the eyes the small plant operator, the subject credit. Banks, for the most part seem anxious cooperate financing defense production, this writer told. One large Eastern bank, for example, notify- ing its customers through advertising and other agen- cies that: “In connection with the national defense program many companies are being invited bid orders not only for products their regular lines but also for products that they are competent make but which may not related their normal production. This may require alterations additions, installa- tion special machinery, and may bring about need for additional working capital. The (name bank) desires participate the financing such require- ments, not only matter good banking but also because its desire cooperate with the nation’s program. “We would welcome opportunity discuss with business executives any needs their companies may have these respects,” the bank concluded. small businessman wants sub-contracts should get acquainted the banks defense basis. may not need borrow money now but the time may come when will need cash expand his plant for making defense goods. should provide complete descriptive list his equipment seeking sub-contracts, and get complete list the primary contractors with whom may business. Much correspondence from small companies the primary contractors vague and highly indefinite. should not write letter like this: Steel Products Corp. Gentlemen: hear you have received fense contract some sort other and would like ture parts for your company. Please answer your earliest convenience. Sincerely and hopefully, (signed) Would—be i] ~ i - i| i] | | | | 4 i | j | | | j y ip q q q a q Trecker Urges Location, Utilization Existing Defense Machines First Step Preliminary studies the prob- lem bringing together exist- ing manufacturing equipment and the demand for such facilities de- velop variety lines for action. one line find the long term plan which envisions the “ghost town” rehabilitation; the “kitchen” production “bits and pieces” and several other related schemes ac- tion toward complete and “all- out” effort for obtaining production every sense the word. The next line the problem fitting out for current “on order” needs, for the fulfillment already contracts. This line devel- ops the utilization existing small Joseph Trecker, vice-president Kearney Trecker Corp., Milwaukee, and his brother, Francis Trecker, assistant chief engineer that com- pany, have been designated the National Defense Advisory Commission cooperate bringing small plants into the defense program sub- contractors. JOSEPH TRECKER* and possibly unused facilities permanent part the production plan farming out parts eliminate additional unnecessary creation material facilities. This step possibly the most important and farreaching overall effect, and makes possible minimum labor displacement and the small- est economic disarrangement our normal peacetime productive facilities. Another and immediate line action, and one which may afford relief for the harried contractor key material, the locating existing equipment which has been sold within the last years, determination its present use and availability and contracting for for unit processing, such planing, grinding, milling, effectively tide over the contractor until his “on order” equipment delivered. This step will result the continued use emergency has passed, and effect permanent “farmed out” system. These three lines action re- quire time take effect, and varying degree planning and preparation. The first course, reason its most farreaching ac- tion, requires the greatest length time. The second the mo- ment more possible and more easily envisioned, but involves vast amount detailed study and in- vestigation well considerable persuasion effect coordination the needs, with the facilities available. The third (locating and utiliza- tion existing equipment) immediate importance and concern, and can begin its move from reli- able sources and extend quickly into reliable advice through con- tracting offices the neediest and Letters like that are the files most the com- panies which have received original defense contracts from the various government agencies. Nothing much can done about them. Instead, the small industrial leader should decide what his plant best equipped and provide full information the prime contractor. sure the prime contractor knows all about the company. Then the same information should given the district government procurement office, which many cases will the Ordnance District Office the War Depart- ment. the same time this information should given the Federal Reserve Bank branch bank representative who has been designated Donald Nelson, the National Defense Advisory Commis- sion, coordinate the efforts small businessmen obtain defense business and the efforts prime contractors get the assistance these small busi- nessmen. Information offered the prospective secondary contractor should include the present rate opera- tions his plant plants. Naturally, plants now idle working only part time will, other things like equip- ment and location being