The Iron Age 1945-05-03: Vol 155 Iss 18

100 East 42nd St., New York N.Y., U.S.A. President and Editorial Director Manager Vol. 155, No. May 1945 LEONARD Assistant General Manager Editorial JOHNSON, Manager Reader Service and Market Research New Graphitizer for Cast Iron.................. Increasing the Life and Accuracy Lamination Dies Owned and Published CHILTON COMPANY (Incorporated) Features inte Executive Offices News Front osts JOS. HILORETH Vice-President Personals and Obituaries FAHRENDORF Vice-President anc WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary Tank Rocket Launcher Jettisonable 104 WILLIAM Treas. House Bill Limit Sherman Act 106 Member Audit Bureau Circulation Plywood Surplus Solved 112 Industrial Production Increased 116 Mysore Steel Works Expand 118 Warehouse Officers Named 122 sales Member, Associated Business Papers Polish Economic Strength Increased 130 1end Machine Tool Market Developments 136 Nonferrous Metals News and Prices 138-139 Iron and Steel Scrap News and Prices 140-141 Comparisons Prices Week and Year 142 Indexed the Arts Index. Pub- Finished Iron and Steel 144-145 $15 year. Steel Pipe, Tubing, Wire Products, Prices 148-149 Pig Iron and Coke Prices 150-151 Stainless Steel and Ferroalloy Prices 152-153 | | | | | |) I | 1 : i | | | | Though Ryerson steel-from-stock service your company today can’t always complete and fast like it, nevertheless, certain features our service are probably more helpful than ever before. If, for example, some particular item your com- pany needs not available—though our stocks eleven plants are more diversified than any recommend item that willserve. And the recommendation practical—made men with extensive theoretical well JOSEPH RYERSON SON, INC., Steel-Service Plants: Chicago, Milwaukee, Detroit, St. Louis, Cincinnati, Cleveland, Pittsburgh, Philadelphia, Buffalo, New York, Boston. And How They Benefit Your Company Today most cases can still deliver the steel you want, when you want and where you want it. Thus your purchasing executives can concen- trate with Ryerson and know that Ryerson dependability the same always. That all your Ryerson contacts will sincerely interested helping with your steel prob- lems. That all have learned from more than 100 years the steel business your service. your company hasn’t our latest Stock List and Data Book, will you please write our nearest plant. — — way | ESTABLISHED 1855 May 1945 VAN DEVENTER President and Director BAUR Vice-President and General Manager ° Editorial Staff Technical Editor ......... OLIVER Associate Editors WINTERS JACK HIGHT ALBIN JOHN ANTHONY BARMASEL Editorial Assistants SCHIEN DAVIS News and Technical Editors LLOYD Pittsburgh 428 Park POST Chicago DONALD BROWNE EUGENE HARDY Washington National Press Bidg. LLOYD Cleveland 1016 Guardian Bidg. BRAMS Detroit 7310 Woodward Ave. OSGOOD MURDOCK San Francisco 1355 Morket Editorial Correspondents ROBERT Cincinnati DEAN Buffalo FRAZAR Boston HUGH SHARP Milwaukee SANDERSON Toronto, Ont. RAYMOND KAY Los Angeles JOHN McCUNE Birmingham ROY EDMONDS St. Louis JAMES DOUGLAS Seattle Peace Conference Home this written, the delegates the International Security Con- ference are gathering San Francisco. The first step toward its objective permanent peace between nations will peace and good- will among those participating the conference. Without reflecting upon the scenic and other beauties the West Coast difficult understand why some six thousand miles addi- tional travel should imposed upon probably per cent more those attending, through the selection West Coast site. travel said broaden the mind, but large dose sometimes shortens the temper. And good temper prerequisite good-will which the first essential for peace. Seriously, however, the San Francisco conference undoubtedly the most important event that has taken place this world since the begin- ning the Christian Era which was ushered in, you remember, with the salutation: “On earth peace, good-will toward men.” hope and believe that the participants will approach their great responsibility mankind imbued with the realization its overwhelming importance. Second only importance the establishment peace between nations through agreement accept and observe certain principles conduct the necessity establishing peace America. Especially peace between those who are employed and those who employ. Unless can look forward approaching that objective shall simply move from condition external one internal conflict. The approach internal peace exactly similar that for external. First, there must desire for and recognition its necessity. believe that this desire and recognition exist among per cent em- ployers and employed. Second, there must meeting minds concerning fundamentals principles conduct. Eric Johnston the Chamber Com- merce, and the top labor leaders both the AFL and CIO have al- ready gone long way toward taking that important step. Only idealist, course, would believe that either external in- ternal agreements principles conduct would immediately com- pletely eliminate friction between nations individuals caused con- flicting interests. But only bull-headed employer labor leader would hold that the encouragement unnecessary strife through refusal agree anything all would open the door either better world better America. MUNZER MILLER nt, ely ob- ok, 4 Millions are Single Accident Not many months have passed since accident meant little more than some personal loss and tem- porary, but easily adjusted, work schedule. Today, that situation completely changed. Every accident the 9,000,000 that occur annually national liability, affecting, not only the output the injured worker’s shop, but also the production other shops. Yes, single accident “injures” millions —millions other workers who are trying desperately reach maximum war output millions American citizens who are striving retain their American fighting men whe never can have all the equipment and sup- plies they need for Victory long America care- less the home front. Anything you can prevent accidents will real contribution America’s fight for freedom. Remove hazards home, drive carefully, consid- erate others traffic, observe safety rules when work, promote safety and