The Iron Age 1943-07-22: Vol 152 Iss 4

IN IMPROV! fp ROLL MANU STEEL a 7 q y 4 € 4.00,000 Friends who will waiting give soldiers jobs While American industry intent winning the war, has obligation plan ahead—as the government doing —so that victory will not mockery those who won it. 400,000 machine tools built for war can the best friends our soldiers have when they return someday. these machines are distributed quickly and wisely from war plants peace plants, they can start turning EVER! out the goods meet dammed demand. And meeting it, pro- vide jobs without which that demand will dry and start depression. These machine tools are badly needed thousands American plants HARR whose tools are old, inefficient, wasteful. These newer tools would help such plants turn out goods lower costs—which broadens markets, Men makes workers’ jobs more secure, provides more good things life for people. Jobs and better living for all who will work efficiently isn’t that what everyone wants after the war? Then plan your machine tool needs now, that you will ready provide your share both those prizes peace. indexed thed Turret Lathes THE IRON AGE, published every Thursday the CHILTON (INC.). Entered second class matter November 1932, the Post Office Philadelphia under act March 1879. yearly North America and South America, Foreign $15. Vol. 152, No. WARNER BAUR 1 Johnson, Market Research Mgr. Vol. 152, No. July 22, 1943 Editorial and Advertising Offices 42nd St., New York 17, Y., Editorial Regional Business Managers Dollar Bank Versus Dellar 42nd St. East 42nd Guardian Bidg. 428 Park WARREN Microradiography Light Alloy Spot Welds 2420 Ave. Physical Properties Fiberglass Plastics War Finishes Dominate Electroplaters’ ° Executive Offices Chestnut and Sts., Philagelphia 39, U.S.A. Features OFFICERS AND DIRECTORS JOHN BLAIR MOFFETT, Secretary HARRY DUFFY CHARLES HEALE ° News and Markets Member, Audit Circulations Murray Bill Weuld Aid Prompt Settlement WMC Flayed for “Intolerable” Situation Will Italy’s Furnaces Assist Allies? er $soci usiness Papers Non-Ferrous Metals News and Developments Non-Ferrous Metals Prices; Scrap Prices. Iron and Steel Scrap News and 140 Comparison Prices Year. 142 Steel and Warehouse Prices South America and Semi-Finished Iron and Steel Prices 145 $8: Foreign, $15 year. Ore and Coke 149 — : q j q ° | a °° More and more are utilizing Mahon the fabricating welded plate parts and fittings. cent recognize the greater tages welded steel plate cranes. The bases which HIS duty work like this that WELDED STEEL BASE for superiority welded steel over LOCOMOTIVE CRANES the fact that Mahon ability and equipment produce it. — designed built teke the shocks and train not only the weight the crane—but the your product and advise you welded steel extra lifts and struction can advantageously Edi Region i ; ‘ 4 a Machine Bases and Frames and Many Other Welded Steel Plate Mos! ter port other has will ESTABLISHED 1855 ° fe) VAN DEVENTER President and Editor BAUR and General Manager DIX Manager, Reader Service Mews, Markets Editor...D. JAMES Editor.........F. Associate Editors MacDONALD BARMASEL BUTZNER BENEDETTO Editorial Assistants SCHIEN WILLIAMS BUTTERS Regional News and Technical CAMPBELL Pittsburgh 428 Park Bida. PHAIR Chicago 1134 Otis Bldg. MOFFETT Washington National Press BROWNE Washington National Press Bidg. Cleveland 1016 Guardian BRAMS Detroit 7310 Woodward Ave. OSGOOD MURDOCK Francisco Market St. Editorial Correspondents ROBERT Cincinnati PENLEY Buffalo FRAZAR Boston HUGH SHARP Milwaukee SANDERSON Toronto, Ont. RAYMOND KAY Los Angeles JOHN McCUNE Birmingham ROY EDMONDS St. Louis JAMES DOUGLAS Dollar Bank Versus Dollar Sock HAT call hoarding, the accumulation excessive inven- tories, not always matter intent. some cases almost matter compulsion. The distribution pattern has good deal with it. did not have banks take and hand out dollars, but each person was his own depository, there would have thousands times more total currency printed order take care business and personal requirements. And this would true even dollars, like steel, made only one trip market instead many. The same thing true with regard foodstuffs, which, like steel other industrial materials, also make but one trip market. all lived miles away from the grocery store instead next door one would have buy our Wheaties the case instead the package. And this too would encourage excessive inventories awaiting use. the very vitally necessary endeavor squeeze two more million tons steel this year into our increasing war effort, the WPB putting great stress upon the reduction, wherever possible, inventories. large part the total additional steel going into supply expected from this source. One ton steel put use from existing inventory certainly worth two tons from future production from the standpoint war effect. this connection might well consider the part that the steel warehouse plays distribution. the early months the war, several million tons steel were taken from warehouse stocks meet war emergencies. result the ensuing shortage steel ware- houses many consumers felt necessary build their own stocks. Since one ton steel warehouse will probably do, given time, the equivalent amount work five ten tons scattered individual plants, the total effect inventory was doubt considerable. addition, CMP regulations giving steel producers the authority reject orders for less than minimum quantities has undoubtedly tempted many consumers place orders the mills for two three