The Iron Age 1936-10-15: Vol 138 Iss 16

Compact and rugged. accuracy without chatter. setting cambering attachment integral part any desired amount crowning concaving. Direct motor driven wheel. V-belt driven. ~ . hes te, Before you leap the conclusion that your indicating the true temperature, invite you look into the matter your Lead Wire. using Chromel-Alumel couples, but hook them with so-called leads, you are apt have serious Where these leads join the you have thermo-electric junction, and the that junction gets, the greater the possibility But you avoid all this merely using Chromel-Alumel leads that have the same compos: tion your Chromel-Alumel couples. However generated. These statements are well sustained such companies Ford, General Motors, and who use nothing but Chromel-Alumel with Chromel-Alumel couples, because they want accuracy. temperature accuracy vital you, send for Hoskins Manufacturing Co, Detroit, Michigan. TC 2—THE IRON AGE, October 15, 1936 THE IRON AGE, published every Thursday the CO., (INC.), Chestnut Philadelphia, Entered second class 1932, the Post Office Philadelphia under Act March 1879. $6.00 year S., Canada $8.50, Foreign $12.00. 138, No. 3 | i} i CHESTNUT AND 56TH STREETS, PHILADELPHIA, PA. Sales Offices 239 WEST 39TH STREET with have hotter ity using hot IRON AGE wishes express its appre- tained ciation Climax Molybdenum Co. for furnishing and permitting the use the photo- reproduced this issue pages 47, and 199. The photo page was furnished Margaret Bourke-White, that want page 145 was supplied Richard Dooner, Philadelphia, and the one reproduced page was furnished through the courtesy Lin- coln Electric Co. Owned and Published CHILTON COMPANY (Incorporated) Executive and Publication Offices, Chestnut and 56th Sts., Philadelphia, Pa. MUSSELMAN, President FRITZ Executive Vice-President HILDRETH. GEORGE EVERIT TERHUNE, WILLIAM BARBER, Treasurer JOHN BLAIR Secretary matter No, 16, NEW YORK, FRITZ FRANK President J. H. VAN DEVENTER Editor c. E. WRIGHT A. Il. FINDLEY Managing Editor Editor Emeritus Machinery Editor Art Editor Metallurgical Associate Editors Resident District Editors Washington Chicago Cleveland Detroit Pittsburgh Editorial Correspondents London, England Cincinnati Boston Hamburg, Germany Milwaukee San Francisco SANDERSON ASA ROUNDTREE, JR. LERoy ALLISON Toronto, Ontario Birmingham, Ala. Newark, St. Louis Buffalo Con 15, 1936 Direct Rolled Aluminum Direct Rolling Pictorial Insert Electric Heat Treating Wire What's New the Exposition? Furnaces and Refractories Section Nitriding Welding and Cutting Section Heat Effect Welding Metals Section .... Springs Stainless Steel Review Copper Alloys 114 Metal Cleaning and Finishing Section 145 Progress Rust Proofing 147 Metal Working Machinery Section Use Turning Tools 163 First Aid Metal Workers Section 199 Tips for Metal Workers Automotive Industry 220 Statistics Metal Working Activity Washington News 226 NEWS CONTENTS 238 Products Advertised 295 Index Advertisers 320 Copyright 1936 Chilton Company (Inc.) BAUR, General Advertising Manager DIX, Manager Reader Service A1DVERTISING STAFF Member, Associated Business Papers Emerson Findley, 621 Union Cleveland Member, Audit Bureau of Circulations Indexed the Industrial Arts Index. Herman, Chilton Chestnut 56th Sts., Philadelphia, Pa. H. K. Hottenstein, 802 Otis Bidg., Chicago Peirce Lewis, 7310 Woodward Ave., Detroit Published every Thursday. Subscrip- tion Price: United States and Pos- sessions. Mexico, Cuba. $6.00: Can- ada, $8.50, including duty; Foreign C. H. Ober, 239 W. 39th St., New York $12.00 a year. Single copy. 25 cents W. B. Robinson, 428 Park Bidg., Pittsburgh Cable Address, Warren, Box 81, Hartford, Conn * Rony) As i — — = = —— — — — ly 8. f rs VOICE For quick, convenient, economical service Ryerson Stocks Include: Beams and Heavy Structurals steel and allied lines, phone, wire write the nearest Ryerson Channels, Angles, Tees and Rails, Splices, Spikes, Bolts, Etc. plant. Each plant organized make quick delivery all Plates—Sheets Strip Steel, Flat Wire, Etc. Stainless Steel Hot Rolled Bars—Hoops and Bands Cold Finished Shafting and Screw Stock orders, large small. The material stock. Special order and dispatch systems—experienced steel men with modern equipment and every shipping facility your assurance Extra Wide Cold Finished Flats Alloy Steels—Tool Steels against delay. Heat Treated Alloy Steel Bars Boiler Tubes and Fittings Welding Rod—Mechanical Tubing The Ryerson Stock List describes the complete range mmediat ipm not have Reinforcing Bars products carried for ate Shipment. you the current issue, will glad send it. RYE 22—THE IRON AGE, October 15, 1936 | | | | ' e : Metal men from all over the S., from nearly every foreign country, poured into last year’s National Metal Congress Exposition. 17,344 registered and proved their own satisfaction that this great Metal Show the most important event the year. They came with thirst for metal knowledge. They went learned first- away with the latest news metal progress. learned technical sessions addressed leaders the metal learned conversation with new friends and old. This year, five great national Societies are cooperating present the eighteenth annual National Metal Congress Exposition Cleveland’s huge Public Auditorium. Technical programs are the most comprehensive, the most complete the history the Metal Congress. More than 175 metal experts have cooperated prepare 107 talks deal- ing with production, selection, fabrication, testing, inspection, PUBLIC AUDITORIUM THEY PUT THE STAMP APPROVAL LAST YEAR’S METAL SHOW treatment, welding and application all kinds metals. And the Congress only part the attraction. Another part the Metal Exposition where two hundred manufactur- ers will present least 24,273 items with regard materials, methods and equipment used the metal industry. Many exhibits will actual operation. You may compare and consider, one time and one place, the equipment which you are particularly interested. Rest assured, you will see the greatest Metal Show earth. You will have opportunity exchange ideas with lead- ers your chance renew old friendships. The 17,344 metal men who visited last year’s Show will tell you this the most