safety programs matter what your position may be. Start today! Think safety, promote safety! Keep more war workers the job for Victory! Tin Plate Track Accessories INLAND STEEL COMPANY South Dearborn Street, Chicago Illinois Sales Offices: Cincinnati Detroit Indianapolis Kansas City Milwaukee New York St. Louis St. Paul grade users the will point syste board been turne March award Front machine tool plant built China after the war. Current reports are that the Giddings Lewis Machine Tool Co. drawing the plans and specifications. General Motors has been authorized proceed with $1,264,000 project for restoration its Southgate Los Angeles plant for assembly and finishing, ready when the automobile go-ahead given. The plant saw both tank and aircraft production during the war. Ford will build $800,000 parts depot Seattle serve outlets Washington and parts Idaho and Oregon. The project part the company's $150,000,000 postwar expansion program. Despite the magnitude estimated Army transportation requirements the west coast embargo civilian shipments prospect the near future. Bethlehem plans revamping its structural mill Lackawanna cost $15,000,000 $20,000,000. The move being used Buffalo against the proposed St. Lawrence Seaway project. Relaxation wartime controls Canada being reversed, following trends this country. Steel, magnesium, and aluminum restrictions had all been lifted prior the present policy reversal. Effects the cancellation the B-24 Liberator production are being felt production centers, B-29 schedules are not being accelerated, although they have not yet reached their peak. B-32 Dominator schedules are being accelerated limited degree. lom. isid- atter note ssories Paul general, there are sufficient new aircraft contracts available for companies who wish stay the aircraft business. Major automotive firms are being moderately successful getting out aircraft work, even critical importance the program. The auto industry does not expect its reconversion problems include that steel supplies. Belief now being expressed that somewhere more than tons steel will available the first quarter after this, the industry expected allocated sufficient start production, and subsequent stocks will enough meet requirements. stainless steel expected for the immediate future period, but the car makers have been told that they will able the use full alloy steels where they desire them for engine parts, rather than the lean alloy grades. This switch expected Likely most specifications will return the SAE standards, although few series, like the 8600 8700 group, have been satisfactory enough many users during the war period that they will probably continue demand. has restored the spot authorization plan full operation part the board's adjustment reduced military demands. Overall munitions cutbacks per cent are expected made within the next few weeks. Supreme Court's ruling that the single basing point system illegal will probably set off price upheaval. FTC, long opponent the basing point system, likely renew its blows the multiple basing point pricing systen. Economic Stabilizer William Davis his new directive board discretionary authority passage fringe wage adjustments has finally been able put through policy urged head WLB but which had been turned down Fred Vinson. The new standards are considerably more flexible than Vinson's directive March which fixed rigid standards such adjustments. Shift differentials hr. for the second shift and hr. for the third shift may awarded WLB continuous industries well vacation [periods such practice common for the area industry. + | Resin Coatings Baked Induction Heating Baked phenolic coatings pipe have demonstrated great resistance corrosion use. The application induction heat- ing the continuous baking resin coated pipe shows commer- cial practicability and many advantages over conventional baking methods. uses induction heating for the curing resin coatings metal are discussed. phenolic and NICOLSON Chemical Engineers, Research Laboratories, Bakelite Corp., New York resin baking finishes for the protection metallic surfaces against corrosion helping solve one industry’s major problems. These baking finishes are thermoset- ting phenolic resin solutions, which upon application and baking, form in- soluble, infusible, dense, glasslike or- ganic coatings. First brought out some years ago for the protection brass beds against tarnish, these coatings today are finding extensive Power source ° use prevention corrosion all types equip- ment ucts ranging from costume jewelry tank cars and machinery. During the current critical shortage corrosion-resistant metals and al- loys, the use substitute metals with baked phenolic resin coatings has proved highly satisfactory. many cases these organic finishes have with- stood corrosion better than the various metallic ceramic materials used the past. The properties these LEFT duction-baking resin- coated pipe. ° ° RIGHT Heating rates for resin- Variable coated pipe. Stand- motor pipe, B.V. 1600 res- coating. Curve continuous period IRON AGE, May 1945 resin coating solution min.; power input 400 watts. Curve oven heating. Ven- tilated oven tem- perature, 395 deg. baked finishes which have made them successful are excellent resistance mineral acids, organic acids, or- ganic solvents, and most inorganic compounds, along with good electrical insulating properties, good abrasion resistance, and thermal resistance 400 deg. During the past few years intensive studies have been made corrosion- resistant coatings for buried pipe both the Bureau Standards* and private companies. Sections pipe were buried for years various Department Commerce, Na- tional Bureau Standards, Research Paper 1446, January, 1942. types corrosive soils, dug the appointed time and examined for cor- rosion. Pipes that had received phenolic resin baking coating with- stood all the tests. Various corrosion- resistant steels, zinc, cop- per, cast iron, etc., that were included Time, minutes jec ye: aff der cons inte: fron whic oven fired outer the were corroded—some having holes inch more diameter. The speci- mens treated with resin baking film, however, were perfect condition. another test, boiler tubes coated with