tons order obtain half ton needed material. Since the first the year there has been marked improvement mill deliveries warehouses. Generally speaking the supply now enables warehouses take care what under normal circumstances might considered fairly high percentage customer requirements. The drive inventory reduction will center upon the 2000 our largest steel consumers who, rule, buy direct from mills. However among the remaining tens thousands smaller consumers there probably higher percentage “overage” even though the total tons may not aggregate much. The specialized economic position the warehouse should enable reach effectively into these thousands smaller inventories, providing permit warehouse service function its most efficient basis. q , | — ° ° 1 ° ° | : j | 3 How the Spectrograph Helps Maintain Every open hearth heat run the Inland mills checked not only routine con- trol methods chemical analysis, but also special spectrographic laboratory. Inland was one the first steel mills America install and develop tech- nique for using the spectrograph con- trol quality. important advantage this method the rapidity with which tests can made. any stage during the working heat melter can have accu- rate check the chemical INLAND STEEL CO. Examination the emanating from the vaporization the steel sample electric arc quickly reveals the chemical content the sample, spectrographic film provides permanent record each Billion arrant Inland Quality Le: chri content within ten minutes after sample delivered the laboratory. Not only these frequent and rapid tests assure the uniform high quality Inland steel, but they also help maintain capacity produc- lass tion—a vital necessity this time war. The spectrographic analysis only one the many checks and balances used Inland the production steel—it lectri only one the numerous qual- ity control methods adopted Inland after rigid tests prove their practicability. his Offices: Milwaukee Detroit St. Paul St. Kansas City Cincinnati New York News JULY 22, 1943 Drastic switch can manufacture from tin plate lacquered stock likely will war's end the result American Can's acquisition the Diller machine flash (butt) welding can bodies speeds exceeding those for conventional and soldering. Diller, young free lance engineer, turned down $500,000 out payment favor much smaller spot settlement. also has worked promising new welding scheme for airplane propellers, for which egotiating. probably won't long until Anglo-American agreement common uniform sheet and wire gages substitutes direct measures decimals inch for the gage Sizes now used each country. Redar production has been hard pushed meet demands because shortage dies for drawing 0.00035-in. nickel chrome, copper and aluminum wire. 12- Bpindle, high speed vertical machine for diamond drilling, developed for which were bought the government, being leased WPB's diamond die die makers, with deliveries soon made. Fad thinkers held forth last year how nobly the home front could take sacrifice inconvenience only hesitant Government would make the demand. Now the view sacrifice unnecessary. The next stage will that sacrifice positively likely end fostering European communism and feeding Hottentots. Government officials pooh pooh the necessity drives for scrap (roofs, doorknobs, etc.). Not only there current glut several pounds brass rod turnings, but the Army and Navy have storage tens millions pounds fabricated brass, moving slowly not all. Hopes spectacular ore pocket Lake Superior area property not now being porked were raised high after single test hole drilling few weeks ago Cleveland Iron Co. Further drillings are being made. The detinning plant construction program definitely out, with contracts for all plant cancelled. Reasons are: (1) trouble now getting tin from the Congo; (2) not enough tin can recovered from electrolytic tin plate continuance the program. can making order will modified soon force use more electrolytic tin for certain can ends. Such use now Lend-Lease has just placed order with National Tube for more than 3600 tons chromium tubing for shipment Russia during the rest this year. The tubing, oil refining, represents the largest order this type ever placed. According one the largest the end 1943 there will planers last industry this country until 1955. type resin plastic laminated with high strength woven lass fiber showing considerable promise for number airplane structural Those companies putting electric furnace capacity since 1941, which never before capacity, have been Andrews Steel Corp., Youngstown Sheet Tube, Byers, and Babcock Wilcox. Bethlehem, Cyclops, and Ford have made furnace additions during the same period. German fighter planes are loaded with armor plate, vindicating British in- such pilot protection several years ago. The 210 carries 900 lb. around engine, pilot and system, the armor accounting for per cent total weight. has set ceiling price charcoal made from hard wood $33 New York and area; $27 Tennessee and Arkansas. These ceiling prices are higher than for charcoal iron. Charcoal currently imported from Cuba runs about $90 ton. The British Typhoon and the American Thunderbolt have been distinctively colored ground crews will not confuse them with German Fw's. Germany probably will copy coloring, the past deliberate effort has been made imitate Allied for instance, rings around the black crosses, white vertical stripes tail yellow stripe along the leading edge certain fighters, etc. q ut Microradiography ODERN methods manufac- ture and research, especially the fields light alloys have advanced rapidly under the impetus war necessity that not surprising there some confusion regarding the application and correct techniques the various X-ray meth- ods examination now available assure soundness and safety. Clearly distinguished tech- nique, application and interpretation are ordinary macroradiography and the new method microradiography. The former involves comparatively massive specimens and photographic registration which has the same size the irra- diated portion the specimen (en- largement ratio 1:1). The radiograph delineates discontinuities, etc.