The Iron Age 1940-04-11: Vol 45 Iss 15

VAN DEVENTER President and Editor BAUR Vice-President and General Manager Managing Lditor News Editor Editor Emeritus Wwachinery Editor Art Editor Metallurgical Editor Associate Editors Washington Editors Resident District Editors CAMPBELL ROBERT BINGHAM Pittsburgh Chicago Clevelana Detroit Correspondents Buffalo Cincinnati G. FRAZAR P. FipRMuc Boston Hamburg, Germany MEYER CHARLES Post Milwaukee San Francisco Toronto, Ontario Birmingham 2 April 1940 ALLISON Roy EpMONDS Newark, N. J St. Louis Day for Industry Comments Electrolytic Polishing Straight-Line Galvanizing ADVERTISING STAFF B. L. Herman, Cnilton Bldg., Phila Hl. K. Hottenstein, 1012 Otis Bldg., Chicago A. H. DIX, Manager Reader Service Peirce Lewis, 7310 Woodward Ave., Detroit (. H. Ober 239 W. 39th St., New York ° . . Robinson Park Pitts. Report American Gas Association W. J. Fitzgerald § Db. C. Warren, P. O. Box 81, Hartford, Conn — a Harner. 1595 Pacitie Avenue, Long What's New in Machine Tools 54 Cal Member, Audit Bureau of Circulations On the Assembly Line 60 Member, Associated Business Papers Indexed in the Industrial Arts Index. . Published every Thursday. Washington News tion Price: United States and Pos- sessions, Mexico, Cuba, $6.00; Can- ada, $8.50; Foreign, $12.00 year. THE NEWS BRIEF Single copy, 25 cents. Annual Num- Weekly Ingot Operating Rates Rate Activity Capital Goods Owned and Published by CHILTON COMPANY (Incorporated) Editorial and Publication Office Executive Offices Chestnut and 56th Sts., 239 West 39th St., Philadelphia, Pa., U.S.A. New York, N. Y., U.S.A Plant Expansion and Equipment Buying 118 OFFICERS AND DIRECTORS Free Industrial Literature 122 MUSSELMAN, President JOS. HILDRETH, Vice-President Products Advertised 146 GEORGE GRIFFITHS, EVERIT TERHUNE, Vice-President Just Between Two 147 VAN DEVENTER, Vice-President BAUR, Vice-President Index Advertisers 174 WILLIAM A. BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS L. KANE, G. C. BUZBY, P. FAHRENDORF HARRY V. DUFFY CHARLES J. HEALE Copyright, 1940, by Chilton Company (Inc.) te cd ARP | 2 ‘ Tons and Tons Steel Euery Certified RYERSON PLANTS carrying more than 10,000 sizes, kinds and shapes steel products are ready meet both your regular and emergency steel requirements—and you get Ryerson Certified quality extra cost. Under the Ryerson Certified Steel Plan, every pound steel carried stock represents the highest quality available each particular classification. Analyses, accuracy, finish, all steels are closely controlled. special quality control plan the alloys gives the heat treater exact data every bar. Testing, experi- menting and retreating are eliminated and dependable, uniform heat treatment response Ryerson offers complete steel-service. Experienced crews working with modern facilities quickly cut and prepare the steel meet your most exacting requirements. There’s waiting, delay when you order from Ryerson. Stocks are complete. Delivery prompt. Save time, trouble and money concentrating all your steel requirements with this one dependable source. Write for the Ryerson Stock List—the Key Profitable Steel Buying. Joseph Ryerson Son, Ine. Chicago, Milwaukee, St. Louis, Cincinnati, Detroit, Cleveland, Buffalo, Boston, Philadelphia, Flame cutting the most intricate parts Jersey City. from heavy plates valuable feature Ryerson ait he Yffyyy Ys UW ... THE IRON AGE ... APRIL 1940 ESTABLISHED 1855 Vol. 145, No. “M” Day for Industry VERY industrialist this country knows about Day. The plans have been carefully laid for elaborate detail. When and that day announced, American plants will immediately begin turn out weapons defense with which repel the enemies freedom. one questions the wisdom preparedness. Especially preparedness for the preserva- tion freedom. It's first class investment. Day looking toward prompt defense American institutions from possible attack from abroad good thing. It's nice know that are doing something about and are not likely caught again with our pants down. But what about Day prep- aration for defense American freedom against its enemies home? General Johnson has pointed out, the likelihoad foreign power combination them attacking the United States after this war over quite unlikely. Modern war destructive values, even conducted along economic rather than military lines, that winners and losers alike emerge from weakened and not strengthened. will take years, least, for Japan recover from her friendly little excursion into the heart China, she indeed manages find her way home again. Germany will not frame mind undertake overseas adventure after her citizens realize what the present one has cost them. for Russia, her demonstration against little Finland should make write her off our books first-class military power. No, the immediate danger American freedom not abroad but home. lies the inordinate ambitions unelected bureaucrats, the distorted thinking assorted crackpots and the insidious planning and plotting the communistic-minded high places. For though these vermin have disavowed the name since Hitler made Communism unfashionable Amer- ica, they are still gnawing away industriously ever the framework and foundation our freedom. You cannot change the smell skunk calling him polecat! need Day for defense freedom against its home. Not Day for the production guns and ammunition but Day for the dissemination information our citizens. Information what constitutes freedom and what necessary maintain it. That is, doubt, why the able president the N.A.M. last week called upon industry mobilize defense the American System Enterprise. mobilize marshalling the facts about industry's relation the public welfare and send these facts marching into every corner America. Mr. Prentis has pointed the truth that religious freedom and freedom speech are inseparably tied freedom enterprise. When one falls, all fall. The point attack today freedom enterprise. Let's rally the call defend it! | He \ a a ¥ ~ 4 WHEN THE HEN “tough” draws are easily made and reject losses drop, the result greater profit. This can happen only when the right quality sheets fitted shop equip- ment, fabrication methods and product. Inland experienced metallurgists are able and willing study your problems and recommend the steel best suited your steel that will take your “tough” draw, reduce rejects the minimum, make finer products and add your profit. your request, Inland metallurgist will call your plant discuss your problems SHEETS STRIP TIN PLATE BARS PLATES FLOOR PLATES STRUCTURALS PILING RAILS TRACK ACCESSORIES REINFORCING BARS ; a j > 4 Dearborn Street, Chicago Sales Offices: Milwaukee, Detroit, St. Paul, Kansas City, polishing steel, copper, brass, zinc, nickel, aluminum, monel metal, etc.