equal, high the list factories brought into the defense picture. The head the small plant should list the number various skilled employees his payroll and should provide the district procurement offices for the vari- ous government agencies and the Federal Reserve Bank small business representative, with prospect most pressing wants. list prime contractors with whom might busi- ness. plant may operating 100 per cent capacity from the viewpoint its management but partly idle from the viewpoint national defense. plant getting out its completed products rate 100 per cent includes shop with battery machine tools operating only hr. day fill the plant’s needs, the plant not operating capacity from standpoint defense. The idle machine capacity small shop may vitally useful some department some nearby plant making products urgently needed for defense. The lifetime such overloaded machine tools would doubt shortened under such “machine lending” system but the machines can replaced and their fullest possible use might help lengthen the lifetime the American industrial system. Machines that are fully utilized defense production will wear out more quickly but the need for their over-loading great. Such over-loading will create replacement market for machine tools when the emergency over. this emergency idle machine like deserter from the army, the industrial army which the mili- tary army depends. this emergency the emphasis placed heavily PRODUCTION. The most casual survey the nation’s defense needs and its present efforts fill these needs suggests that much idle capacity masked the high operat- ing rates many plants. The small plant owner THE IRON AGE, January 30, q 4 | | | | | | | | } | j ; should get the habit asking himself questions like this: “Your horizontal boring machine may working only part time for you. Can work the remainder the time for someone else?” Among other steps which are likely taken for defense the use plant visits. The prospective sub-contractor must study the products prime con- tractors and determine what part what process can produced carried his own plant. Wherever possible must get into the plants the prime contractor, that his representatives can see what being done. will see operations that can himself, parts that can make, shortcuts that can take his own production. the large companies each the scores industrial districts the were permit inspec- tions defense production their own plants metal-work- ing companies without prime de- fense contracts ISTRIBUTION sub-contracts from the core" 1850 companies which have received prime de- fense contracts the 6650 metal working companies which have not received prime contracts one the National Defense Advisory Commission's biggest prob- lems. (The 8500 metal-working establishments these above totals have annual productions above $100,000. They the business the metal-working industry.) 1850 mass scale, say hundreds small makers metal products (after the visitors had been looked over the FBI), one step toward successful utilization America’s small plant utilization defense would have been taken. Some system may worked out whereby small plants, with their less efficient equipment, may con- centrate filling orders for commercial products. Then the larger companies, better equipped for manu- facture highly specialized war goods, would more able concentrate that class products. Metal working companies with defense orders over $100,000 growing clearer that what the small plant operators can help themselves and the nation considerable. They can, for example, pool their resources did number plants York, Pa., and deal with the original contractor that group small com- panies can handle secondary contract which may far too large for any one them handle alone. They can familiarize themselves with the equipment nearby plants and determine where their various capacities for metal working complement each other. small plant has grinding capacity which per cent idle, the fact should broadcast. plant 32—THE IRON AGE, January 30, with turning milling capacity only per cent utilized not doing its share national defense and should forced into full production. Chambers Commerce and trade associations can and are helping and, European experience mobil- ization industry followed, will given great powers and great responsibilities. Nevertheless the formation small units metal products companies —and makers other defense goods for that mat- ter—within these broad industrial and business groups seems desirable. The American Iron and Steel Insti- tute and the National Machine Tool Builders Asso- ciation already are doing highly valuable work and are getting results. the same time, the broad geographic distribution industrial plants suggests that the work these associations speeding production should supplemented the development “Good Units” metal-work- ing companies. After organizing, these small com- panies, longer small when viewed “defense unit”, can publicize their ability take sub-contracts and some cases prime contracts. Acting units these groups small companies. operating, for example, under name such the “Mahoning