important metal event the year— and 17,344 wrong. The Show opens Monday the 19th. Write wire for hotel reservations now—be hand for the first day. ENGINEER SOCIETY MECHANICAL ENGINEERS AMERICAN WELDING SOCIETY THE WIR very happy extend the readers THE AGE most cordial welcome attend the National Metal Congress and Exposition held Cleveland, Oct. 23, 1936. The Congress, sponsored the American Society for Metals, cooperation with the American Institute Mining and Metallurgical Engineers, American Society Mechanical Engineers, and American Welding Society (holding simultaneous but separate sessions) will the most important meeting metals held for many years. outstanding feature the American Society for Metals technical sessions the past has been the sym- posiums, particularly those nitriding and grain size, and, this year, addition other very important papers the most famous metallurgists, two-day symposium will held the working metals. series educational lectures will again presented during the Congress, the title this year being, Phys- ical Testing Another outstanding paper presented the American Society for Metals the Campbell Memorial Lecture, "High Speed Steel Carbide Segregate and Grain Size." The exposition, which this year will have greater variety exhibits than ever before, will one the largest the history the Society. Prac- tically every product, process and type equipment used the metal industry will displayed the Public Auditorium, where the exposition will held. take pleasure extending all the readers THE IRON AGE sincere and cordial invitation at- tend the convention and exposition. ARCHER President, American Society for Metals technical meetings held the societies participat- ing the National Metal Congress are particular value industry. The forthcoming gathering Cleve- land will bring together groups interested progress metals and their application machines and equipment. The great handicap progress the often slow intro- duction new developments into practice, but previous years, the Metal Congress will aid tremendously overcoming this handicap. The participation this year the American Society Mechanical Engineers espe- cially significant that will join with the American Welding Society symposium that will bring engi- neers series papers and discussions which will give them useful welding practice. readers THE AGE suggest that they attend the sym- posium, and examine all the other timely scientific papers being sponsored the Society Mechanical Engineers. WILLIAM BATT, President, American Mechanical Engineers J ‘ 4 § 4 } — : a _ | q kl (t— 7 y? | | privilege, indeed, welcome the National Metal Congress the members and friends the vari- ous associations that are meeting Cleveland Oct. 19-23. The Metals Divisions the American Institute Min- ing and Metallurgical Engineers—the and Steel Divi- sion and the Institute Metals Division—are, past years, holding their fall meetings conjunction with the National Metal Congress and Exposition. The technical sessions the Congress and the presentation the outstanding recent scientific and engineering accomplishments metallurgical fields furnish added ac- celeration the steadily increasing activity, efficiency, and accomplishments the metals industries. The divi- sions the American Institute Mining and Metallurgical Engineers primarily interested other phases the mineral industries, the mining and processing metal- and non-metallic minerals, coal and petroleum, are also keenly interested advances the technology and engineering applications metals and alloys, many their problems have profited from such advances the past and will continue the future. JOHN LOVEJOY, President, American Institute Mining and Metallurgical Engineers growing interest welding and flame cutting amply demonstrated the fact that the space occupied the various exhibitors who will show all the latest developments will, this year, far larger than any previous convention. the relatively short time that welding and cutting have been recognized the regulatory bodies remarkable progress has been made. For example, there are now use, and all with excellent service records, over 4000 pres- sure vessels constructed accordance with the highest requirements the American Society Mechanical Engineers Code, and the number buildings com- pletely partly fabricated means welding and flame machining rapidly increasing. The excellent service being obtained with thousands miles pipe, much operating high pressures, joined welding brazing, should sufficient satisfy even the doubtful the merits this method fabrication. The executive and engineer will find much interest the various technical papers dealing with the fabrica- tion the newer alloy steels and viewing demonstra- tions the latest developments welding and cutting and the equipment used. The architect and heating engineer together with the plumber and pipe fitter will learn why the old threaded joint rapidly giving way the more modern welded brazed joint. And they will see how easily some the modern joints can made. The two sessions fundamental research, together with the evening sessions given over the university re- search work will offer opportunities for the metallurgist and test engineer that should not missed. JOHN CROWE, President, American Welding Society Pe. 4 ap 4 | q | | | | ry MODERN ists have long been di- vided into two schools thought. One group holds firmly the belief that pe- riods depression should coun- terbalanced means individual retrenchment and concentration energy established and reliable activities. opposition, another group considers the comparative inactivity during depressive periods prime opportunity for dynamic research leading the develop- ment better and cheaper manu- facturing processes. Thus, full and IRON AGE, October 15, 1936 LIPPERT Metallurgical Editor, The Age profitable advantage can taken subsequent boom periods. Crown Cork Seal Co., Balti- more, definitely belongs the lat- ter classification, mainly McManus, president. three previous occasions, Mr. McManus has initiated new proc- esses the economic cycle was swinging downward. And, for the fourth time, most ambitious schedule development and expan- sion was started over three years ago, time