—with negligible absorption for X-rays comparison with the solid matrix. such case there possibility distinguish- ing the microstructure such grain boundaries and phase precipitation sound portion the matrix which appears, therefore, homogenous single phase regardless the wave- length the X-ray beam. Thus the use X-ray tubes with different tar- gets, and the distinction between gen- eral “white radiation” and charac- teristic K-series rays becomes minor significance long the pene- trating power the X-ray beam, controlled voltage, compatible with the effective atomi¢ numbers the chemical elements the specimen and with thickness. Both these factors are involved the fundamental ab- sorption law: Where Initial intensity the X-ray beam Intensity after passing through thickness Absorption coefficient, which depends upon the wavelength and also the atomic number the chem- ical element 2.7128, the base the natural system log- arithms. unfiltered X-ray beam, contain- ing general radiation only, teristic radiation the particular target metal superposed the gen- eral radiation, has “effective” wavelength, which means that absorbed the same way some particular ray which strictly mono- chromatic. Thus not surprising that the radiation from tungsten target tube, commonly used for steel and heavy metals, should also ap- plicable light alloys shown Woods and who experimen- tally demonstrated that optimum volt- age more important than target metal the production good radio- graphs. the other hand, microradiog- raphy presents entirely different problem. The specimens are only few thousandths inch thick; the radiograph larged 300 diameters, and radiation analysis unfiltered radia- 2—Section swaged duralumin propeller. (Negative tion from machlett molybdenum target X-ray tube, 40,000 volts and milliamp. > Blackening, oO Ww 0.1 44—THE IRON AGE, July 22, 1943 print, Microradiograph made copper charac- teristic radiation. Light regions are delinez cessful guish, (13) sep ext have efficier techni selecti passin chrom sectio image the tered with emuls able. detail ture indie | ve” ap- len- olt- delineates microstructure. suc- cessful, must possible distin- guish, for example, between magnesi- (atomic number 12), aluminum (13) and silicon (14) they appear separate phases the alloy even extremely dispersed form. They have closely similar absorption co- for X-rays. Thus successful technique depends upon the careful and regulation X-ray wavelength. Sample Must Thin Briefly, the technique consists passing X-ray beam carefully selected wavelength, preferably mono- chromatic with one wavelength greatly predominating, through thin section the alloy, which need not highly polished. Since there are lenses for enlarging X-ray image directly, the small radiograph the exact size the beam regis- tered special photographic film with very fine-grained Lipmann emulsion, which commercially avail- able. This “spot” which the finest detail recorded then photograph- enlarged 300 diameters Microradio- graph (a) dura- lumin and (b) duralu- min containing Mg. prints, Copper radiation. Left exhibits cavities containing many cases inclusions seg- Alloy right contains con- Compare with Fig. for the characteristic na- ture the dark regions, indicating low absorp- tion. ° Noyes Chemical Laboratory, University Illinois, Urbana, tiny section photographically enlarged several hundred times delineate microstructure. Wherein conventional radiography, the wavelength the X-rays are little importance, the distinction between rays from different types targets must made when studies grain boundaries and phases precipitation are being made with microradiography. this report, the authors use their chief example the analysis sectioned aluminum spot weld. The method may coordinated with diffraction analysis iden- tify phases and confirm such analysis may made from micro- radiographs. without loss essential detail from graininess. The present authors have published since 1939 several the field the microradiography, which deal exhaustively with the the- ory, the methods making such ra- diographs and also with the possible interpretation. true, however, that there may tendency think microradiography routine con- trol method—rather than method improving devising production methods. For light alloys the alum- inum and magnesium types, micro- radiography requires specimens about 0.010 in. less thickness. This obviously makes the method unsuit- able for routine control except ex- ceptional cases where thin sheets material are being prepared. the other hand, may used much r 4 8 = » ° ° the log- ain- "ac- ° ° ‘get dio- q log ya the en- > THE IRON AGE, July 22, 4—Microradi- negative print Mg-Al al- loy (12 per cent acteristic radiation. (200x). Compare with Fig. 3(b). a: microscopic metallography, and (0.002 in.) satisfac- since the microradiograph applies 