—electrochemically rather than mechanically tech- nique which rapidly expanding and improving. What exactly the action such electrochemical What the condition the metal surface after the baths operate? And what may expected commer- cially such electrochemical polishing? All these inquiries are answered the authors herein. URING the past few years con siderable attention given electrolytic polishing metals and the past few months publicity has been given polishing stainless steel electrolytic methods. Polishing methods have been under in- vestigation Battelle Memorial Insti- tute for several years, and repeated requests have been made discuss havior Copper Aqueous Solutions Or- Acid,” Transactions Electrochemi cal 69, 629-655 (1936); (b) Jacquet, Method Preparing Perfectly Polished Metallic Comptes Rendus, 201, 1473-5 (1935); (c) Jacquet, anism Electropolishing Copper,” ibid, 202, 402-4 (1936). Deterioration Brass Surfaces Mechanical Journal Chim. Phys., 33, 226-31 (1936). Copper, Lead, Tin and Their Alloys and Its Application Soc. Chim., 705-13 (1936); (b) French Patent Fink and Kenny. “The electrolytic processes, their mechanism, scope, and usefulness. This paper does briefly. All electrolytic polishing processes have certain characteristics com- mon. They function anodically and produce “polish” “brightness” virtue selective removal metal from the surface. Jacquet’ described anodic polishing Transactions Electrochemical Society, €0, 235- 270 (1931); (h) Fink and Kenny, Treating Metal and Alloy Articles Improve the Resistivity Thereof Corrosion and the Product Patent June 1934. Lindh, “Method Brightening Nickei 1939. Schaefer, “Anodic Polishing Industry (N. Y.), 38, [1], 22-26 (1940) 7S. Blaut and Lang, “Electrochem ical Treatment Patent 2,115, 005, April 26, 1938. 8G. Kiefer, “Electrolytic Polishing Stain less THE TRON AGE, 144, [25], 32, 66-7 (1939). Lippert, Polished Stainless THE IRON AGE, 145, [2], 22-26 (1940). copper for metallographic purposes phoric acid. concluded that while bright surface was obtained the proc- ess did not constitute “polishing,” but differentiated from nitric acid pickling effected uniform attack and did not yield matte surface. Jacquet also discussed polishing metallo- graphic specimens and other Earlier than these Jacquet papers, however, Fink and Kenny* determined that metals are equipotentialized when subjected anodic treatment certain solutions. shown later this paper, equipotentializing and pas- sivating can effected when metals are electrolytically polished. anodically brightened nickel nickel coatings strong solution acid. discussed anodic polishing metallographic specimens various metals and alloys. Blaut and outlined process polishing stainless steel bath composed sulphuric and hydrofluoric acids. stainless steel anodically, states that the treatment produces passivating effect and concludes that the only ad- vantages gained connection with corrosion result from the formation smooth surfaces. sketched recently the com- THE IRON AGE, April 1940—33 Me ; 4 ° ° ° 4 4 IG. 0.0005-in. nickel plate mechanically polished and electropolished (below) stainless steel. The un- distorted austenitic grains the electropolished surface have been revealed selective deposition nickel whereas the continuity structure the nickel deposit has been destroyed the layer resulting from mechanical polishing. Unetched, and 100 > 4 Ch) 34—THE IRON AGE, April 1940 mercial status, known him, electrolytic processes applied stainless steels, particularly stressing the operations under the process de- veloped Rustless Iron Steel Corp using bath composed citric and acids. Chemistry Electropolishing its studies metal surfaces. Battelle Memorial Institute has inves tigated polishing and passivating meth ods, including anodic treatments, Early the studies became apparent that development electropolishing proc esses comprised more than the mere development bath. Polishing proc- esses must tailor-made; chemical. electrical, physical, mechanical and engineering features must estab lished not only for the different metals and alloys but also for different given metal. Knowledge the mechanism anodic dissolution metals neces sary understand the principles volved anodic polishing. When metals dissolve anodically, surface film may form and thus disturb the process. the film non conducting and only partly covers the anode surface, the free portion the surface will subjected dissolu tion greatly increased current den sities the same total current main tained. The film and its nature de- pends many factors, including the current density, electrolyte, tempera ture, solubility dissolution products characteristics. obvious that the anode process will governed the electrochemical properties the ions the electrolyte used. Work done Battelle many different kinds metals and baths has shown that anodic polarization tude invariably accompanies polishing polishing from selective removal elevations the metallic surface and can occur only the rate dissolution elevations greater than the depressions. This effected when depressions are rela tively anodically passive and the ele- vations relatively anodically active. unnecessary define the exact nature the anodic film because its function laver gas, film insoluble anodic reaction product, static liquid film highly concentrated anodic products. Anodic activity, course, evidenced loss metal from the anode during electrolysis. Metals are polished baths that permit anodic dissolution that metal through highly polarizing | bg may reasonably expected that there will attack elevations the surface where the passivating film thinnest with less attack the depres sions where the film more protective