when many other industries gloom. Mr. McManus somewhat chagrined the current instance, however, for there has been slight the time cycle. The depression over his opin- ion, whereas his new developments production fully for six more months. Within the six months, the enor- mous new 19-acre Crown Can Co. turning out 3,600,000 beer and sani- tary cans daily, with ultimate potential production 7,500,000 cans daily. portion the plant will devoted steel bar- rel fabrication, entirely new line for the Baltimore concern. This alone will increase the company’s plate consumption threefold, from about 1,500,000 yearly to, perhaps, 4,000,000 base boxes. addition, several small independent producers other tions the country quietly bought out, thereby fur- ther increasing Crown Cork Seal Co.’s tin plate requirements the neighborhood 5,000,000 base boxes. This tremendous expansion capacity predicated solely Mr. McManus’ firm conviction that within several years the country’s present can and tin plate capacity will insufficient satisfy the demand for canned beer and other canned products now relegated glass containers. defense its belief, the company points the increasing demand for beer cans, and, addition, the sharply declin- ing percentage beer volume go- ing into kegs. When the Eighteenth Amendment was thrown into the discard, per cent the country’s beer went into kegs whereas this ratio has now dropped per cent. Over the next several years the percentage may drop even fur- ther with concomitant gains for both the bottle and can industries. the per cent beer now containers, cans secured only per cent last year, but Crown Cork Seal Co. confidently expects canned beer enjoy constantly increasing favoritism. This story, however, not based the confidence the Baltimore concern has the future cans. After all, the can expansion natural, albeit very large, growth well-established company which has been making some the country’s cans and most the bot- tle closures since 1892. The really noteworthy fact that one the heaviest buyers rolled aluminum now position supply all its own requirements; and one the steel industry’s most desirable patrons soon expects about one-half self-sufficient. Likewise noteworthy the fact that even now the company production aluminum steel, proprietary product said superior tin plate for many purposes. new alloy also has been developed and may soon introduced the can industry—it will corrosion resistant, and said cheaper and considerably lighter than tin mill black plate. But, even transition from con- producer (and, perhaps, competitor) not unique it- self—the factor that makes this particular case outstanding that self-sufficiency has not tained installing conventional production equipment but predi- cated entirely the development and confidence the revolution- ary Hazelett direct-rolling mill. the past two months over 215,000 lb. aluminum has been direct- rolled one operation from the liquid state, and some this ma- terial has already been marketed consumer more, before the year’s end, the company expects melting The Homely Crown Cork age user; for merely something pry off order secure the contents bottle. Crown Cork Seal Co., how- ever, highly important prod- uct which sells for apiece and consumes about 50,000 tons tin plate and 1,090,000 foil yearly. further cheapen and improve the crown, about $6,000,000 has vested and two revolutionary man- ufacturing processes have been perfected. The formed crown shell (A) fitted with composi- tion cork (B) which protected from the contents the bottle spot aluminum (C). down its own steel scrap, hereto- fore sold back steel mills, and direct-rolling the rate five tons hourly. The steel strip pro- duced will subsequently reduced tin plate gage the five-stand four-high continuous mill pictured the accompanying insert. Pro- visions have been made tin some this steel the company de- sires, but far the greatest per- centage will aluminum coated recently perfected process. sizable quantity this aluminum- coated steel already has been quiet- THE IRON AGE, October 15, 1936—27 placed the market the form screw caps for whiskey bottles. Thus, Crown Cork Seal Co. becomes the first successfully produce aluminum the direct- rolling mill and bids fair become the first turn out steel commer- cially. The company likewise holds the key successful commercial hot-dipping aluminum onto steel. Both these processes have tremen- dous industrial significance, and for this reason their technical aspects will considered the following paragraphs. Worthy first description the direct-rolling mill. Crown Cork Seal Co. and the Aluminum Co. America are sole licensees pro- duce aluminum the Hazelett mill. The latter firm has just com- pleted large modern mill New Kensington, Pa., but started overcome the many in- herent idiosyncrasies the mill which Crown Cork Seal Co. has already mastered through the in- genuity Mathew Schon, general manager the metals department, assisted George Nauss, chief metallurgist. The direct rolling mill for over year has successfully produced many tons brass the Water- bury, Conn., plant the Scovill Mfg. Co., and the material pro- duced amenable deep-drawn consumer products. The only description this installation appeared THE IRON AGE, March 21, 1935, and that article the general operation direct-rolling mills was consid- ered detail. Suffice say, such mill essentially two horizontal rolls, one which equipped with flange that shallow pool molten metal can supported be- tween them. the rolls are sep- arated by, say, in. and are set rotation, not hard visu- alize how some metal constantly frozen each roll, and, the rolls rotate, this frozen metal pressed together and emerges homogeneous and smooth-surfaced emerging strip cast metal strip; for modern mill like that Bal- timore imparts considerable rolling reduction the metal after has been chill cast the two roll sur- faces. addition, the strip has just recently been improved con- siderably drawing from the mill under extremely high ten- sion. Thus, metal produced the di- > B * if. \ : q ute ~ rect-rolling mill undergoes what essentially casting-rolling-ex- trusion cycle. Aluminum Peculiarities Overcome Unfortunately, only few the experiences gained