3-dimensional specimen while the etched surface essentially 2-dimen- sional, will found give addi- tional information which can considerable value. Effects heat treatment, ageing, cold working, etc., all may expected show certain phenomena the microradiograph. Excepting the time used prepare the specimens, and with light alloys such indicated above, the micro- radiographic exposure will rarely take more than min. most. Some magnesium alloys can examined dent that the time factor not too important. Even 46—THE IRON AGE, July 22, 1943 torily examined min. with Machlett cobalt-target X-ray diffrac- tion tube. Fine Grain Film Necessary already mentioned, extremely fine grain film necessary for radio- graphs this type. Gaevert Lipmann emulsion has been used this labora- tory for considerable period time. Eastman 548-0 plates have been found satisfactory and recently excellent re- sults have been obtained with East- man 548-0 film. All the illustra- tions this paper have been made with Eastman film, using copper ra- diation (unfiltered) from Phillips Metallix diffraction tube, with expo- sures the order min. The exact technique making patterns been previously described has the theory dealing with the obtained and the necessary One the most interesting and valuable extensions raphy, also described detail the present authors previous technique. X-ray tubes with different targets such chromium, iron, copper, molybdenum, etc., may op- erated that one wave length, that the ray, each element, pre- dominates. Thus each tube produces its own characteristic radiation and wavelengths may selected will the choice target. specimen for microradiographic examination may have several constituents, each with different absorbing power. De- pending the absorption coefficients, two more these may differen- tiated rays from one target, and two three others identically the same spot may differentiated rays from another target. For example, sample bronze first investigated with molybdenum radiation (0.7078 Ang- strom units). the negative print lead only appears white areas. With copper target, lead and tin both appear the negative print. Thus any chosen area the graphs may compared show the distribution tin the general ture. the molybdenum target mi- croradiograph slight evidence the tin areas appears gray, from which may concluded that there some solid solution tin lead that intermetallic compound formed. Thus this differential method any LEFT alloy spot weld using copper K-alpha characteristic radiation. (Negative print, 28x). Dark regions correspond low absorp- tion the X-ray beam. BELOW 5(b)—Specimen from aluminum alloy spot weld, cut out for microradiographs [Figs. 5(a) and and diffraction patterns (Fig. 7). The dash circle shows the X-rayed area was "blown up" the microradiograph. Section was sliced about 0.01 in. thick. Electrode Electrode ~k, analy cient. % lyhde | cut that sliced — Fis. microradiographs showing the spot weld structure Copper radiation. Compare with diffrac- tion patterns Fig. complex alley may the selection the proper tadiation depending the differences tabulated linear absorption coeffi- Characteristic Radiations rh recorded from mo- ‘target X-ray diffraction tube, for example, obtain such graph from microphotometer shown Fig. The graph goes almost the short wavelength limit, but this obscured due halation from the undiffracted X-ray beam. This method radiation analysis tends enhance the part the radia- tion which here indicated gen- patterns the three layers aluminum spot weld; filtered copper radiation, eral radiation respect the char- acteristic radiation which essentially controls the expo- sures. spite this enhancement will noted that the intensity the almost pure characteristic K-alpha ra- diation practically completely drowns out these background effects. This would not true heavy filter THE IRON AGE, July 22, 1943—47 lso were placed before the window the diffraction tube, and used filter out the softer radiation provided the volt- age considerably above that re- quired just excite the characteristic rays. Thus very thick sample will not make effective use such character- istic radiations all, and any effects observed would due the harder more penetrating general radia- tion. This accord with the gen- erally understood principle that the higher percentage inhomogenous X-ray beam absorbed, the harder the transmitted radiation. This may well the case macroradiography, and may problem this field. Another way illustrating the manner which the characteristic radiation completely drowns out the general radiation examination ordinary diffraction pattern aggregate small crystal grains, indicated Fig. Here the radia- tion responsible for each intense line any effect due general radiation present the beam which not negligible comparison with the sharp characteristic lines. Simple filtration with characteristic filters will even remove some the lines and leave only the most intense alpha doublet. While not the subject this paper, the X-ray diffraction technique mentioned because supplements well many the microradiographic studies. This depends upon the fact that crystal, virtue the per- fectly arranged atoms equidistant parallel planes, acts diffraction grating for X-rays which impinge narrow pencil rays defined pinholes the crystals. Thus pat- tern photographed which charac- teristic the ultimate crystalline structure the given material and thereby identifies the specimen. Each separate crystalline constituent pro- duces its own pattern