resin baking varnishes were sub- boiling water 212 deg. the outside and heat radiation 675 deg. the inside. After years service the coatings were un- affected; fact, the inside coating was improved appearance, having become denser and result these tests and the demands the Navy for pipe re- sistant the corrosive action salt water, manufacturers have evinced considerable interest economical method for continuously coating pipe, internally and externally, both the factory and the field. Oven baking being actively considered, but pre- liminary considerations indicate that costly. The recommended baking times for conventional baking methods range from min. 275 deg. 400 deg. The common sources heat which are being used commercially are (a) electrically heated circulating air ovens, (b) gas-fired circulating air ovens, (c) infra-red baking units, and (d) combination the regular gas- fired convection-type oven, and infra- red baking. All the above sources heat de- pend upon convection radiation transfer heat the mass being baked. all cases heat forced from the outside, through the resin film the surface the coated piece. The outer film cured first and that next the pipe last. The time bring the object the polymerization RIGHT resin bath. LEFT OATED pipe passing through heating coils. temperature represents large part the total baking cycle. Further- more, the above baking methods not readily lend themselves con- tinuous operation. The application baked resin finish metallic surface involves the following steps: (a) Surface preparation, such sandblasting etching im- prove adhesion between the baked resin film and the mate- rial being coated. (b) Application the resin solu- tion the object means spray coating, slush coating, dip coating, roller coating, brush coating. (c) more air-drying period immediately after the coating has been applied. (d) baking cycle further poly- merize the resin and produce insoluble, film. Use Induction Heating The curing resin coatings metal electrical method—induc- tion heating—offers many interesting possibilities, eliminating some the limitations conventional methods baking coatings. This method has been applied the continuous coating and curing thermosetting phenolic resin pipe and offers consider- able promise. The process involves passing the pipe through tank the coating solution and then through electromagnetic field actuated low-frequency alternating current. The pipe almost instantly brought the desired temperature, and the coating cured within several minutes, depending the reactivity and heat resistance the coating and the power applied. Mathematical formulas for heating rates and power absorbed are complex and frequently little use practi- cal problems. They serve, however, show the relationship between the various factors involved. where power dissipated eddy currents current flowing the primary coil turns the primary coil resistivity the load permeability the load magnetic field frequency For induction heating applications requiring frequencies 10,000 cycles per sec., power generated al- most entirely motor-generator sets. This range frequency satisfac- tory for almost all induction heating applications except for surface harden- ing and the rapid heating very THE IRON AGE, May 1945—47 A é hoisting mechanism, showing coated pipe section leaving the heat- ing coils. small parts. The latter applications require high frequencies which can best supplied vacuum tube oscil- lator. Where lower frequencies can used, however, generator sets are more economical than vacuum tube oscillators, because their lower equipment and maintenance costs. Continuous Pipe Coating The application resin baking coatings iron pipe (as has been mentioned) problem current interest. The use ordinary ovens for baking the coatings slow proc- ess which requires huge oven ca- pacity and much handling the pipe. the use induction heating for baking, the apparatus can made relatively small and simple, and the operation may one which readily lends itself continuous baking process. such setup would provide in- teresting data, bringing out the ad- vantages and limitations induction heating for the curing coatings, small continuous pipe coating unit was installed the laboratory. matic diagram the apparatus given Fig. Since iron was the metal selected for the tests was de- cided use the most readily available source alternating electrical power —namely, ordinary cycle per sec. 220 volt line. preliminary investigation was made using 550 turn coil, in. high, having internal diameter in., TABLE Data Continuous Pipe Coating Property Type coating Viscosity coating solution, KV... Type pipe, standard Power input-coil Curing temperature, deg. F.. Film thickness-mils Good Good coating except end pipe Energy heat pipe curing temperature Energy input coils 48—THE IRON AGE, May 1945 100 165 1.0 0.8 1.0 1.0 0.75 Film badly Excellent saggedand coating, blistered; free from coating defects solution too viscous coating, free from defects per cent second pipe and thermocouple wires, showing the contrast between the un- treated (top) and the pipe. and length standard iron pipe. Thermocouples were peined the pipe inch intervals provide accurate temperature control. The 220-volt, 60-cycle line the coil was metered for volts, amperes, and watts. The pipe was suspended within the coil, kept stationary, and data ob- tained power-time-temperature re- lationships. From curves these data was possible select the proper power input raise the pipe time, and the required power input keep the pipe this temperature dur- the cycle. For continuous operation, two 550 turn coils were used supply energy the pipe. The pipe was raised the curing temperature while the field the first coil and held that temperature while the field the variable speed hoist- ing mechanism was used draw 5-ft. length standard 1%-in. iron from resin coating tank through the heating coils. The thick- ness the resin film could con- cu RUN 250 490 490 400 440 140 200 200 180 200 410 375 375 410 390 coating, free from defects trolled the viscosity the solution used, the rate withdrawal the pipe. suitable space was left between the surface the resin solu- tion and the heating coils allow for drainage and proper