Scovill the production brass could transferred mill for aluminum. This resulted from the inherent peculiarities the metal aluminum, which even conventional ingot-rolling prac- tice one the most exasperating and “ticklish” metals handle. Molten aluminum very sensitive temperature changes and oxi- dizes very rapidly. addition, necessary coat the steel rolls with aluminum before satisfactory rolling results, and, occasionally, requires weeks patient effort secure proper aluminum coat- ing the rolls. But, the other hand, methods are being developed which cut this time few hours. This necessity properly coating the rolls common the direct- IRON AGE, October 15, 1936 rolling mill and conventional hot and cold mills for reducing ingots. Mr. Schon and his associates devoted months work experi- menting with various roll materials which aluminum would not stick. But material was found which fulfilled this requirement and the same time was desirable phys- ically and economically. Other months were spent experiment- ing with various nozzle designs for properly distributing the metal be- tween the rolls, variations the WELVE months experimental work has ironed out many the aluminum di- ties. The ragged torn, minum above was the typical product first produced the mill last November. Be- low are duced today—the strip has uniform matte ish, gage variations are far under one- thousandth, the edge smooth and scrap loss nil. water-spray practice for cooling the rolls were studied, and even be- came necessary develop suitable alloys for the metal distributors which would have the ultimate re- sistance the corrosive and ero- sive action molten aluminum. All this experimental effort was spread over about one year’s time. There can doubt but what the final accomplishment justified the labor involved. For consider that the first metal turned out had extreme gage variations, surface, was inclined tear and seldom ran over several feet with- out getting ragged stopping al- together. Now turn the insert with this article and examine photo pictured the mill steadily turning out about the best looking aluminum strip this writer has ever seen. Notice the clean edges and the extreme smoothness the surface. The metal being rolled 24-in. wide. The usual edge thickness 0.120 in., and the cen- ter deliberately crowned slightly 0.122 in. Gage variations are small ignored, and the completed coil measures about 500 ft. length. This one small mill tially very large production. takes about min. roll 1800 aluminum the width and gage just mentioned. There not one pound scrap loss the entire run, and the investment and oper- ating cost producing metal con- tinuously extremely low when compared with conventional duction procedures. Crown Cork Seal Co. has the past pur- chased large quantities foreign aluminum, and, even when 4c. per duty paid, the delivery price Baltimore estimated being Thus conceivable that even now aluminum could rolled from this foreign metal into continuous strip in. wide and 0.120 in. thick and ready for im- mediate fabrication price com- petitive with domestic aluminum pigs. This last statement implies that the aluminum just the condition comes from the direct-rolling mill suitable for fabrication. And such the case. The surface has pleasing matte finish, and, phys- ically, the direct-rolled metal spects ordinary aluminum hot- rolled from ingots. the metal leaves the mill has half-hard temper—the about 13,000 15,000 per sq. about 7000 lb. per sq. for ordi- nary cast aluminum, and 9,000-10,- 000 lb. per sq. in. for ordinary full- annealed hot-rolled aluminum. tility tests are highly satisfactory, and Brinell hardness determina- tions (500 kg. load) taken equal intervals across the width the strip run the following typical fashion—29, 31, 31, 29, 30, 31, 31, 30, 33, 30, 28, 31, 30, 30, 30, | 30, 28, 28, 31, and 31. Thus there physical reason prevent aluminum from leaving the direct- rolling mill and immediately enter- ing punch press for fabrication into variety sheet metal prod- ucts. Under the microscope the direct- rolled aluminum naturally does not have the appearance cast metal. aluminum direct-rolling mill was suddenly stopped and slug metal froze. When this slug was sectioned and shown here, became obvious that the mill constantly reduc- ing what essentially solid, hot, constantly reforming tapered ingot. The roll positions are sketched in; also shown are the temperature the liquid metal entering the rolls and the tem- perature the strip just leaves. aluminum but just often has bastard structure which has yet not been fully analyzed and which probably originates when some the interior metal being rolled mushy state. Produce Foil But Crown Cork Seal Co. has little use for the size and gage mill. This merely the first step leading ultimate reduction aluminum foil for use “spots” the crown cork. The applica- tion this “spot” shown the drawing page 27, and its func- tion prevent liquids bottles from absorbing the natural taste the cork. The “spots” are quite small and very thin, but, nonetheless, sur- prisingly large amount alumi- num consumed for this purpose bought the Baltimore concern. Foil this type quite costly, being priced the neighborhood per lb. But Crown Cork Seal Co. confident that foil can reduced from direct-rolled metal its own plant price consid- erably lower. accomplish this end consider- able equipment has already been in- stalled. The direct-rolled alumi- num strip will made dead soft the vertical annealer pictured the insert, after which will reduced the continuous cold mill from 0.120 in. 0.040 in. Thence will again annealed, and then passed through large foil mill now being installed. The strip leaves the foil mill 0.002 in. thick, after which will given final anneal, coated with thermo-plastic cement and then punched out into “spots.” should noted that rolled aluminum made into foil with only three anneals and mini- mum rolling. This follows from the fact that the metal very mal- leable and shows marked ability withstand heavy reductions. One foreign foil plant has reduced sev- eral coils and has reported that the final product was definitely superi- foil previously rolled down from ingots. This aluminum foil particularly favorable