Under these conditions the anode effi- ciency the elevations may high, whereas the polarization high and the anode efficiency low the depres- sions. Any bath and operating con ditions combining high anode polariza- tion and greater anode efficiency elevations than depressions should effect anodic polishing hemogene- ous metal. the case metal alloy whose structure not homo geneous, required further that the bath and operating conditions provide film that will prevent selective anodic phases. Fundamentally, solution that will bring about these conditions neces sary. This alone, however, not suf ficient insure commercial success The bath must have proper throwing power handle intricate designs and shapes without the use too compli cated and unwieldy cathodes. com- pete with mechanical processes, elec trochemical ones must simple. given bath and set operating condi tions may effective for polishing simple object such wire, same set-up may entirely ineffective for handling casting stamped object. The electrochemical behavior the metal ions anodically formed the electrolyte governs large mea sure the nature the vating film; there universal solution, and the electrolyte adapted the anode being polished. Electrolytical vs. Mechanical Polishing Comprehension the differences mechanical methods polishing necessary appreciate fully the nature the prod chanical polishing the high spots elevations are removed, caused flow, until substantially flat surface results. The cold working operation changes the nature the surface which characterized “amor- phous” “pseudo layer. electropolishing, the surfaces the grains the metal being treated are rendered substantially level and highly lustrous without distortion and passivates the surface thereby in- creasing resistance corrosion. The degree passivation depends the metal, the bath and the electropolishing studies difference hetween the two types polished surfaces. For example, plated metallographically polished specimen stainless steel shows structure ordinary magnifications. “amorphous” layer. When nickel plated electrolytically polished surface stainless steel, deposits such way continue the crystal- line structure the stainless steel. This shown accompanying photo micrographs. Electron diffraction studies made shown the photographs mechani- cal and electropolished samples which were simultaneously exposed the atmosphere analytical laboratory hood. The existence invisible passivating film electropolished surface clearly demonstrated the photomicrographs identically etched mechanical and electropolished sam- ples. General Considerations anodic polishing processes the electrical requirements are quite simi- ELECTROPOLISHED NO. MILL FINISH 2—Mechanical and electropolished samples stainless steel that were simultaneously exposed for days the atmosphere laboratory hood. The passivating effect the electropolishing treatment strikingly evident. The extreme top the electropolished sample was un- treated and the top portion both was lacquered preserve the origina finish. Battelle steel, plain carbon steel and aluminum indicate, however, that the electron diffraction patterns with those the same surfaces pol ished mechanically. The probable planation that thin film, probably oxide, covers electrolytically pol ished surfaces and gives rise the diffusion-ring type pattern. These studies substantiate the conclusion that electropolished surfaces are passivated Further evidence passivation lar those chromium plating. most chromium plating plants can operate polishing unit with their equipment merely reversing the rection the direct current and pro viding proper solutions and containers. Lead lined tanks are suitable for most polishing baths, but use the tank itself cathode not good practice. Current density important but many instances not critical. Usually there minimum current density that must exceeded, but the upper THE IRON AGE, April «<2 = ; 7~ a (above) and electropolished (below) stain- less steel after being subjected identical etching treatment glycer-regia solution. The pinholes appearing the electropolished sample demonstrate the existence invisible film and are the re- sult attack this active etchant weak spots the film. The film can destroyed and the characteristic austenitic structure the steel can revealed continued etching. diameters. 36—THE IRON AGE, April 1940 limit depends more contact limita- tions and heating solutions than electrochemical phenomena. The mini- mum current density required sig- nificant and general those processes characterized low minimum cur- rent densities have marked advantages over those requiring high ones because much easier get the current into the article being polished, dis- tribution current better, and con- tact problems are less troublesome. has been observed, for example, polishing wire baskets racks that distribution current interior wires relatively small attained only with great difficulty processes requiring high current densi- ty, but the problem when conditions permit the low moderate currents. The mini- mum current density depends the work and electrolyte, and some cases may low amp. per sq. ft. Usually, speed demands higher current density, but for most metals and alloys possible oper- ate successfully amp. per sq. in. less. Voltage drop depends the baths used, the current density, the tempera- ture and anode and cathode spacing. Higher current densities usually de- mand higher voltages. general, voltages are the same order chromium plating, but for greater flexibility 12-volt generators are ad- pointed out, highly polarizing baths are necessary, and for that reason they usually contain only limited amounts water. Higher water contents reduce the electrical re- sistivity the bath, but increase the danger etching. The ance must, therefore, made. great deal attention has been paid this feature baths and can now reported that baths have been devel- oped which the water content, while critical, has wide enough working range commercially practicable. considerations pol- ishing processes must based baths that have been used “aged” dissolved the bath longer the simple one started with. important consideration any commercial use polishing methods corrosive poisonous