air drying. standard phenolic resin baking coat- ing, Bakelite resin baking varnish BV-1600, diluted with ethyl alcohol the desired viscosity, was used for the tests. Using this induction heating tech- nique, resin baking films were formed both the inside and outside surfaces the iron pipe that were fully equiva- lent those obtained standard oven curing. general, the resin- coated pipe was raised from room temperature 375 deg. 400 deg. min. the lower coil, held this temperature for min. the up- per coil, and then allowed cool room temperature. The pipe emerged from the second coil with hard coating, which was further temperature. summary per- tinent data for several runs given Table many applications resin bak- ing finishes, especially where the cor- rosion problem severe, the use multiple, coats has many obvious ad- vantages over single coat job. The application multiple coats, however, involves the problem not overbak- ing the undercoats order provide good fusion between the coats, espe- cially four five baking schedules are required. The excellent tempera- ture control possible with induction heating makes this method very ap- plicable the baking multiple coatings. Any degree cure for given coat can obtained either regulation the power input the rate travel the work. Actual laboratory runs have been made which multiple coatings pipe have been very satisfactorily applied. The advantages induction heat- ing for the resin coatings ABOVE HIS the same panel that the left, show- ing the side coated with Bakelite resin finish. re- tains its original gloss, and the steel plate underneath has not been attacked. pipe may summarized follows: (a) The rate heating carry tem- perature can made rapid desired, and this, well the temperature curing, limited only the properties the coating employed. This decreases cure time compared with corresponding operation. (See Fig. 2.) (b) The time curing temperature function the the heating coil and the rate travel the pipe. sible. (d) The heat generated within the pipe and the resin cured from the sur- face the pipe outward. (In oven heating the outer film surface cured first, and that next the pipe last. This results cured outer film through which the maining solvent must forced order effect full cure.) This should allow the use higher baking temperature and per- the making thicker blister-free coat- gs. (e) thermosetting thermoplastic coating solutions may used. (f) The operations dipping, with- drawal, air drying and curing require only one handling operation. Known methods coating could also applied. (g) Equipment cost for many applica- tions would low compared the cost large baking Induction heating offers excellent means for continuous baking operation which would great advantage many cases. possible that multiple number pipes bun- dle could passed through single coil one time and heated uniformly. (h) Heating efficiencies, based heat re- quired bring the metal tem- perature, divided the energy input the coil, averaged per cent for the ex- perimental unit. Based per kw-hr., LEFT panel was coated one side with resin baking system, then subjected al- ternately for one week gasoline, hot sea water, and moist air. Then this cycle was repeated each week for years. The uncoated side the panel shown here after the years. ton pipe could treated power cost other words ft. 1-in. 2-in. pipe (standard iron) could coated for power cost le. Other Coating Applications The work done induction baking resin film pipe indicates that this method practical and will givé re- sults fully equivalent other meth- ods baking. The method, however, not limited this one application, but could applied any number metal items having baked resin coatings. For example, the metal sheets used make tin cans, and other metal receptacles, are now coated prior forming, then oven baked and formed. This involves spe- cial techniques the application the resin not coat sections that must later soldered. The cans are not first formed and soldered, and then baked, because the oven capacity required would impractical. Using induction baking, however, would possible form and solder the metal sheet, coat the finished can with resin baking solution, then effect the THE IRON AGE, May 1945—49 | - } | | | de to the hat the ist- ron ank on- cure passing the cans moving belt through magnetic field. All all this would result simpler op- eration which would have the added advantage being continuous. Another problem resin baking finishes for pipes the need for port- able baking equipment that could used the field. the experimental work pipe coatings previously de- scribed, low-frequency power source was utilized, which required coil several hundred turns order sup- ply the required flux practical amperage. With high-frequency power source—500 10,000 cycles per coil relatively few turns would required. would pos- sible, therefore, make simple jigs and coils, and, with the aid port- power supply, the resin baking the field. The baking coatings the in- side pipes would especially easy, for, after the application the resin solution, coil could wound about the outside the pipe using insulated flexible cable, and the power applied. For pipes coated the outside, the general method would the same except for the addition insert heat-exchanger tube. The upper, uncoated, was service months. Corrosion thinned the walls, produced holes. The lower section, coated with Bake- lite resin baking finishes, was service months, was practically unaffected. nonmetallic form support the coil and prevent from touching the varnish coating. This type equip- ment would also find use the patch- ing coatings marred assembly. further into the future, may possible cure baking fin- ishes metallic surfaces flat irregular contours focusing source inductive heat from Patent 2,267,001, Toulmin, quency current source limited area the object This type the use high-frequency power—10,000 50,- 000 cycles per sec. higher. pri- mary coil held near the coated metal surface, thereby inducing sufficient current flow within the metal effect baking the coating. With proper conditions the rate heating the metal object could made far great- than that obtained with baking ovens infra-red baking. New Graphitizer