when compared with the THE IRON AGE, October 15, 1936—29 bes : : : conventional method producing aluminum foil. That is, aluminum usually cast 200 300 slabs about in. thick. Frequently the entire surface scalped, after which the ingots are hot rolled eight ten times down 0.5 in., usually with one intermediate re- heating. These breakdowns then roughing mill and emerge about 0.040 in. thick. intermediate anneals are usually required. Cold finishing units then metal from 0.040 0.010, with four passes and one anneal, after which in. five passes and with two an- neals. apparent, therefore, that this procedure entails considerable scrap loss, requires more time and more individual operations, and, for these reasons, must decidedly more expensive than for similar foil produced metal. successfully Crown Cork Seal Co. making direct-rolled alu- minum for subsequent reduction into foil that will completely self-sufficient, and, quite likely, will have excess production for sale licensees making the “spot” crown. Furthermore, not unlikely that coils will sent European mills making foil and selling abroad, and negotiations are also under way for supplying American unit which does sizable independent business mounted and embossed foil. Still further, the company’s alu- minum position now encour- aging that definite arrangements have been made branch out still another direction. collapsi- ble tube machine has already been installed and others will bought market demand grows. mak- ing products from direct-rolled alu- minum, certain amount scrap ensues, This scrap will stamped into small plugs and drawn into toothpaste tubes, etc. Preliminary experiments have shown the metal admirably suited this operation. the present time Crown Cork Seal Co. uses one electric re- sistance furnace for melting alumi- num. takes several hours melt down 1800-lb. batch cold pigs and only min. pour the charge. Obviously, therefore, the operation necessarily intermit- tent. Inasmuch the Hazelett mill operates best advantage con- stant production, continuous melting unit would economically 30—THE IRON AGE, October 15, 1936 desirable. Such furnace now being designed, and, when placed operation during the turn the year, will permit continuous roll- ing aluminum delayed only roll changes. The experimental work the present direct-rolling mill has dis- closed various refinements which would facilitate the operation. For this reason, second and larger aluminum mill even now being designed and will probably built during the next year. The new unit will probably roll strip 30-in. wide and will have secondary set reduction rolls. That is, the strip leaves the direct-rolling rolls, will immediately pass while hot through another set reducing rolls and will emerge 0.06 in. thick. this way, will not necessary pass the strip through the con- tinuous cold mill. Also, through the use neutral atmosphere and reduction the amount cooling water, anticipated that the metal will have almost mir- ror finish. Action During Rolling mentioned, the liquid-solid aluminum undergoes combination casting, rolling and extruding action passes through the direct rolling mill. Ac- cidentally, better insight was given into this particular phase the operation when once the mill was unavoidably shut down and liquid metal froze between the rolls. This plug metal was removed, sec- tioned and etched and showed the appearance reproduced page 29. The metal which solidified from the molten state shows being quite porous. That metal which froze onto the rolls more dense (as shown the thin line solid metal from each roll) and the start operation which completed further down between the rolls. This cast metal carried along the rolls rotate and encloses certain amount liquid semi-solid metal which rapidly solidifies the metal receives its maximum hot reduction right the nib the rolls. This reducing action accentuated the use tension 25,000 lb. (across the total 24-in. width). The actual rolling pressure during this operation varies 600,000 and 1,800,000 deter- mined Messinger pressure box, and only requires between and hp. turn the rolls. means some clever control work Clark Controller Co. this power available immediately the mill starts. That is, run metal begun, the rolls are kept stationary until pool metal builds between them—then the motor started and the rolls turn immediately speed and full power. And the pool metal grows higher, the control steps the roll speed slightly. this arrangement, metal strip the beginning pour starts out with clean edge and full gage. would indicate that the pool liquid metal between the rolls carried about in. deep. How- ever more shallow pool gen- erally used—about in. above the nib the rolls. For the depth, the liquid metal pool measures about in. across from roll surface roll surface. con- sideration the non-porous section would indicate that considerable portion the metal receives sizable amount hot reduction for travel distance about in. more between the rolls. this reduction which gives the metal one-half hard temper emerges. The temperature the alumi- num enters the pool metal between the rolls about 1250 deg. and just the metal leaves the rolls its temperature close 700 deg. Immediately thereafter water sprayed onto the surface and few feet further the metal cold the touch. With all the factors previously mentioned mind, apparent that there mystery about the operation mill. The rolls are actually reduc- ing what essentially constantly reforming, solid, tapered ingot hot metal. this respect simi- lar the ordinary blooming mill —for slug liquid metal the direct-rolling mill were permitted solidify, could still rolled out into sheet enough power were applied the rolls and the housings stayed one piece. However, rotating the rolls constantly and only permit- ting small amount metal solidify any one instant, the total metal reduction consider- ably lessened, the power require- ments are much lower, impurities constantly float top the pool metal, and strip indefinite 4 all 4 | A q an i ~ example, consi > turn producer, but the perfection the attain self-sufficiency self-sufficiency steel. scope operations face and clean edge leaving the furnace and (2); side view shows direct-rolled alumi 4-high Metamorphosis Consumer example, consider Crown Cork Seal Co., Baltimore, which normally consumer 70,000 tons tin plate and over aluminum foil and bands yearly. This company not the first consumer turn producer, but has won special mention through the perfection the revolutionary direct-rolling mill attain self-sufficiency aluminum, and, probably, partial self-sufficiency steel. these first pictures showing the scope operations Baltimore, note the perfect sur- face and clean edge the continuous aluminum strip coming from the direct-rolling mill (1) in. wide, in. thick and speed ft. per min. Aluminum leaving the furnace and entering between the rolls (2); {3) side view the Hazelett mill; and (4) shows direct-rolled aluminum being reduced foil 4-high cold-rolling mill. 7. 