fumes. This has been kept mind, and none the recommended processes have these objectionable fea- tures. while important, not necessarily critical. Usual tem- peratures are about 115 deg. 160 deg. For greatest flexibility provi- sion should made for both cooling and heating. | | | | | of successful, baths and operat- ing conditions must Having developed satisfactory bath for given metal, still necessary determine the proper operating con- ditions including temperature, current density, rate movement the anode relative the solution, and the anode- cathode spacing and arrangements. The aim Battelle has been correlate the necessary factors and work out baths and operating conditions not only for different metals and alloys but also for various forms and shapes. Baths and conditions have been found for polishing plain carbon steel, stain- including both chromium and chromium-nickel types, copper, brass, zinc, nickel, aluminum, monel metal, and other metals. Metals containing substantial amounts graphitic carbon have not been suc- cessfully bright polished. While straight-chromium stainless quire more restricted conditions for polishing than the nicked chromium varieties, processes have been worked out for the former. Electropolishing has been successfully applied vari- ous shapes, strip, sheets, forgings, stampings, castings, tubing, and intricately shaped objects. Another operating factor the life contact materials. commercially successful process must have long contact life, and baths and operating conditions that are otherwise success- ful may fall down for this reason. Racks, likewise, fall into the category. same This trouble has been suc- cessfully overcome. example, bath has been developed which suc- cessfully polishes stainless steel but which copper polarized that at- tack substantially nil; this bath copper racks and bronze contacts give long life. The cost electropolishing other than labor largely that chemicals and power. The latter depends the amount metal that must moved. The former governed the initial cost the chemicals, drag-out, and bath life, which may expressed terms the metal anodically removed. The chemical and the power costs per unit surface area treated depend also the nature the initial surface and the finished surface desired. Knowledge the chemistry involved necessary in- sure long bath life and provide trolyte. Scope and Limitations The authors have found that many people are misinformed about the scope and realm usefulness electropol- ishing methods. Many have the idea that electro methods Electropolishing gains the same end mechanical methods and addition yields passivated surfaces, can used irregular shapes and capable producing novel finishes rough smooth surfaces. Best results are ob- tained when the initial starting sur- face good. There justification for expecting start with rough sand casting and end with smooth mirror-like finish, any more than expect start buffing the same casting mechanically without the prior use grinding wheels and abrasives. However, the electropolish- ing sand casting will produce briliant rough surface that cannot obtained mechanically. Also, quite feasible for the electrolytic method polish intricate shapes that are dif- ficult, not impossible, polish me- many cases metal finishing, electropolishing suffice; others, should used conjunction with mechanical meth- ods. some instances may nec- essary follow electropolishing with mechanical buffing. common query whether die marks are removed accentuated. Those which are merely manifesta- tions cold working forming are easily and rapidly ings which are actual scratches may removed they are not too deep. Electropolishing tends round off sharp edges and minimize the effect scratches even though they may not eliminated completely. Scratches that are not too deep can removed completely, but their elimination neces- sitates removing layer metal con- siderably greater than the depth the scratches. cannot stressed too strongly that electropolishing essen- tially finishing rather than rough- ing operation. Also, the question asked, long does take pol- ish?” This cannot answered absolute terms because the amount metal that must removed depends the surface start with and the ultimate finish desired. specific example, with stainless steel strip may possible get the required brightness removal 0.0001 in. surface, but stainless formed object may have surface blemishes that will require removal 0.001 in. Unique and beautiful fin- ishes that range from satin mirror brightness may obtained proper adjustment bath, operating condi- tions, and the amount metal re- even more. moved. The amount surface that must removed also depends the size, shape and contour the work. small rounded object like wire may satisfactorily brightened and even polished removal enough metal give surface which would en- tirely unsatisfactory larger shape flat surface. Sheets are probably the hardest objects polish because reflected light their flatness tends would undetectable formed marks, crystal markings, are most obliterate shapes com- prising large plane areas. per- fectly general figure, but one that can used rough approximation for ferrous alloys, copper, brass, and nickel, with current density 250 amp. per sq. ft., 0.001 in. surface will removed about min. Stop-Off Lacquers Used Electropolishing particularly adaptable intricate shapes and sur- faces with crevices and cavities that are hard and expensive mechanically. selection bath proper electrical characteristics and with the right cathode design, quite complex shapes can handled satis- factorily. The process can used finish per and finish for base metal subsequently electroplated. Specific applications the latter are polishing brass and steel preparatory nickel plating polishing nickel preparatory chromium plating. Lacquers are available stop off areas sections that are not anodically attacked. Use these also permits etched designs produced that are polished the areas attacked. The raised areas can either polished natural desired. The chief axiom considering ap- plication electropolishing use judgment based knowledge its limitations well its possibilities. mentary and auxiliary mechanical methods. some instances will