Defense Plant can make their existence known and can obtain the business which they want and which the government and every defense production leader wants them have. Such defense units evidently are among “the things come.” study defense production suggests that the small companies can combine their equipment, their technical facilities, their supplies skilled workmen, and their selling facilities. They can seek business along geographical lines. Above all they must make known what work they can do, what needs they are equipped fill. Isolated small plants have somewhat more com- plicated problem but under “all out” produc- tion cannot allowed stay idle. Wide distribution the new airplane and munitions plants planned and already being built relatively isolated communities throughout the country will help such companies. Thus isolated plants, with useful equipment which can used producing some the thousands items needed for the defense program, should familiarize themselves with these new government-financed de- fense plants their own territories. some cases. new industrial communities existing beyond the end this war may grow around these plants. the case the isolated plant, the case the plants some the highly congested industrial areas where factory units fill unbroken miles, thor- ough survey equipment required. Equally neces- sary analysis idle periods and study the long list parts and metal-working operations neces- sary production the guns, planes and other highly complicated war-making machinery today. The isolated plant must broadcast its ability manufac- ture defense goods has this ability. Otherwise the full industrial capacity the cannot brought into full production. Lack knowledge what required the manu- facture war equipment production evidently substantial obstacle the greater utilization Amer- CORRESPONDENCE DEPARTMENT OUTSIDE WORK SHIPPING AND RECEIVING ENGINEERING INSPECTION DUPLICATE TOOLS AND FIXTURES DESIGN CLERICAL INSIDE DETAILED GENERAL HIS organization chart describes Kearney Trecker Corp.'s Department Outside Work, which Boettcher manager and coordinator. Kearney Trecker's plan considered model for subletting defense contracts and bring- ing small plants into production for defense. (Number employees each ica’s small plant capacity. Some system circulariz- ing the thousands small plants with information about defense needs eventually must found. will matter education which the large industrial units with their large research and engineering de- partments, their ample organizations for obtaining vital information will play part. Much information about defense orders circulated word mouth, “random” method information exchange. railroad man with natural interest increasing the volume traffic his division will pass along defense order tip plant along his road with the suggestion that the plant may get some the business. Utilities likewise are serving information agen- cies and are, some cases, keeping their customers light and power posted the status specific prime contracts. Industrial publications are posi- tion provide thorough-going service keeping the prospective sub-contractor posted methods utilizing all available sources information that the small company will keep itself line for orders 1941. this stage the building defense, the facilities for direct exchange information about sub-contracting are not very highly developed. Exhibits manufactured defense goods plants, associations, would helpful, the opinion some industrialists. This being done Detroit. Technical associations, national and chapter meet- ings, are hastening the education small industries but this educational process speedup needed. some quarters suggested that prime con- tractors must make greater effort assist small companies, that the inspection the big plants, where this feasible, should accompanied inspection small metal-working plants large scale “travelers” from the large plantse Undoubtedly the organization periodic “small company” discussion meetings some the large plants would bring more the smaller plants into the production picture Groups small plant operators must taken into anti-aircraft gun plants, for example, watch the full manufacturing process from blue prints loading finished products into cars. Obstacles toward utilization small plant capacity defense goods production are frequently talked about. They exist. When the urgency defense more clearly understood over the next few months, some these obstacles will not appear very important. The small company which would defense sub- contractor must understand its own capabilities the way plant capacity and personnel. The next step publicize fully its capacities and its prob- lems. For the small manufacturer the metal indus- tries far more important factor the defense program than realizes or, the present time, some others realize. His adaptability and speed getting his plant into production war goods during the next six months will help keep open for industry the door free, voluntary cooperation with the gov- ernment. The extent which the potential reservoir man hours and machine hours small