4 & = the vertical softened electric annealer own steel scrap Ited two arc furnaces, is me . the continuous mill (6) and and subsequently poured into the mill. strip reduced tin plate gage then ture the holding furnace (5), direct-rolling then brought correct tempera- length, from one foot one mile more, can secured. Although much the activity Baltimore has been devoted aluminum, enough experimental work has been done with steel make the metals laboratory confi- dent satisfactory commercial op- eration within the next six months. During this period, full range experiments will conducted develop desirable mill characteris- tics and operating technique. With this information hand, new direct-rolling mill for steel will immediately built. has already been determined that di- & rect-rolling with low-carbon steel much more easily accomplished than with high-carbon analyses. important requirement, also, will molten steel which quite clean and comparatively free gas. When these conditions are met, less trouble anticipated with steel than was the case for aluminum. the outset there will necessity coating the rolls and the sticking problem will far less severe. Direct-Rolled Steel Crown Cork Seal Co.’s canning division accumulates considerable scrap each month and there also sizable amount waste involved during the stamp- ing crown corks All this scrap, which has previously been sold the open market, will care for sizable pro- portion the direct-rolling mill requirements. There about 16,- 000 tons the waste material now accumulated Baltimore, and expected that most will have been direct-rolled into strip during the next half year. The scrap, to- agents, will passed through two top-charge naces. batch cold melt practice, these two furnaces are capable when operating steadily and under favorable conditions making six-ton heat every hr. One view the accompanying insert shows the relative location these two batch melting furnaces. Between the furnaces and the Hazelett mill, holding furnace located (the holding furnace actually shown the insert resistance type for oxide coated surface (left), steel just leaves the direct-rolling The middle surface micrograph diame- ters with oblique illumination this same surface after pickling. The micrograph 100 diameters the right shows the excellent fine grain near the surface steel. ° are furnace for steel). The hold- ing furnace will operate duplex- ing practice, i.e., will receive its charge molten form from the two melting units. The holding fur- nace can operated with from 9-ton bath even larger, and its function bring the steel the exact temperature re- quired the direct-rolling mill and feed into the distributor the proper rate. When the op- eration the two are melting fur- naces are staggered and used build supply metal the holding furnace, evident that the direct-rolling mill can turn out strip constant and rapid pace. After the continuous strip leaves the direct-rolling mill, will pass through Wheelabrator unit for removal the film scale adher- ing the surface. Thence, will pass through the continuous cold mill and reduced tin plate gage, after which will soft- ened the vertical electric an- nealer and finally given temper pass the single-stand four-high mill. All this equipment shown the accompanying insert. rolling steel the direct- rolling mill, the speed produc- tion is, oddly enough, considerably higher than for aluminum—about ft. per min. for steel com- pared with ft. per min. for aluminum. For steel, the tempera- ture involved quite bit higher than for aluminum—3000 deg. against 1250 deg. for alumi- num—but the high temperature itself and its supposed attack the roll surfaces not serious problem generally assumed. Furthermore, the actual heat removed from pound liquid steel the rolls very little more than the heat removed from pound liquid aluminum. For the specific heat and the heat fusion for aluminum much higher than for steel. The specific problems more completely studied steel involve the correct way feed the metal, the development suitable spout refractories, and the determination suitable rolling pressures and tensions. Crown Cork Seal Co. the steel leaves the direct-rolling milling will pass immediately through set pinch rolls which will feed the strip into three-high mill for heavy reduction while still hot. (CONCLUDED PAGE 46) THE IRON AGE, October 1936—33 ‘ q | ape tk q i 4 ELECTR new process consists continuously heating wire electrically direct re- sistance and subsequently quenching rising tem- perature alloy having low melting point. The con- trolled heating rate and quenching speed result product possessing higher physical properties than ONE the most out- standing developments metallurgy during past year has been the introduction new process for the heat treatment spring method the plant the Cleve- land Wire Spring Co., Cleveland. The new process and apparatus was developed the writer, and consists heating the wire means passing electric cur- rent through it, and then cooling *Cleveland Electric Co., 34—THE IRON AGE, October 15, 1936 TREAT WIRE could obtained with the conventional methods use today. this first descrip- tion the process, pointed out that there decarburization the wire surface, the equipment very flexible, easy operate and has high thermal effi- ciency and the heating and quenching cycles can con- trolled accurately. the wire through definite temper- ature ranges. Both the rate heating and