supplement and other supplant pol- ishing and buffing. the end the choice all boils down matter dollars and cents. Electropolishing resolves itself into adopting principles applied electrochemistry employing tailor-made baths and operating con- ditions for different metals and ap- plications. Success depends intel- ligent use the right places. But, there denying that many plants realize substantial savings using electropolishing methods fin- ishing. THE IRON AGE, April 1940—37 | he, : = gh | ve | Tr Wheeling Steel Corp., Steubenville, has just installed group new attention has been turned mak straight-line sheet galvanizing units, with speed range 135 ft. new and easier methods This first lete installati binati volt controlling the speed the sheets min. This first complete installation combination voltage control they pase through the field control individual electric motors the various components, gives accurate synchronization that essential this type equipment. The various units which are neces- sary the manufacture galvanized sheets, including the unit, the galvanizing machine rig, the spangle conveyor, dip galvanizing sheets the bath itself. Over the last few veyor, washer and squeezer, drying always has been process re- years considerable amount regu- conveyor, and finally, the roller leveler, quiring close control, both lating and metering has been done have but recently been organized into the speed the sheets going through the control the temperature the smoothly running team. With these the hot zinc and the temperature bath. Even more recently, how- various elements coordinated into Sulphur Spangle conveyor Cooling conveyor Corp., Steubenville works. Seven other Galvanizing machine 38—THE IRON AGE, April 1940 | | | | 4 | Gas machine, the flow sheets continuous from the galvanizing pot through leveler and the storage racks. McARTHUR Chief Engineer, Wean Engineering Co., Inc., Warren, Ohio and GEUDER Engineer, Reliance Electric Co., Cleveland Because the flow sheets con- tinuous process, becomes absolutely essential that the various pinch rolls, chronized with each other give ex- actly the same lineal speed strip for each unit. The principal pieces equipment which require chronization are: (1) the entry flux machine; (4) the spangle conveyor rolls, (2) the bottom rolls, and (3) the exit coating rolls the galvanizing (in some units this may special conveyor through furnace for mak- Pass line Floor line double bottom roll galvanizing line the Wheeling Steel galvanizing lines include four 50-in., one 50-58-in., and two 58-in. roll units. ing special product), and (5) the cooling conveyor, washer and squeezer rolls. The final unit ordinary line, the roller leveler, need not accu- ately synchronized, provided there sufficient space between the leveler and the squeezer rolls allow the sheets free themselves from the latter be- fore entering the leveler. fact, advantage run the leveler faster than the line, due the ease piling. absolutely essential that the first four units mentioned above accu- rately synchronized with each other. the first three are not accurately synchronized, the sheet will either buckle between the various sets rolls and come out with very bad shape, will pull tight between the rolls and receive bad scratches from the guides. the exit coating rolls and the spangle conveyor are not properly syn- chronized, the material likely scratched the conveying means and controlled spangles are being sought they certainly will not the type desired. Roll Speed Changes not always important syn- chronize the spangle conveyor and cooling conveyor. times, however, the spangles are not properly set be- fore leaving the spangle conveyor and such cases does become important synchronize the speed the cooling conveyor. all cases the material quite hot passes onto the cooling conveyor and is, therefore, very sus- ceptible scratching the speed the two conveyors not identical. Greatly complicating the problem accomplishing this synchronization the fact that the surface speed the various rolls varies rather widely THE IRON AGE, April | | im) i] ] 4 By the same r.p.m. This due part the redressing the various rolls, which must done rather frequently —sometimes often once every hr. for the exit rolls—and part the fact that the diameter the same rolls varies some extent during op- erations metal and oxides are built their surfaces. From this can seen that fre- quent changes relative r.p.m. the different rolls are necessary keep the lineal speed the sheet passing through them the same all times. Older galvinizing drives change gears attempting accom- plish this synchronization. This meth- subject the obvious disadvan- tages of, (1) having only certain few speeds available, and (2) the culty changing the gears while the machine running. contrast, the method driving each unit with separate electric mo- tor, which reduces mechanical parts extremely satisfactory for accomplish- ing the desired results. One other very important advantage obtained this type drive; namely, each set rolls the machine can stopped, started and reversed independently the others. the case cobbles this very great advantage, both pre- venting the entry new sheet into the machine where one already cobbled, and aiding the removing the actual cobble itself. For the reasons that have been out- lined, the multiple motor proved very successful. However, the first installation multiple motor drive used ordinary adjustable-speed d.c. motors and provided speed range most galvanizing lines require much large speed range, change gears some similar device had installed increase the speed range at- tained the motor. This increased the cost the mechanical equipment and added another point where chatter and undue wear could occur. The final step the simplification the drive has been the use vari- able-voltage control where very wide speed ranges much 13:1 can obtained without any change what- soever the mechanical setup and without the necessity interrupting operations. The recent installations the Wheeling Steel Corp., (Steubenville works) are, far known, the first complete installations com- bination voltage control 40—THE IRON AGE, April 1940 control electrical motors galvan- izing