for Cast NEW graphitizing inoculant for ladle additions cast iron has been developed the Vanadium Corp. America and being marketed Graphidox No. The alloy, contain- per cent titanium and per cent calcium, said several times effective ferrosilicon chill reduc- duction effectiveness ferrosilicon and Graphidox cast iron contain- ing 3.25 per cent total carbon, 2.00 per cent silicon. Test data from chill block 5/16 in. wide base. Additions melt, per cent 50—THE IRON AGE, May 1945 030 040 050 tion, Fig. for low carbon-equivalent irons. This inoculant* also serves deoxidize the melt and improve the *See “Inoculants Gray Iron,” Rebecca Hall Smith, Iron Ace, March 15, 1945, 58. strength castings (See Fig. 2), breaking dendritic micro- structures. addition the alloy- sile strength cast iron. 45,000 Base carbon equivalent 3.70 0.20 030 040 Graphidox additions, per cent Graphidox additions, ing. effect the inoculant pro- moting the strength castings, developing maximum benefits from alloy additions cast iron. Because contains large percentage silicon, the amount silicon required alloying can reduced the pro- portions shown Fig. 1G. 3—Recommended silicon re- ductions for corresponding Graphi- dox additions cast iron contain- ing approximately 3.15 per cent carbon and 1.60 per cent silicon. ri { ° ° ° pro- ings, ‘ulin from uired pro- ° ° ° GUY SHINGLEDECKER Superintendent, Laminations Division, Allegheny Ludlum Steel Corp. ° ° trical steel laminations has two primary requisites user’s standpoint. These are mag- netic performance and accuracy dimensions. From the standpoint the producer laminations, there are two other factors addition those necessary satisfy the user. These are minimum scrap loss and long die life. Due the high cost die production, die life not only major consideration, but also, due un- certainty, variable factor esti- mating costs for any type produc- tion requiring large numbers lam- inations. While the Allegheny Ludlum Steel Corp., primarily manufacturer position study the men- tioned since happens the only organization which makes laminations from electrical sheet and strip pro- duced its own plant with dies which UCCESSFUL production elec- makes from its own tool steel. has well equipped punch die making single factor provides the key for the ideal production lamina- tions. The right steel with the cor- rect electrical characteristics and Increasing the Life And Accuracy Lamination Dies Experience gained the production electrical steel lamina- tions Allegheny Ludium Steel Corp. has the development dies long and accurate life, the selection suitable steels and blanking practices. stamping qualities essential course, but the quality the steel not the answer the entire prob- lem. per cent applica- tions correct annealing the lamina- tions after stamping essential order obtain the desired electrical characteristics. Correct and carefully controlled annealing often saves the user money permitting the use lower cost steels than otherwise would necessary. While electrical steels are sold the basis maximum core guarantees, determined standard Epstein tests, these tests not tell the full story about the performance laminations when actually put into motors, generators transformers. The original electrical qualities the steels are affected the stamp- ing operations well anneal- ing subsequent the stamping. The state compression into which the laminations are assembled finished equipment and the final state the oxide insulating coating the laminations alsu are variable factors. The end result actual performance determined only properly conducted tests the finished stamp- ings under conditions identical actual use. Steel Selection The first step the production any set laminations the selec- tion the steel. This involves de- ciding not only upon material which, after annealing, will have the desired electrical characteristics, but also the steel that will have satisfactory stamping qualities for pro- duction. Electrical steels are available both sheets and coiled stock. Con- venience handling gives coiled stock definite advantage when fed high speed automatic presses. Be- cause the differences methods complex structure typical sectional four-stage progressive laminations die used Allegheny Steel Corp. for high speed automatic presses. While sectional construction dies calls for exacting workmanship, adds die life and maintenance production permitting quick replacemént parts case failure. THE IRON AGE, May | ited 50,- pri- etal oper the king | | 4 Fig. 2—The die shown Fig. shown here broken down into all its components. rolling, however, sheets and coiled stock the same analysis have dif- ferent magnetic and physical charac- teristics. general, coiled stock has superior qualities sheets when the path the magnetic flux the finished transformer laminations the direction rolling, and poorer charac- teristics than sheets when the path the magnetic flux across the direction rolling, that is, across the strip. This makes coiled stock ideal for wound cores but disadvantage transformer lamina- tions where large part the path the flux across the direction rolling. the other hand, laminations made from coiled stock have better stacking factor. Coiled stock has 3—Slitting accuracy guaranteed within 0.005 in. necessary fabricating scrapless laminations, where the width the strip the width the laminations. This rotary shear slitting electrical sheets widths required for the scrapless and 52—THE IRON AGE, May 1945 laminations. transformer smooth flat surface which makes possible for fabricator stack little more into given space. These opposing factors must taken into consideration selecting the types steel. Punch Clearances Critical The selection good tool steel and the proper design die are the next essential steps the team neces- sary for ideal lamination production. electrical steel, shown the accompanying table. For lowest die costs per pound finished laminations, has been found desirable maintain the following burr inspection limits basis the best die grinding practice: Gage No. Burr Limit, In. 0.002 0.0025 0.003 0.0035 This procedure will result less that the damage die can repaired minimum time. The building such dies obviously cost- ly, but the