cooling can con- trolled with and fa- cility difficult equal with other methods. treating apparatus has nected load kw. and ¢a- pable running six strands wire simultaneously with maxi- mum capacity 500 wire heat treated each hour. The wire heat treated fed from reels through tension rolls and through individually controlled TRAUTMAN* contact members, age current applied heat the wire. The temperature increases until the desired quenching point reached just the wire enters quenching bath consisting alloy which has melting The temperature the wire controlled automatically means cell unit, which has optical system designed that the image the heated wire projected cover the cathode the photo-electric cell. This unit operates conjunction with volt- age regulator which holds the tem- perature the wire within de- grees plus minus the desired quenching temperature. The wire then further cooled oil before entering cally heated lead tempering bath which automatically maintained temperature about 800 deg. The electric lead tempering bath has connected load kw. and heated with General Electric Calrod heating units. After passing through the tem- pering bath, the wire again A. cooled liquid bath which also coats the surface with rust in- hibitor, after which the material passes the take-up reels. These reels, which were built the Broden Construction Co., Cleveland, are the standard eight-block type and are driven means constant speed motor through variable speed transmis- The variable speed transmission equipped with tach- ometer, which enables the operator any time determine the wire speed feet per minute. All these steps the operation are depicted the two photos Figs. and which show the stallation operation. Apparatus Flexible The apparatus extremely flex- ible and desired use the machine for lead patenting wire, only necessary raise the temperature the wire and the quenching medium the point re- quired for patenting. this new electrical heating process high temperature lead pots and furnace equipment are elimi- nated, together with their high maintenance costs. Likewise, when annealing wire made stainless steel and other temperatures around 2100 deg. difficulties are encountered reaching such temperature, would the case furnaces where continuous unit for the continuous heat treatment spring wire the electrical resis- tance method. Wire fed from reels through tension rolls heated elec- trically, quenched molten al- loy having low melting point, tempered electrically heated lead pot, coated liquid bath containing rust inhibitor, and coiled take-up reels, these reels being shown the extreme righi. tures are necessarily dependent the life the refractories and ma- terials which enter into their con- struction. According many wire makers, the present methods heat treat- ing wire continuous operation have been inadequate give the control necessary consistently obtain the highest physical proper- ties desired. The usual method heat treating carbon steel wire heat the wire approximately 1550 deg. F., higher, passing through furnace lead pot. Subsequently the wire quenched oil, after which reheated approximately 800 deg. for tem- pering another lead pot. this usual process, the heat transferred the wire from the outside inward, and, before the in- terior has attained temperature desired for quenching, the outside will have attained such tempera- ture, even higher, for ap- preciable period time. This re- growth. Under such heating con- ditions not possible quench the wire the instant has at- tained the desired degree heat throughout its cross-section, inas- much the temperature the wire will have dropped before en- tering the oil quench account the space separating the oil quench from the furnace. practice under such methods, expediency heating demands the use heating medium operating higher temperature than that actually required heat the wire for quenching. Therefore the ex- terior the wire hotter than the interior the moment the ap- plication heat ceases. Moreover, the wire transferred from the heating furnace the quenching bath loses heat from the outer the heating cross-section the instant quenching. With this new process heat- tricity through the wire, even rate heating secured through- out its cross-section. This permits heating rate from three four times faster than that which could obtained former meth- ods furnace heating. The heating cycle illustrated graphically Fig. which shows heating rate 115 deg. per sec. No. gage, 0.60 0.70 carbon, 0.90 manganese wire. This rate may increased 400 deg. per sec., decreased de- sired. Therefore, there ap- THE IRON AGE, October 1936—35 36—THE So — 3.—Time vs. temperature for No. gage, 0.120- in. diameter, 0.60 carbon, ganese spring wire heated electrical resistance 1450 deg. and quenched ris- ing held 425 deg. the fine grain the cross-section wire the left which has been electrically heated and 1650 deg. The coarser grained speci- men the right has been oil quenched from 1550 deg. the con- ventional manner. Both views are diameters. Logarithmic Time Scale IRON AGE, October 15, 1936 preciable grain growth even when overheating the wire several hun- dred degrees beyond the tempera- ture necessary for quenching. Fig. illustrates No. gage, 0.60 0.70 carbon spring wire magnified eight times, showing the fine grain the wire which was heated the electrical resistance method 1650 deg. and quenched alloy 425 deg. F., compared with the same wire 5.—Time vs. temperature curves showing standard curve for No. gage, 0.60 carbon, ganese spring wire. These graphs com- pare the speed quench with oil quenching and air cooling. {500 | | | | \ 5 | 7] | | | | | | Time, sec. 4 ‘ ° ° ° | | | | | | 12 50 —+— + + + + + + ° ° | | | | | | | heated 1550 deg. furnace and quenched oil. The heating rate the wire proportional the current flow, and the temperature the wire enters the alloy quenching bath using any specific current flow will determined the speed which the wire advances and the distance between the advanced electrodes and the quenching bath. heating wire this method the temperature the interior the wire raised rapidly the temperature the outside surface, and controlling the current flow the wire and the speed which the wire advances, the wire will enter the quenching bath ris- ing temperature and exactly the temperature desired. spring wire this new method, the wire quenched slightly above its upper critical point, about 1450 deg. Electrical Heat Balance One the serious problems in- volved the heat treatment spring wire other methods was due the non-uniformity the product obtained. from the fact that the manufac- IG. 2.