plants used before the end 1941 may considered vital. THE IRON AGE, January 30, 1941—33 PROGRESS PURCHASING TOLERANCES LABOR | | | New Air Gage for Long Bores barrel checking with con- ventional gages requires high degree skill the part the operator order maintain acceptable standards precision. effort eliminate this troublesome human equation, maintain maximum precision standards consistently and mate- rially increase the speed not only gun barrel inspection but all relatively inaccessible internal di- ameter checking, the Sheffield Gage Corp. has developed the Preci- sionaire, flow type air gage—as contrasted the pressure type gage. The latter operates the principle varying air pressures during the gaging operation, while the flow type instrument registers variations velocity volume air constant pressure flowing during the gaging operation. Compressed air from the regular plant supply the actuating medi- and always held con- stant pressure the construction the gage assembly. The volume and velocity air flowing any given instant the gaging oper- ation depends only the clearance between the gaging nose and the surface the bore being gaged. The greater this clearance, the greater the volume and the higher the velocity. The nose comes several forms. Essentially cylindrical plug having central air channel which terminates one more jets the side the cylinder just back its forward end. Where desired check the average diameter circum- ference instead the actual di- ameter given point, for example thin-walled bushing, the air jets the nose terminate annular groove. Variations velocity flow are measured indicator float free move vertically inside indi- cator tube response the veloc- ity air flowing around it. The float reacts instantly changes velocity and there lag nor pumping effect, regardless the distance between the recording in- strument and the part being gaged. Consequently the gaging nose may placed the end long 34—THE IRON AGE, January 30, 194! ARIATIONS the flow air constant pressure the operating principle the Precisionaire gage for measur- ing gun bores. The special nose pieces are flexibly attached long handles which are con- nected hose indicator unit. ° ° ° length flexible tubing without affecting the accuracy the read- ing. The instrument comparator type and must calibrated against minimum and maximum size mas- ter rings. With pressure on, minimum master ring over the gage nose and air pres- sure adjusted that the indi- cator float will rise point just above the bottom the trans- parent indicator tube. sliding marker set opposite this point. second sliding marker used mark the float position when the maximum master ring tuted for the minimum. The length tube between the two markers represents the difference diam- eter between the two master rings and hence the selected tolerance the work being gaged. This length tube can calibrated the adjacent scale any number equal divisions. Any practical de- gree magnification available merely changing the size and weight the indicator float. The Precisionaire made two models. Model constructed that may presented the work being gaged, while with model parts light enough handle easily are presented the gage. Model applicable heavier, poorly balanced work parts and those that must gaged while still the boring machine. Its gaging nose connected the recording apparatus flexible tubing. For gun bore gaging Model instrument used, with special nose flexibly carried the end tubular handle long enough reach through the bore. The flexi- ble connection between nose and handle eliminates errors that might caused misalinement the handle. The nose actually centers itself. operation, the inspector passes this gage nose through the unrifled bore one continuous pass, watching the position the indicator float does so. When checking for out-of-round con- dition, the inspector turns the nose the gage the bore given point. After the rifling operation sec- ond gaging nose used check the diameter the rifling grooves themselves. The jets this nose terminate bosses raised beyond the regular surface the nose cylinder. These bosses extend into the rifling grooves. The rifling nose inserted the bore with the raised bosses register with two opposite rifling grooves. passed through the bore following these grooves. This operation repeated using each pair grooves turn until all have been checked. can seen the instrument uses hard gaging points and consequently well suited for in- specting such parts artillery re- coil cylinders, the interior finish which must not marred. fact, the gaging nose may equipped with bronze silver rings further protection against surface damage. | Army Air Corps pursuit planes. These are Seversky P-35's. Stainless Steel Aircraft ° Research Staff, Allegheny Ludlum Steel Corp., Brackenridge, Pa., ° ° ° aircraft builders are reluctant use stainless steel extensively, construction material, partly because understandable disinclination change manufacturing methods and partly because the characteristics the metal are not fully understood appreciated. However, under the pressure war-time demands, stainless construction