spots lines. The pattern also distinguishes the texture the is, aggregate (or powder) Fig. whether there preferred orienta- tion grains from cold working. The importance the characteris- tic radiation lies the fact that wide range specific wavelengths can selected and may generated using diffraction tubes with different target metals; and that their quality (softness) wavelength not al- tered with change voltage the diffraction tube. Thus copper char- acteristic radiation corresponding voltage about 8970 (8.97 kv.) will 48—THE IRON AGE, July 22, 1943 retain all properties the radiation generated the minimum voltage even though 50,000 volts are placed across the X-ray tube, the only change being that the voltage increased the intensity the copper radiation will increase almost the square the voltage difference (volt- age tube less characteristic volt- age). The use selected characteristic K-alpha radiation the preparation successful microradiographs with excellent contrast illustrated with number examples. swaged duralumin airplane propeller, showing the orientation the segregations—the high concentration the copper this crystalline segre- gation accounts for the relatively high absorption observed. Fig. 3(a) the microradiograph some Alcoa 295 alloy showing curious cavities which inclusions have tended fill up. Fig. 3(b) represents microradiograph 220 alloy, con- taining considerable amount mag- nesium. The dark shadows are ap- parently characteristic such alloys may noted comparison with Fig. made from specimen contain- ing per cent magnesium and the remainder aluminum. Application Spot Welds Spot welds light alloys are considerable interest and importance the present time. Microradiographs present remarkable details the structure (in the micro sense) far beyond the scope the best spot-weld radiographs which can depict only the gross macro features the junction. For example, Fig. 5(a) shows microradiograph diame- ters taken through half section aluminum spot weld. sketched Fig. 5(b), vertical section about 0.01 in. thick was cut through the spot weld nugget. Surprisingly enough will noted that there are least three distinct types layers present single sheet. Fig. 100 diameters emphasizes the differ- ences structure. Surface must very high aluminum since its absorption re- markably low. Layer contains large amount segregated with the crystals all oriented right angles the direction the weld. The central layer which found both sheets shows cracks and channels matrix which lacking segre- gated CuAl.. The separation the two inner layers and extremely sharp, and may noticed that the cracks from the central portion the weld tend turn and follow this boundary. This, well the ab- sence the one layer, cate clearly that there able tension strain the boundary these two layers. The layer probably quite soft, while the tral layer must contain considerable copper solid solution and may expected hard. This analysis largely confirmed means diffraction patterns the layers shown Fig. The diffraction effects the aluminum are shown, since the pattern due the very faint and exposures were not sufficiently long empha- size this portion the pattern. Layer corresponds pure aluminum, and shows essentially smooth rings, cor- responding work hardening, least approximately. Layer shows ab- sence strain with many single crys- tals each reflecting produce spots the positions the aluminum dif- fraction whereas layer shows distor- tion and reflection spots angles other than the diffraction (strain). Limitations Technique should noted that light alloys are not the only material suitable for this type investigation. bone structures, even biological tissue materials may examined this manner. The greatest utility, how- ever, unquestionably lies the greatest handicap the method fixed the grain size the emulsion used—at present only about 300 diameters can obtained. The ad- vantages are that etching, fine polishing, etc., are needed, and that the picture obtained three-dimen- sional, indicating the actual structure the metal rather than surface fects, which may conceivably tered the cold working associated with any polishing process. The authors wish acknowledge the courtesy the Taylor-Winfield Corp. furnishing most the ples used for the microradiographs this paper. References Woods and Cetrone, THE IRON pp. 52-58, March 25, 1943. Clark, Photo-Technique, Dec., 1939. and Shafer, Trans. Amer. Soc. 1941, 732. Microradiography,” Gross, Ind. Eng. Chem., Anal. Ed., dustrial Radiography, vol. No. (1942). substitut that met. arses will sti tations sim The few hou ten exa Alloy lrons,”” sued ing duct gtaphs Elong: the sam- ONSUMERS alloy steels the AISI and types may frequently asked accept substitute steels slightly different content with the assurance that hardenability requirements will met. But the question naturally “If quench and temper this steel the required strength, still get the ductility the specifi- simply get wondering: “Just vhat the effect carbon content the ductility structures from the tempering The answer can obtained hours labor the many SAE tempering charts for particular example, “Nickel Alloy Steels,” Alloy Steels,” “Vandanium Steels and and numerous pamphlets is- the American Iron and Steel However, the information not been widely spread the available form charts show- ductility plotted against carbon Since the spread published property figures rather trend. save others the few involved, the accompanying are submitted. and reduction area the tensile