savings resulting from the ability repair damaged dies makes the initial cost worth while. typical sectional four-stage progressive die for stamping laminations shown Fig. and the many parts going into this die are shown Fig. The production sectional dies re- quires tool department with fine 4—This standard 25-ton press used producing the and type transformer laminations from alloy coils. The die the sec- tional progressive type, using Huron die steel all cutting edges. This die steel hardened 62-64 Rockwell resist wear. Since minimum burr height, well accuracy dimensions, essen- tial the user, great care must exercised the determination clearances between punches and dies. slight variation thickness hardness material being used can make material satisfactorily workable unworkable with given die clear- ance. Once the type has been selected, this condition makes essential that punches and dies made within close tolerances order produce stampings with minimum burr and thus reduce rejections. accuracy plus minus 0.0001 in. the tolerance used most types dies made the Allegheny Lud- lum shop. Clearances each side punches are recommended for various types die steel removal per grind and the longest possible die life, while pro- ducing the highest quality magnetic core laminations. The great loss involved the break- ing solid die has been responsible for the adoption the practice using dies built sections. The complex geometry some the parts fabricated also makes neces- sary that some dies built sec- tions order facilitate grinding. Sectional Dies Under the system using section- dies, any breakage localized and may repaired the insertion new section without the necessity making entirely new die. Spare parts for extremely complex sections can made advance and stocked equipment and with toolmakers trained work extremely close tolerances. The close tolerances necessary pro- duce parts sufficiently exact cannot achieved ordinary grinding equip- ment. The practice the toolroom the Allegheny Ludlum die shop buy the best equipment available and most cases recondition the ma- chine before putting into operation. This rebuilding involves painstaking hand scraping ways and special fitting all bearings degree accuracy necessary turn out work with tolerances plus minus 0.0001 in. addition the usual gages and instruments, optical com- parators are required giving mag- complex die contours. Most the grinding machines are provided with THE IRON AGE, May | | 4 | magnetic chucks, and magnetic jigs are used for positioning parts which must ground special angles. Since the best die punching steel with ideal stamping qualities can ruined defective press, special care must given press room equipment. Allegheny Ludlum fol- lows practice relation its press- similar that its grinding equipment. When new press bought, usually torn down and rebuilt. Some parts are chromium plated minimize wear and all bear- ings are specially fitted insure accu- racy and long life. systematic program inspection and maintenance followed all press equipment. This keeps crew maintenance men constantly busy checking and repairing the presses. Progressive Dies Progressive dies are used for most jobs. These dies consist number stations where such punching op- erations piercing, slotting and blanking are performed sequence. the case typical rotor and stator die, the sequence follows: Pierce rotor, blank rotor, trim air gap, slot stator and blank stator. This type die produces laminations suit- able for automatic stacking and per- fect alinement from the press, thus saving labor and money comparison the compound method. One interesting the production “no scrap” transformer laminations. ‘These consist “E” and “I” shapes. They are designed obtain both maximum material economy and electrical performance. The only loss the material due 54—THE IRON AGE, May 1945 the holes, and the best electrical performance obtained having most the section the direction rolling. Following close tolerance slitting, shown Fig. the holes are punched from the strip the first station. The pieces are then blanked out, form- ing the windows the “E” pieces. The “E” pieces are then blanked. Two “E” and two “I” pieces are produced with ‘each stroke the press, shown Fig. pertinent note that the economy material affected making the length the pieces twice the length the “E” windows. After punching, the laminations are inspected, and stacked and are then wired together preparatory anneal- ing. Annealing most types steel performed electric furnaces un- der controlled atmospheres. Proper temperature recording equipment essential for correct annealing. The annealing highly permeable nickel alloys conducted under dry hydrogen high temperatures with suitable inert material between the Grade Steel Gage Transformer grades........ 0.0007 Dynamo special........... 0.0007 0.0005 0.0005 Punch Clearances Recommended for Various Electric Steel Grades 5—Apparatus developed Al- legheny for measuring core loss and exciting current testing stator laminations. laminations keep them from fusing. Equipment and control this anneal- ing process are complex and deli- cate that the company recommends that users this type steel for stamping not attempt annealing themselves, but return the lamina- tions Allegheny Ludlum for anneal- ing. The department has extensive facili- ties for testing stacks laminations order determine the magnetic performance the core material. making tests, the laminations are as- sembled into finished cores and are placed windings similar those used the final assembly, duplicate nearly possible the conditions actual use. Some the testing apparatus used these items are shown Fig. The result the policy accuracy and control throughout the entire process has permitted the organiza- tion achieve not only some outstand- ing individual records the life (Continued page 135) Clearance Recommended, In. Gage Gage Gage 0.00085 0.00085 0.00075 0.00075 0.0009 0.0015 = . NEW oxy-acetylene emergency outfit for use battle damage conditions weighs only lb. its fire resistant canvas back pack and compares with earlier equip- ment weighing almost 200 lb. that requires least two crewmen man handle it. The new unit consists two cu. ft. capacity oxygen