going take spurt—already one newcomer the aviation industry laying out plans start stainless wing con- struction for war planes, and the expectation that another full-fledged plant soon will announced. This article probably the most sensible analysis ever published the problems involved applying stainless aircraft construc- tion—it also very ably sets forth the physical attributes stainless steel and emphasizes the changes specifications necessary serve the airplane industry satisfactorily. Furthermore, some the physical data herein have hitherto not been LUMINUM and its alloys ac- count for about per cent the materials used the construction airplanes. And, the present time not more than per cent the material used airplane construction therefore, consider such points where stainless steel now used, the properties that material will have have order equal aluminum alloys, stainless steel now available for airplane construc- tion, and what changes specifi- cations will necessary serve the airplane torily. When the uses which stainless steel put airplane construction are considered, becomes apparent that most the applications are ones which not economical use any other metal. These uses include applications where resis- tance heat necessary—such exhaust manifolds and all metal from the fire wall forward. Other uses include such parts bomb racks, where combination re- sistance abrasion well cor- rosion desirable. Stainless steel has been used only very limited extent struc- tural members that have carry stresses. Aluminum alloys are used almost exclusively for this purpose. The extensive use aluminum has continued because its well known strength-weight ratio, be- cause the experience the air- plane people with its properties, be- cause lack the proper facilities such dies and presses for forming stainless steel, and be- cause lack knowledge the properties stainless steels. Much has been written and said THE IRON AGE, January 30, » 4 in- re- ct, ace about the corrosion and heat re- sistant properties austenitic stainless steels. However, relatively little has been said about their mechanical properties spite the fact that variety very re- markable and useful properties can obtained. Changes chemical composition produce considerable differences the mechanical prop- erties that within the range compositions austenitic stain- less steels that can obtained commercially possible obtain variety different type alloys. These range from relatively soft metal with low rate work hard- ening that lends itself readily spinning operations, alloys that are slightly harder and have rate work hardening that make them well suited drawing, and finally alloys that have high rate work hardening that can cold rolled very high tensile strengths and still have sufficient ductility allow strip and sheet formed into structural shapes. The primary requisite necessary order obtain alloy with the desired mechanical properties control the composition that austenitic structure obtained that has the necessary tendency transform into ferrite. For ex- ample, with approximately per cent chromium the addition ap- proximately per cent nickel pro- duces austenitic structure that room temperature completely stable without any tendency transform into ferrite. When such alloy cold worked, the rate work hardening relatively low and the increase hardness that produced the cold working the austenite. the nickel con- tent the alloy lowered per cent with the chromium con- tent remaining approximately per cent, austenitic structure obtained which room tempera- ture less stable than the higher nickel alloy and there exists ten- dency for some the austenite transform ferrite. -This change sluggish and will not occur until the metal cold worked. During cold working this alloy would ex- hibit higher rate work harden- ing than the per alloy because addition the hardness obtained through cold de- formation the metal, additional hardness appears derived from the transformation some the austenite into ferrite. alloys with successively lower nickel contents are examined will 36—THE IRON AGE, January 30, found that the rate work hard- ening gradually increases re- sult increased instability the austenite which results increased amount transforming into ferrite during cold working. the nickel con- tent made too low, then the austenite becomes very unstable and such large quantities transform into ferrite that brittle useless alloys are obtained. seems possible that lack information this type the air- mechanical strength that can ob- tained with aluminum alloys are tensile strength approximately 62,000 per sq. in. and yield strength approximately 42,000 lb. per sq. in. When taken into account that given volume stainless steel 2.83 times heavy the same volume alumi- num alloy, evident that order have good strength- weight ratio, stainless steel must have yield strength least 119,000 per sq. in. and tensile TABLE Comparison Aluminum and Stainless Steel Density 18-8 Stainless Ratio Density Duralumin Density 18-8 Stainless Comparison Mechanical Properties Yield Strength, Lbs. Hardened Duralumin sq. in. cross- 