lines. They represent substan- tial simplification the mechanical equipment required. the same time, this type electrical turned out considerably cheaper than more conventional combinations wider, adjustable-speed motors and mechanical speed changers. These new galvanizing lines were purchased cover speed range from 120 ft. per actual practice they have been operated suc- cessfully over range from 135 ft. per min. Because the atmosphere around the galvanizing pots and span- gle conveyor, well around the first part the cooling conveyor, usually deemed advisable fully inclosed, fan cooled some installations the exhaust fan sys- tem for taking away the corrosive fumes has been entirely adequate keep the atmosphere relatively clean. This, however, the exception rather than the rule, and insure complete safety, fan cooled motors are generally used—and were used the Steuben- ville installations. has been said, the galvanizing when making change the speed the line, therefore, necessary bring the several units comprising past, rather elaborate inter-connecting controls have been re- quired enable the operator adjust all units simultaneously while the same time keeping them was, consequently, with view simplifying these operating conditions, that work was undertaken apply system variable voltage the individual elements composing the modern galvanizing The original line However, the flexibility voltage con- trol, worked out for the operating cycle desired, has made possible HIS new galvanizing depart- ment the Steubenville works the Wheeling Steel Corp. one the most modern the industry. Provision has been made for future expansion with additional divisions four units time being added required. Corrugating equip- ment also included the new department. and this has been successfully used The speed the entire galvanizing line the control the operator, who has merely operate “slow” push-button station speed slow down the entire line perfect synchronism. Vernier field rheostats supplied for several the units. They have served not only secure the initial adjustments, but make easy obtain such additional modifications adjustment may desired from time time realize the best oper- ating conditions. Fully inclosed, fan motors have been used all the units this variable voltage system. The se- lection combination control for the motors takes into account not only cor the range speeds covered, but also the high ambient temperature with which the motors must pared cope when operated very low speeds and reduced voltage. The main motor-generator set which supplies variable voltage energy the galvanizing line located some dis- tance away and its control, which in- cludes motor-operated rheostat, placed near for convenience. the galvanizing line itself there small operator’s panel which are provided the ordinary start and stop features and the speed control the entire line. addition, means reversing the entry rolls the galvanizing pot provided without disturbing the steady flow sheets through the remainder the line. The combination voltage control and field control was worked out fully after had been determined that fully inclosed, fan cooled, adjustable speed field control, even though they can successfully built, would have cost far too much justify their application this equipment. The have been installed are provided with field control, part which used the galvanizing pots compensate for wear all the rolls, and the rest combined with voltage control ob- tain the total desired range oper- ating speeds. The galvanizing pots these new lines have three motors. One handles the entry rolls, the second drives the bottom rolls, and the third operates the exit rolls. necessary that the speed relationship these motors re- main substantially constant that the sheets, they through the pot, will not pulled tight against the upper guides allowed slack against the lower guides. Ten hp. 850 1700 type Reliance motors are used and according test are liberal size for the application—a desirable condition because the high ambient temperature, the good regulation re- quired, and because they are fully in- closed, fan cooled, and must operate below normal speed. However, has been found possible take some ad- vantage the constant torque char- acteristics the load and have super- imposed the field control range the voltage control range such way that the speed goes below about r.p.m., the motors will operating about half normal armature current, substantially reducing heating. Equally liberal sized motors have been applied the spangle conveyors, and the combination drive for cool- ing conveyor, washer, squeezer, and drying conveyor. All the motors the line, with the exception the one which drives the roller leveler, are operated from voltage-controlled 30-kw. motor-gen- erator set. The roller leveler motor 25-hp. 400 1600 r.p.m. adjust- able-speed type and does not operate off the voltage control scheme because synchronization this point not particularly essential, other that that desirable have the roller leveler always running somewhat faster than the drier conveyor. Moreover, not necessary have wide speed range the roller conveyor the rest the line, and therefore has been divorced from the voltage control scheme. Operating results with the new pro- duction line have satisfying. The synchronization the several units the line, using the vari- able voltage control system, lieved the operator from otherwise and confusing multiplicity duties, and has made possible consistently uniform job sheet galvanizing. THE IRON AGE, April iy 4 + § | gas cutting 18-8 Ingaclad steel plate. Cuts are made from the mild steel side, and abnormally low oxygen pressures are used. OTTLE capping machines built the Crown Cork Seal Co., Baltimore, incorporate “crown- revolving wearing made 18-8 Ingaclad steel plate. Until re- cently trepanning set-up was em- ployed for cutting the plates finish rings measuring 23/32 in. outside diameter and 23/32 in. in- side. After some experimenting ma- chine gas cutting technique was devel- oped and now regular use. purchased, the clad plates are in. square and 7/16 in. thick, with the stainless steel portion 0.35 in. thick. For the gas cutting, Airco No. Radiagraph set shown