cylinders and one cu. ft. acetylene cylinder, gas regulators, hand cutting torch, hose, asbestos gloves, lighter, goggles and tools. Oxygen cylinders are con- nected manifold and regulators are designed control automatically the supply gases the cutting torch. All the operator must be- fore using the unit open valves the cylinders. cases where battle damage has caused the jamming compartment doors where twisted steel wreck- age needs cutting away prior re- pair work, single operator with his portable cutting gear can cut his way into damaged spaces, making way for fire hoses and repair parties. Men trapped compartments have been quickly rescued immediate use the equipment, and fires have been reached and controlled that might have caused severe damage. Rapid replacement gas cylinders accomplished arranging all three cylinders units, with oxygen manifold already attached the cylinder valve outlets and the cylinder set clamped aluminum cradle. change cylinders accomplished detaching the gas regulators from the cylinders, removing the empty set from the pack, replacing with fully charged set and reattaching regula- tors. The gas capacity one set unit cylinders will cut approxi- mately 225 lineal inches in. steel plate. The probability that the new emer- gency cutting outfit will used ° ° ° UTTING away ragged edges battle damage with acetylene cutting torch pack. Two large tanks hold cu. ft. oxygen, the small one cu. ft. acetylene. Note readily de- tachable regulator. ° UTTING deck plate with port- able Com- plete unit proof canvas pack stores small alu- minum locker. relatively untrained operators under battle damage conditions necessitated the development special pre-set gas regulators assure adequate flow oxygen and acetylene the torch. The gas regulators are small and compact design reduce the overall dimension and the complete outfit. Specifications developed the Bureau Ships required suppliers produce pre-set pressure, 2-stage oxygen regulators and similar single stage acetylene regulators. Service tests assured safe and economical de- livery gases under the most critical battle damage conditions regardless operators’ nervousness in- experience. Effect Phosphorus the Hardness Quenched Cast Iron investigation which speci- mens five cast irons contain- ing 0.12 per cent, 0.35 per cent, 0.52 cent, 0.91 per cent and 1.18 per phosphorus were quenched water and oil after holding tem- peratures 1292 deg., 1472 deg. and 1652 deg. for periods hr. described Bischof Giesserei, 1944, vol. 31, April, pp. 55. After quenching from below the point, the hardness was less than that the as-cast state, owing the formation pearlite; in- creasing the holding time did not affect the hardness this case. temperatures 1472 deg. and 1652 deg. F., increasing the hold- ing time decreased the hardness after quenching. For temperatures 1652 deg. F., the highest hardness was ob- tained with the iron containing 0.52 per cent phosphorus. The reduction hardness after quenthing was due the phosphorus promoting the precipi- tation carbon from solid solution. THE IRON AGE, May 1945—55 Navy Cutting Torch Pack Cutting Torch Pack Weighs Lb. ions ting racy ntire niza- Silver Brazing Aircraft Production Because requires less skill and training, silver brazing re- placing gas and arc welding the fabrication many the smaller component assemblies. The various methods silver brazing currently use are reviewed the author and the factors making for sound assemblies discussed. mands were made upon produc- tion departments manufactur- ing welded assemblies for aircraft. The shortage skilled welding opera- tors was acute. Therefore became imperative that something done increase production without crease personnel. Several ap- proaches this objective were im- 1944 increased de- reducing the weight. mediately studied. Among these was the use silver brazing substi- tute for older methods fabrication welding. Casual observation im- mediately pointed several assem- blies where the use silver solders not only increased production but actually improved both the appear- ance and strength the job while More intense ° WEED General Foreman, North American Inc. Inglewood, Cal. study the possibilities the use silver brazing aircraft assem- blies resulted the redesign some assemblies and the procurement equipment with automati- semi-automatically controlled heating. the use these con- trolled heating devices has become more general, the field for the use silver brazing alloy aircraft has become almost unlimited except for certain highly stressed members. was found that the high degree ductility and malleability silver brazing alloys gives two important advantages: First, joints made with them provide great resistance vi- bration and severe shocks. Second, assemblies can fabricated easily Typical silver brazed aircraft assemblies IRON AGE, May 1945 ° i in al ac ed ne al ‘ into wide variety sizes and shapes, thus making possible obtain joints the form most con- venient and economical for the dif- ferent conditions under which they are used. Silver alloys can applied any type joint. Although scarf, lap, and sleeve joints sheet metal, pip- ing and tubing have the advantage providing greater bonding area than butt seam joints, experience has shown that the strongest joints are produced with minimum amount clearance. The free flowing char- acteristics silver alloys makes possible and advantageous pro- vide closely fitted joints that require small amount silver brazing alloy. Properly fitted joints are eco- nomical the use silver alloys; and the neatness these joints, RIGHT NTERIOR sandblast cabinet used preparing steel parts for brazing. Shown the tailwheel trated elsewhere. BELOW sembly silver brazed. which many cases are practically invisible the naked eye, often decided advantage where plating, painting other processing re- quired. Silver has qualities. When melted extreme- fluid. also one the most ductile metals. Its electrical con- ductivity per cent higher than copper. When alloyed with other extraordinary common alloy for brazing ferrous metals contains per cent silver, cent copper, per cent cadmium and per cent zinc. melts 1160 deg. and flows freely 1175 deg. which metals, such copper, for