test are shown ; an There has never been much data plotted show directly the effect carbon content the ductility steels quenched and tempered given hardness strength. The author herein at- tacks this problem semi-statistical manner, using original data (although controlled experiment would interesting). This work should interest those metallurgists today confronted with bewildering list substitute steel. ° ° MALCOLM HAWKES Instructor, Department Metallurgical Engineering, Carnegie Technology, Pittsburgh ° ° ° function carbon content. Fig. average, “expected” values for steels fully quenched then tem- over many heats. These data were pered back 150,000 Ib. per. sq. in. from the sources listed previously. tensile strength. Fig. shows most Data from the work Janitzky and the same steels 200,000 per Baeyertz (See ASM sq. in. tensile strength. With few 515) are indicated range the exceptions every point the short horizontal lines 0.30 carbon represents data from charts, based and 0.42 carbon. (Janitzky and Tensile strength 150,000 w 2in. Elongation 0.10 0.20 0.30 040 0.50 0.60 0.70 0.80 Per cent carbon, THE IRON AGE, July 22, T- n- ‘he the res ha- yer and ast ab- dif- gles ngle loys eels, ssue this how- The d is lsion 300 fine that men- ° Tensile strength 200,000 per Reduction area Elonaation 2in. 0.30 0.40 0.50 0.60 0.10 0.80 Per cent carbon Baeyertz combined data from 0.40 and 0.45 carbon steels.) Most points represent test bars fully quenched out before tempering. That is, they were hardened throughout and did not consist hard case and soft core. Possibly, some ex- ceptions this occur the low- carbon low-alloy ranges; however, obvious exceptions such the shal- were immediately detected their poor ductility and were, course, because the graphs are not intended hardened steels with mixed micro- structures. When first plotting these graphs, individual alloy types were indicated separate symbol, but The types are not identified Figs. and will suffice say that all the principal SAE types, several other alloy steels for similar uses, and four steels from the 8000 series are included. Yield strength values the same sources were plotted against carbon content the same way, but are not submitted here, because the lare spread published data con- vincing that, the average, they are unreliable. For example, one standard source gives 128,000 lb. per in. the average yield strength SAE 6150 tempered 150,000 per sq. in. tensile strength, while equally reliable source gives 145,000 Rust Resistant Finish for Metal coating for metal prod- ucts known Armor-Vit, which essentially alkali alumina sili- cate, has been developed the Chi- cago Vitreous Enamel Product Co., Cicero, Ill. After the application Armor-Vit ordinary spraying equipment dipping method, the curing treatment, best accomplished air-circulating oven with proper temperature con- trol and capable heating from 750 800 deg. F., combines the ingredi- ents the coating into hard, heat- resisting finish, insoluble boiling water and resistant most acids and alkalies. Armor-Vit applied either one 50—THE IRON AGE, July 22, 1943 two coats 0.0005 0.0010 in. thickness. For its application, the metal cleaned ordinary cleaning methods—alkali cleaner, acid pickling and neutralizing. Sandblasting recommended for cast iron. This coating has been tested and 200-hr. salt spray test, extended weatherometer tests and other acid and alkali tests. Impact and abra- sion are also endured surfaces treated with this product. Armor-Vit applied ordinary steel test plates has been heated 1200 deg. F., then quenched cold water, without fail- ure the coating. lb. per sq. in. the yield The frequency such indicates that considerable care exercised testing for strength( for example, selection standardized speed testing, tion sensitive strain measuring de. vice, and care alinement men the grips get axial loading), Hardness data were also plotted the same way but showed signif- cant trend. The with tensile strength appeared valid over the range studied. Returning Figs. and the im- portant practical conclusion the average, there should expectation trouble meeting due- tility specifications because 10-point change carbon content. exception would the case where there already few rejections for low ductility and sary higher carbon steel, duction area slightly more sen- sitive changes carbon content (note greater slope curves) and other factors (note greater spread). This true effect and not merely the result the used plotting; the same scale used for both properties, because rect the nearest one per cent the scale for both properties the respective ranges will found out when the tion area figures come in. Fig. would appear indicate that high strengths low carbon steels lose their slight advantage tility over the higher carbon grades. Data were also collected for tensile strength 100,000 lb. per sq. in., but showed the same trend Fig. and hence are not reproduced here. with ARMOR-VIT. The other half (left) bears finish whatever. This badly rusted half the sult exposing the pipe the weather five months. considered. other words, something goes wrong, den: promise The weigh order chara local flight The manh all faces. tautical ment large nolds, Many bein must de- peci- ing), ation Valid that, vhere for eel, ntent and scales that steels rades. ensile but Fig. here. bears "0 the sther for Properties aviation industry vitally high strength, low density materials which show This interest exists be- the following reasons: need for