—Wire from the tension reels passes through clined housing into the hot alloy quenching the right. The wire quenched rising tem- perature the alloy, which has low melting point. ture spring wire, there exist oc- casional flaws such non-metallic inclusions and variations the al- loying elements which, after heat treatment, produce hardened wire which not uniform. the new process, despite such variations, uniform hardening secured, because any increase electrical resistance encountered points having such flaws inclu- sions will increase the temperature that point sufficiently permit satisfactory hardening. Likewise, equalization the quenching temperature secured even though there may varia- tions the size the wire variation the alloying elements. This results from balance existing between the par- allel advancing cross-sections the, wires and the inherent electri- cal characteristics the appa- Different sizes wire can run parallel. For instance, machine capable heat treating six strands No. gage wire, the wire speed being ft. per min,. No. and No. gage wire could substituted repiacing the two No. gage wires. All the wires would attain the same temperature the point quenching, due the electrical balance existing between the con- ducting cross-sections, which va- ries with the square the diam- eter, and the balance the radiat- ing surfaces, which vary with the first power the diameter, that the net heating effect the cur- rent per foot advancing wire the same even though there some variation the sizes wire being heat treated. Referring Fig. which drawn logarithmic time scale, Zone represents austenitic steel. When steel cooled air shown curve marked “air cool- ing,” the cooling curve passes from Zone into Zone where the austenite begins break down and carbides begin form, transfor- mation being completed when the curve has passed into Zone and pearlitic structure formed. Upon faster cooling, such oil THE IRON AGE, October 15, 1936—37 4 : marked “oil quenching,” the curve does not pass into Zone but re- sults incomplete transforma- tion carbide and ferrite, and upon still further cooling the re- maining austenite the steel be- comes martensite the curve passes into Zones and Upon still faster cooling, such alloy quench, the shown the curve marked “alloy quench,” the quenching speed faster than the critical quenching speed the steel, consequently the curve does not pass either through Zone and upon further cooling 100 per cent martensite obtained. straight time scale, the quenching speed No. gage, 0.120 in. diameter, 0.60 0.70 car- bon, 0.90 manganese wire, oil and “alloy” quenches, and, also, the critical quenching speed and the total quenching time. This curve shows the object the al- loy quench, which delay the RIGHT Compar- ing the quenching speed for termined temperature, after which there further slow cooling from this point eliminate any crack- ing quenching strains set the rapid formation martensite. After the wire leaves the alloy quenching bath passes into oil quench where the temperature the wire reduced below the temperature the alloy quench, shown Fig. With this type quench steel wire having maximum Rockwell hardness 66C obtained which has very fine grain and strength from eight ten times that obtainable oil quenching. subsequent tempering for spring purposes, the hardness reheating approximately 800 shown Fig. illustrates 2000 diameters section No. gage Rockwell The photomicrograph the right Fig. No. gage wire 2000 diameters having Rockwell hardness 66C. Table compares the excellent physical properties obtained gage wire heat treated the electrical-resistance process, compared with other methods. bundle No. gage 0.091 in. diameter regular spring wire with the analysis: carbon, 0.63; manga- nese, 0.101; phosphorus, 0.017; sul- phur, 0.022, and silicon, 0.19 was taken from stock and one-half was tempered 1500 deg. F., quenching oil and then drawing lead about 800 deg. The average physical values the wire after heat treatment the above method are designated The other half the bundle was heat treated the electrical direct-resistance method, “alloy” quenched and then drawn lead shows section quench with that for oil quenching. Time vs. tempera- No. gage, 0.60 carbon, 0.90 manganese spring wire. BELOW | Photomi- crographs 2000 diameters spring wire electrically heated and quenched. Note the globular carbides ferrite the speci- and the crinkly mar- tensite the speci- the men right. | | | | + + Time, sec. | about 800 deg. The average treated this manner are desig- nated (2) Table and Fig. The improvement twist, re- duction area, and the higher elastic limit, shown Table j and Fig. all indicate greater treated wire compared with the thy: 38—THE IRON AGE, October 1936 | | | | | | 4 = | | \ | oO. | | | } | | | | | | | | | | | | | | | ~, Breaking Point 000 Elastic Limit 1500 900 ABOVE hardness Rockwell bent itself. This photo eight di- ameters demonstrates the remark- able bending qualities imparted quenching. 500 LEFT 8.—Stress-strain curve show- ing the elastic limit (Johnson) in. diameter wire. 100 120 200 240 280 The wire has excellent finish. The temperature the wire provement physical properties The thermal efficiency the being heat treated can raised ability the wire withstand sharp bends. This particular wire and yet can bent flat itself without fracture. These properties are highly de- sirable the manufacture high grade springs, inasmuch steel springs are usually highly stressed and subjected very severe work- ing conditions. Spring wire now heat treated the electric resistance method the Cleveland Wire Spring Co. The advantages this process are summarized follows: product with higher physical properties and with greater fa- tigue and impact strength ob- There surface decarburi- zation and there absence surface scale. process very high, the ne