42,000 Hardened Duralumin (with 2.83 sq. in. cross- 119,000 Cold rolled stainless steel with sq. in. cross- 7.95 2.83 2.8 Deflection Tensile Per Cent Modulus Yield Strength, elongation Elasticity, Strength, Lbs. In2 In. Lb. Per Sq. In. Inches Per In. 62,000 10,300,000 0.00607 175,400 10,300,000 0.00607 145,000 27,000,000 0.0064 craft manufacturers and the result- ing failure obtain composition best suited particular applica- tion may have contributed the fact that stainless steel used such slight extent the manu- facture airplanes. Required Characteristics The major characteristics considered connection with metal used the aircraft in- dustry are: its strength-weight ra- tio, its forming properties, and its weldability. With regard its weldability, the ease with which stainless steel can resistance welded im- portant point its favor. interesting compare aluminum and stainless steel from the point view their strength-weight ratios. (See Table I.) shown the table, the den- sity Duralumin approximate- 2.8 while that 18-8 about 7.95. Thus the ratio the den- sity stainless steel that Duralumin 2.83 The best strength least 175,460 per sq. in. For example, sq. in. section stainless steel given 2.83 sq. in. section Duralumin the same length. order have the weight-strength ratio, the piece stainless steel would have withstand 119,000 before arriving its yield strength because this the stress which its hardened condition would its yield strength. Since Dura- lumin has modulus elasticity approximately 10,300,000 Ib. per sq. in. and stainless steel has modulus elasticity approximately 27,- 000,000 Ib. per sq. in., the bar Duralumin just described would deflect 0.00607 in. per inch yield strength 119,000 total load 2.83 sq. in. cross-section, while the bar stainless steel just described would deflect approxi- mately the same yield strength section. other words, there would almost difference the de- | flection produced given stress. The point view has been ex- pressed that would change from aluminum stainless steel for airplane parts that have carry stress, because order maintain the same strength-weight ratio the thickness the part made out stainless steel would have have approxi- mately third the thickness that had when made out aluminum. pointed out that rigidity structure important the strength-weight ratio, and that al- though the requirements the strength-weight ratio are met using thinner gages stronger stainless steel, the rigidity under compression requirements may not satisfactorily met because this not function much the dependent the ratio the length the section the thickness the section, other words, slen- derness ratio. The above line reasoning true only parts designed made out aluminum alloys are made out stainless steel without any redesigning take into ac- count the properties stainless steel. true that with flat piece Duralumin and flat piece stainless steel each having the same length but varying cross- section have the same weight-strength ratio, greater resistance buckling un- der compression because greater cross-section area. How- ever, this advantage could easily overcome and the resistance buckling can made vary will simply corrugating the flat piece stainless steel. This similar what will have done order use stainless steel advantageously the construction aircraft. The airplane industry has grown using aluminum, and during this growth has naturally adopted de- signs that are best suited alu- minum. Naturally these designs are not suitable for stainless steel and new ones will have worked out for it. structural member, resistance buckling not prop- erty the metal being used but property the shape the section into which the metal formed. Under most conditions would rather difficult persuade company change its designs and Machining aluminum wing member the plant Bell Aircraft. methods fabrication order use new material. However, this case change has made the airplane industry order meet the demands the defense program. order meet these de- mands the manufacture planes must put mass pro- duction basis. Material must used that available sufficiently large quantities and that can handled mass production meth- ods. Since, time like this, possible that least part the large proportion aluminum and its alloys now used will have replaced another metal, will THE IRON AGE, January 30, tal ist . Ss- | TABLE Mechanical Properties Stainless Steel Strip Alloy and Treatment Yield Tensile Per Cent Strength, Strength, Elongation Lb. Per Sq. In. Lb. Per Sq. In. In. rolled stainless steel 19-9 strip, with sq. in. Cold rolled stainless 18-8 strip, with sq. in. cross-section) .................. Cold rolled stainless (0.15 18.00 Cr, 7.0 Ni, 0.50 strip, with sq. in. cross-section) Minimum strength that stainless steel must have order compete with aluminum ............... 