Fig. employed. Before cutting, diameter starting holes are drilled the clad plate for both the inside and outside flame cuts. this type steel necessary cut from the carbon steel side for the reason that stainless steel does not oxidize readily, and important 42—THE IRON AGE, April 1940 utilize the iron oxide the carbon steel base accelerate oxidation the stainless steel, order neatly sever the entire plate thickness. Be- cause the need utilizing the iron oxide complete the cut, the machine speed and the oxygen and acetylene pressures are necessarily critical. Torch Set-Up this particular thickness plate (7/16 in.) was found that cuts such pictured Fig. are obtainable, using torch speed approximate- in. per min., and style 124 No. cutting tip raised approximately in. from the plate with soft neu- tral flame adjustment. Acetylene pres- sure lb. and oxygen pressure are used through 8400 series regulators. The plates are neatly severed and the kerf quite narrow. The slight amount slag left the stainless side easily removed, and sequent machining excessive hard- ness has been noticed resulting from the flame cutting. Furthermore, there virtually discoloration the highly polished stainless surface. IG. 2—Gas cut section resulted from the flame cutting, and highly polished used the “as condition, has been found that very thin solution “Handy” flux painted the stain- less side and allowed dry thorough- before cutting helps prevent dis- coloration. Small-Quantity Cutting similar work where time and quantity material cut does not permit adequate set-ups, cuts good quality can consistently obtained slight departure from technique described the foregoing. This is, setting the torch approxi- mately deg. from vertical posi- tion and pointing the direction op- posite torch travel. Use low oxygen pressure for the thickness cut with the inclined torch results greater amount iron oxide and more time for reacting the slowly oxidizing stainless steel. Definite obstacles present themselves ther be » % this type cutting, however, the foremost being condition noticeable the surface the plate being cut. The mild steel being severed but not the stainless the é stainless clad steel. excessive hardness there was virtually discoloration the stainless surface. able stainless steel wearing plates pro- tect the expensive housing CEM ers from the abrasion sliding bottles. The circular plates shown under the crowner are those rough cut the ma- chine gas cutting method. j Vike. Serviceman and Sales Engineer Respectively, Air Reduction Sales hottom side. This condition can caused by: (1) Use excessive pre- heat flames, which cause the two dif- ferent metals separate ahead the cutting jet; and (2) too high the same condition that the iron oxide blown through too high velocity, thus losing the oxide and the cut. low oxygen pressures are order. later lots this clad steel was found that the thickness the stain- aa less varied and caused trouble unless torch speed and pressures well tip sizes were changed correspond with the thickness differences. should also said that machine gas cutting must used for smooth torch cuts because hand cutting not suf- ficiently steady satisfy most com- mercial requirements. Although actual cost figures are not yet available, can said that the machine gas cutting these stainless- clad steel “revolving wearing plates” has resulted considerable savings. THE IRON AGE, April Wee | ° ° ° | 4 4. a LIPPERT Metallurgical Editor, The Iron Age week dealt with continuous casting which the mold wall with respect the metal flow, with the exception the mold, which kind in-between affair. And all these machines turn out rods, billets ingots. mentioned the beginning this article, the original Bessemer idea was pouring metal between two turning rolls, that is, the roll surface moving about the same speed the metal produced. This type direct casting turns out strip sheet. This original Bessemer within the past decade been pretty well dominated several designs ma- chines Hazelett, Hazelett Metals, Inc., New York. Just recently sim- ple high-speed Hazelett machine has been used experimentally great ex- tent, the speeds strip production be- ing the order 500 ft. per min. Many trial runs have been made with both silicon steel and various analyses 44—THE IRON AGE, April 1940 stainless alloys, and for the latter particularly there has developed great interest, based doubt the large market for stainless steel strip form. Just several weeks ago one the leading steel producers supervised trial run this new ring mill for 18-8 stainless steel, the strip produced being in. wide, 0.017 in. thick, and continuously cast the rate 450 ft. per min. The edges were quite clean and required only about trim. After passing along for further processing this strip was reported follows: “After some amazing and rather puzzling complications (mostly annealing), the final rolled product obtained was comparable every way with the product turned out con- ventional methods.” For number years Hazelett di- rected his attention casting-rolling mill, wherein the metal cast and given sizable reduction the same set rolls. number full-size commercial units this type have one time another been experimented week detailed descrip- tions were given the various continuous casting units now commercial pro- duction undergoing exten- sive experimentation, namely the Junghans, Williams, El- dred, Poland, Aluminum Co. America, and other proc- esses. The end product such machines either billets ingots. Herein, the descrip- tion recent work con- tinuous casting concluded, with detailed data recent machines turning out strip end product. Most this discussion centers the new Hazelett ring mill, although some details other meth- ods are included. with, and both the construction and performance this design has been previously described detail. (See Iron March 21, 1935; Oct. 15, 1936.) Essentially the mill not unlike the original Bessemer sketch re- produced page 46. There are two steel rolls, cooled externally with wa- ter sprays, between which liquid metal poured. With the rolls turning and pool molten metal maintained be- tween them, two continuous strips metal are cast (one each roll), the two being pressed together