example, silver unites form compositions’ having flowing temperatures lower than either the individual metals. The extreme fluidity melted sil- ver base brazing alloys gives them the ability penetrate quickly into narrow openings. spreads them evenly over the surfaces joined where they diffuse into Capillary action metal surfaces and form practically indestructible. Low working temperatures and rapid penetration thus make silver brazing exceptionally fast method join- ing metals. The ductility and strength given THE IRON AGE, May 1945—57 e | “3 i ~ i ‘ ABOVE NDUCTION unit setup brazing, showing type jigging em- ployed. RIGHT YPE jigging used for silver brazing with oxy- acetylene torch silver are also closely related their flowing qualities. Silver brazing al- loys themselves are strong, having strengths from 40,000 60,000 lb. per sq. in., but when thin films penetrate into joint and bond with metals, they have the unique ability give strength far beyond their basic strength. the utmost importance that silver brazed joints properly de- signed. The correct design mainly question the type joint use and the clearances required. the three types joints general use: butt, scarf, and lap shear, the lap 58—THE IRON AGE; May 1945 q shear type joint the de- sign generally recommended al- though the others can used satisfactorily under some con- ditions. Lap type joints are generally used because any desired fac- porated varying the lap shear area. This type joint offers better resistance corrosion due the small area braz- ing exposed. Joints can joining flat parts, little sure will insure complete bond- ing. shear joints, which in- clude tubular members, pressure cannot exerted and correct clearance must maintained insure proper capillary action. setting procedure for produc- tion silver brazing, there are five simple but important factors observed: 1—Clearance between parts. 2—Cleaning metal surfaces. joined. 4—Locating device jig. 5—Heating method. Clearances for silver brazing are important. Metal joined should fit closely enough permit the effec- tive working capillary action. From held place readily, and experience the laboratory and field, has been found that clearances from 0.001 0.006 in. flat tub- ular work give the strongest and soundest joints. Clearances which are too close cause bare spots where brazing alloys are unable flow. Enough clearance should allowed make certain that there will film brazing alloy throughout the joint. When brazing alloys are pre- placed the form thin inserts, little pressure the joint while heat- ing, forces out excess alloy and leaves film that takes care irregularities joint has been found that absolute necessity have the sur- faces the joint clean and protected with flux. Grease, oxides, scale, and dirt any kind must removed; extra care taken this regard will eliminate many the causes de- fective joints. and chem- ical can used either to- gether individually required. “Metal Cleaning Before Silver March 22, 1945, page 56. The temperatures required for the use silver brazing alloys will cause the oxidation the surfaces both the silver and metals being joined and provision should made for pre- venting this oxidation far pos- » and for the removal any oxides which may form. effective job, brazing flux should entirely fluid and active tem- perature below the flowpoints the brazing alloys with which used. fluoride type paste flux begin- ning fuse 800 deg. should start dissolving oxides immediately. colorless fluid actively dissolving all refractory oxides, chrome oxides. The use flux temperature indicator strong- recommended, particularly oxy- gen acetylene torch applications where difficult for the operator determine when the metal parts have reached the temperature ap- proximately 1200 deg. Where study and consideration are given the jigging the parts silver brazed, uniformity results can expected. Particularly this true where production prime con- sideration. often the case where furnaces are used where number parts are brazed simultane- ously, the jigging all parts RIGHT ing steel assemblies. SEMBLIES and preplaced alloys entering electric furnace prior brazing. Hydrogen used for the furnace atmosphere. heated silver bath used dip braz- trained for this work and then turned over the who handle the heating the metal. Preassembly spot welding, staking, and rivet- ing are the three most commonly used methods furnace and dip brazing. torch and induction brazing, use made most frequently suitable jig with properly designed holddown clamps. Choice Equipment Choice the heating method will predicated several factors: the type work, volume products and the availability equipment hand. Since most shops have oxy-acetylene torch equipment, natural that venturing into the new field silver brazing, such equipment will used. confidence results established, ‘and the work warrants speed production, other methods bringing metal temperatures approxi- mately 1200 deg. are investigated. Furnaces heated oil, gas, electricity using either the batch prin- ciple conveyors are conducive ¥ ‘ -_ > rapid production small parts large volume. Parts brazed are fluxed and silver alloy preplaced be- fore going into the furnace. Tem- perature the furnace should excess the flow point the alloy for fast heating. Incandescent carbon resistance heat- ing electro-brazing lends itself the silver brazing parts. The part brazed placed between the electrodes and held position pressure the tongs. Insulated electrical parts can joined this manner without fear damage insulation. Whether hand feed the silver alloy preplace thin in- sert form depends upon the job. Resistance brazing responds the ingenuity and equipment available production management. Those who have used this method heating parts silver brazed have found answer heavy production types work where practical preplace the alloy. Dip brazing the employment the metal bath the chemical bath. The metal bath requires that parts held brazing position and dipped into molten bath brazing alloy. Brazing this kind used mostly join comparatively small work. Crucibles for holding the molten alloy may heated gas, oil electric- ity. The chemical bath also offers the advantage fast heating and, does the metal bath,