129,000 145,000 interesting consider what stainless steel has offer this respect. the basis past experience, cold rolled stainless steel strip that has elongation approximately per cent, the 2-in. gage length the standard tensile test, should have sufficient ductility make the bends that would expected the forming such parts angles and I-beams that are used struc- tural members. So, taking this fig- ure per cent elongation the standard 2-in. gage length tensile interest consider what mechanical properties can ob- tained with stainless steel. (See Table 302 Types Not Satisfactory With 0.11 carbon, and approxi- mately chromium and per cent nickel, the proper cold rolling, stainless strip can obtained that together with per cent elonga- tion has yield strength 129,000 per sq. in., and tensile strength 145,000 lb. per sq. in. With 0.10 carbon and approximately chro- mium and per cent nickel, cold rolled strip can obtained with elongation per cent, yield strength 140,000 per sq. in. and tensile strength 160,000 Ib. per sq. in. This range analyses from per cent chromium and per cent nickel represents the compositions that would most likely obtained when ordering regular 18-8 under Type 302 specifications. can seen that the properties that can ob- tained with these alloys are not good enough compete with alu- minum the basis the weight- strength ratio. was pointed out previously that order compete would have have yield strength approximately 119,000 lb. per sq. in., and tensile strength 175,- 000 Ib. per sq. in. Thus, the regular Type 18-8 slightly better than Duralumin when the yield strength basis but falls below Duralumin when tensile strength considered. Most the 17-7 Type 301 stain- less steel that made has had suffi- cient manganese added that the effect the combined nickel and manganese content such that alloy with properties very sim- ilar those described for 18-8 and 19-9 obtained. However, the composition closely controlled that the nickel content falls between 7.0-7.2 per cent, the chromium content 17-18 per cent, the carbon content 0.13- 0.15 per cent with the manganese content close 0.50 per cent, cold rolled strip and sheets can ob- tained that have yield strength 170,000 per sq. in., strength 200,000 per in., with per cent elongation. (See Table III.) When this compared with the previously stated figures for Duralumin, evident that this stainless steel has tensile strength per cent greater and TABLE Compositions With Which High Mechanical Properties Can Obtained Carbon, Chromium, Nickel, Per Cent Per Cent Per Cent Per Cent 0.10—0.12 0.50—0.70 17.90—18.25 17.00—17.40 7.0 —7.2 0.50—0.70 38—THE IRON AGE, January 30, greater than Duralumin when weights the two alloys are com- pared strength-weight basis. the chromium content the above composition limits close per cent, then alloys that have the same desirable prop- erties can produced that contain 0.10-0.12 per cent carbon. order facilitate the solution car- bides during annealing processes prior cold rolling, such carbon contents are necessary. pos- sible have other variations composition within the limits the present Type 301 analysis and still maintain the high mechanical properties stated above. the car- bon content 0.10 0.12 per cent and the chromium content close per cent, the nickel content must about 7.5 per cent, approxi- mately per cent manganese must present with 7.0 7.2 per cent nickel. The only requirement chemical composition that the austenitic structure with the proper tendency transform into ferrite. obvious that the above com- position limits would difficult meet commercial production. However, these are the composition limits that must met the above mentioned desirable properties are chemical specification mini- mum per cent nickel still met. Investigations that have contin- ued over period number years the Allegheny-Ludlum re- search laboratory have shown that relatively wide range composi- tions exists with nickel contents less than per cent, which have the same desirable mechanical prop- erties described above. New Compositions Developed The narrow limits composi- tions just described, lie upper edge this relatively wide range compositions. The wide range existing nickel contents less than per cent has apparently ent time, because the incorrect assumption that more than per cent nickel necessary order produce austenitic structure show that alloys falling the range compositions 0.09-0.13 carbon, 0.50-0.70 manganese, 18-19 chro- mium and 6.25-7.0 nickel have the same high mechanical properties described above after cold rolling. | | | | i] | d | | | | | | | | | | example the mechanical properties that can obtained with alloy this range com- positions shown the data Table IV, obtained from alloy containing 0.11-0.12 carbon, 18.55 chromium, 6.84 nickel, and 0.50 manganese. has been found Allegheny- Ludlum that certain ranges composition changes the concen- tration chromium, the stability the austenite with respect its tendency transform into ferrite was effected manner that contrary the relationship gen- erally believed true. has been generally accepted creasing the makes the austenite However, the alloys containing from approximately 5.5 7.5 per cent nickel and chromium contents the range from per cent, increasing the chromium con- tent produced alloy that ap- peared have more stable austen- ite, when judged the basis work hardening and mechanical properties. (See Table V.)