and given certain degree reduction the nib the rolls. the Scovill Mfg. Co. this type Hazelett casting-rolling mill produced substantial tonnages 12-in. wide, sound brass strip, having good physi- cal characteristics, and strips weigh- ing 3000 The metal was sound, and costs were low, but red stains frequently blemished face, due segregation the low- melting-point constituent the brass. This staining had serious effect the metal physically, but did make the product unsalable where high fin- ish chromium plating was required. Sometime later the Crown Cork Seal Co. used Hazelett machine for the production aluminum strip. Here again large quantities strip 24-in. wide were produced, sound and curate gage. But still there was seg- regation (copper) difficulties. Hazelett then came the conclusion that the rolling alloys had its dis- advantages because segregation in- herent the operation this type casting-rolling mill. This segregation came about because irregularities cooling, due folding the frozen films contact with the rolls, which, turn, was due the fact that the frozen film did not travel exactly the same speed point the roll. the pass, where high pressures were applied the partially chilled alloy, the lower melting point constituents the alloy were forced into the places least cooling and least pressure. The most refined work one these casting-rolling mills was com- pleted recently the American Meta! Co. conjunction with the Scovill Mfg. Co. this work, efforts were confined pure metal—copper— which, course, would not subject segregation. There was devised trolled atmosphere the furnace and runners, means shrouds about the mill itself, order produce oxygen-free copper strip. The metal obtained (so-called OFHC copper was excellent from metallurgical standpoint. summarize, therefore, the cast- ing-rolling mill had fairly low speed, the order ft. per min.; there were segregation difficulties when rolling alloys; thin gages could not produced; and for the rolling carbon and alloy steels the problem roll maintenance was quite serious. Hazelett came the conclusion that solve the problem segregation the metal should poured first one cooling member and allowed chill almost throughout its thickness and then surface-rolled chill and com- press the very small film unsolidi- fied metal. this, was neces- sary form the bath one surface instead between two rolls, there- tofore. This achieved the new type ring mill pouring molten metal the outside large rotating This surface first has de- gassed, order get sound metal, and then high rates for con- tinuous production. This achieved the type mill sketched page 46. will noted that the mill es- sentially vertical steel ring supported horizontal rolls, the top one which driven. Co-acting with the ring topping (or surfacing) roll which may driven. The surfacing roll floats (under pressure) top the ring, and the molten metal poured pass between the two. distributor serves conduct molten metal from source supply point between the roll and the ring. With the rolls motion fluid metal introduced into the distributor, the metal solidifies between and ring and, after following the latter for very short removed continuous strip speed about 500 ft. per min. This type mill pro- duces very thin strip, say 0.02 in. thick, and widths in., although considerably wider mills ized. The molten metal poured the rinz gives the major portion its heat fusion thereto. This ring not pensive make, and can ft. diameter, desired, and presents such very great amount cooling surface that high speeds and high pro duction can obtained. order avoid large amounts scrap the beginning the heat, necessary de-gas the ring pre-heating it. For upper roll, surface the prod- uct, internally cooled roll has been used, having extremely thin walls, low in., shrunk splined shafts. Even roll small in. diam- eter with in. wall will run continu- ously the high speeds without heat- ing up, sufficient quantity water sufficient pressures forced through it. The power required this ring = mill not large, running only hp. per foot width, depending the metal being rolled. the older type casting-rolling mill the power was the order hp. per foot width. The ring mill uses side dams control the width the strip—the width controlled the rate metal flowing from the distributor. The writer observed several heats metal poured this ring mill. One casting was strip in. wide the rate about 500 ft. per min. The edges this strip slightly ragged; the edge gage was 0.019 in. and the center gage was 0.021 in. Sam- ples the metal as-cast showed the following analysis: 73.15 Cu, 0.20 Pb, 004 Fe, 0.003 Ag, and 0.005 Ni, the remainder Zn. Samples were and showed maximum 39,600 Ib. per sq. in., minimum 34,200 per sq. in. and elongation in. and per cent respectively. These tests were not entirely satisfactory the specimens broke the fillets. Fur- ther samples were annealed for hr. 1380 deg. and testing showed maximum tensile strength 37,200 per sq. in., and minimum 33,- 900 Ib. per sq. in., and elongation and per cent respectively. These were good breaks. given from the microscopically, Samples were then cut strip with results photomicrograph page 47. The inside surface the sheet as-cast continuous casting ring mill the Hazelett laboratories. The topping roll and section the ring may seen See sketch next page. THE IRON AGE, April 1940—45 ¢ 4 4 9 wh and — original sketch for the continuous rolling strip from liquid steel. Norton's machine (1890) and Hazelett's machine (1925-35) were very similar over-all opera- tion, although minor construction details differed. 2 Electric radiant roll preheater sketch Hazelett's new ring mill for the continuous casting liquid metals. Stainless steel strip in. wide has been cast this type mill speeds approaching 500 per 46—THE IRON AGE, April 1940 had structure between cast and rolled one and was The outside surface as-cast had structure more nearly approaching rolled structure. The unannealed showed large variation structure which was removed large degree annealing. After annealing, the strip was pickled and given reduc- tion 0.012 in. one pass. The cast, had somewhat darkly mot tled surface which disappeared after annealing and pickling, that after