the further reduction weight all types airplanes order obtain better performance characteristics. The need for increasing the rigidity all thin gage sections reduce local failures resulting from vibration and maintain contours under all flight conditions. The need for reducing the number manhours required for the tooling, fab- and final assembly air- frames. ~ need for improvement the over- all smoothness all aerodynamic sur- faces. generally agreed among aero- engineers that the develop- low density structural plas- material, capable being molded assemblies with inexpensive would help satisfy the needs above. The word “structural” implies that the plastic will possess certain minimum properties. For structural airplanes, the strength-weight and other mechanical proper- must compare favorably with values the commonly aluminum alloys. Many new resins have recently been and doubtless ithers will emerge from the numerous laboratories. These resins are being cast, and laminated with large fillers, organic and inor- fibrous fillers—woven fabrics, fabrics and the like. has exceedingly difficult for the choose from among these combinations any one for specific application. The Fiberglas Laminated Plastics Use high strength filler material like fabrics woven from glass fiber conjunction with new type thermo- hardening resin results laminated material that may used advantage many airplane structural applications. The ability mold large contoured assemblies with little pressure should show substantial saving cost and time required fabricate many assemblies now made sheet metal. This report was recently presented before the semi-annual meeting the American Society Mechanical Engineers Los Angeles. CECIL ARMSTRONG Senior Research Engineer, Lockheed Aircraft Corp. need exists for reliable engineering data plastic materials that intelligent selection material for specific application can accom- plished. Considerable being made this direction the joint efforts the Army, Navy and the plastics industry, but much re- mains done. Among the new resins which have become commercially available (mili- tary requirements first, course), there are several thermohardening resins which are unique that external pressure required during the process molding plastic part. These new resins may used com- bination with high strength filler ma- terials produce low density, high strength laminated plastics which soon may fulfill some the needs enumerated above. Use Pressure” Resins produce laminated plastic article from one these “no pres- TABLE continuous filament cloths used for laminated test specimens.* NOMINAL THICKNESS WT-OUNCES PER PER INCH + 007 DATA SUPPLIED OWENS-CORNING FIBERGLAS CORPORATION THE IRON AGE, July 22, the \ i Fig. designed test Fiberglas laminates comparison. sure” resins, one more layers the filler material may wrapped around draped over mold. The filler material may saturated with the liquid resin either before after placing contact with the mold. The laminate then cured (hardened) application heat. Curing tempera- tures seldom exceed 240 deg. The curing period may require from min, hr., depending upon the re- quirements the particular resin, the thickness the laminate and the heat conductivity the mold. smooth, glossy surface desired, non-porous cover sheets, such Cellophane, may used. Parts having intricate shapes and Unit 1000 psi 52—THE IRON AGE, July 22, 1943 and double contours may necessitate the use light pressure (0.1 lb. per sq. in.) keep the impregnated fab- ric filler material intimate contact with all surfaces the mold and prevent free resin from accumulating localized spots. For application these pressures, the use thin trans- parent films inexpensive thermo- plastic materials has been found more suitable than the use expen- sive synthetic rubber hags. Because the fact that pressures are low, molds may simple, light weight, inexpensive. The primary re- quirement that they made correct dimensions and contours. Stress-strain values for various Fiberglas laminates tested tension. See Table for physical properties and end- point values corres- ponding the lami- nates designated. tensile strain, in. per in. Indicates failure preliminary study the limite amount available data, mented various laboratory indicated that the MR-1A resin’, laminated and dis. Manufactured Marco Co., Philadelphia; tributed Swedlow Aeroplastics Glendale, Cal. laminated with certain the glas fabrics, possessed better cal properties than any the mercially available resins. Accordingly, modest tes program was undertaken the heed Structures Research Laboratory, Results reported are typical thus far obtained. Physical Test Program Table gives specifications filler which were used the preparation materials flat sheet laminates, from which test specimens were machined. Tension and bend test specimens were prepared and tested ance with the General Federal cation for Organic Plastics, dated December Bearing stress-deformation data (See similar the one developed the University Kansas.’ Ultimate hear ing stress values were obtained BER ard Stock Catalog, Superintendent Documents, Washington. Bearing Strength Plastics and Ply wood, James Bond, Trans. ASME. January, 1943. test specimens 2.50 in. wide, with 0.124 in. diameter holes centrally cated edge distance 0.375 The small compression test were supported and tested Jig designed Bonza the Lock heed structures research This shown Fig. The specimens were tested without special preconditioning. tests were conducted the Triplett Barton Physical Testing Burbank, Cal. Test Results Typical results are given lent weight base, are compared with corresponding values two The num alloys Table _ ur _LENG | ™ DIREC TANGE ULTIM DIREC YOUN __DEFO) MANA SPAN | TANG NOM St @ / ABOVE data 3—Stress-strain values for the same laminates Fig. but tested compression. (See Fig. for Deflection center, in. ion RIGHT See also Table pecifi- ixture TABLE PHYSICAL TEST RESULTS-MR-IA FIBERGLAS LAMINATES ven TANGENT PROPORTIONAL LIMIT 41,000 45000 {7000 19000 spec ULTIMATE BEARING STRENGTH, 32,100 38,500 34,800 34,600 THE IRON AGE, July 22, 1943—53 When 4 | ' 4 strength properties the aluminum alloys were computed from values published the December, 1942, edi- tion “Strength Aircraft Ele- ments” ANC-5. Attention directed the fact that these laminates are anisotropic, resulting from parallel stacking cross-stacking (alternate laminae ori- ented right angles) unidirec- tional materials, such OC-63 Fiber- glas bidirectional materials, such are listed Table Results shown Table were obtained from specimens cut parallel one the two principal directions the lami- nates. Preliminary tensile tests made from specimens cut deg. with the stacked MR-1A Fiberglas laminates exhibited ultimate tensile strength and tensile modulus values per cent lower than corresponding “with grain” values. Tensile tests made room tempera- ture from unfilled cast MR-1A resin (specific gravity 1.2) indicated average ultimate tensile strength 6200 lb. per sq. in. and average tensile modulus 370,000 per sq. in. The following data other proper- ties the MR-1A Fiberglas laminates were supplied the Swedlow Aero- plastic Corp. Methods testing were stated have been accordance with specifications: Impact strength, notched Izod, Ft. Lb./In. notch 100 Ultimate shear strength, Ultimate compressive strength, Moisture absorption, per Gasoline absorption, per cent Burning rate, In./Min....... Hardness, Rockwell ......... 71-107 Hardness, Barcol Impressor Heat distorition, deg. F..... 300-350 Coefficient linear ex- pansion, per Deg. F... 2.7-5.2 Fatigue and creep test data have not been determined. 5—These tests indicate the effect rivet shear stress yield Fiberglas lami- nates. See also Table interesting compare test re- sults basis pounds load per inch width per lamina with corre- sponding values the Fiberglas cloth. Directional Effects Note that for the unidirectional laminate (see Table Laminate No. 223) the ultimate tensile load per inch width per lamina 880 and note from Table that the nominal breaking strength the OC- Fiberglas 875 lb. For cross- stacked laminates the same ma- terial (Nos. 224 and 309) correspond- ing values 520 lb. were obtained; however, since only one-half the laminae were oriented parallel the direction the load, these values could expressed 1040 per in. width for each lamina oriented the direction the applied load. Similar comparisons may made ‘with laminates made from the woven fabrics. Attention directed the fact that both the thickness and density the laminate are dependent upon the relative proportion resin and filler materials. tension, most the load carried the filler ma- 3—Specific strength values fiberglas laminates. SPECIFIC MATERIAL TENSILE SPECIFIC TENSILE STRENGTH MODULUS BUCKLING MODULUS BEARING STABILITY RUPTURE STRENGTH 223 FIBERGLAS 224 1.450.000 309 FIBERGLAS 236 1,120,000 833000 280,000 1,060,000 362,000 ALUMINUM ALLOY ALUMINUM ALLOY Specific Tensile Strength Specific Tensile Modulus Buckling Stability Specific Modulus Rupture 495,000 tensile strength divided specific gravity = Tension modulus dwided by specific gravity Flexural modulus divided (specific Specific Bearing Strength bearing strength divided gravity 54—THE IRON AGE, July 22, 1943 Elongation 0.124 hole, in. that loading was discontinued terial. Two laminates, each contain- ing the same number laminae, but varying resin content might carry equal tensile loads, but because the greater thickness would have different ultimate unit stress and values. Examination the data will show that the resin content (low resin con- tent results high gravity values) for optimum ties will not result optimum bend and compression properties. This fact may demonstrated comparing data obtained laminate No, 224 with corresponding data obtained laminate No. 309. | Cost Limitations The present high prices Fiber glas cloths impose serious limitations the use these materials simple structural applications. Many high strength organic and fibrous materials which recently have been developed ones known the developmental stage may offset this limitation. Moreover shapes formed from flat metal sheets with expensive dies drop hammers hydropresses followed manual assembly these parts, the use suitable plastic material can cost and valuable manhours duction time. Bonza for his assistance the conduct certain the physical tests the compilation test data which are included this report. siderati ation, the ing” word; inally pene steel The made “blacki sodium also hasten ture accord 275 the pendir under the Vary finishe ing The plai ficient gas, Into 388,000 11,700 cause Steel” was paper read William Price Jr., Mitchell-Bradford Chemical Co., who explained that the process under con- sideration involved the chemical cre- ation, relatively low temperatures, the black magnetic oxide iron, Fe,0,. This treatment not “plat- the common sense the dimensionally additive the orig- inally untreated piece steel. penetration into (without any di- mensional changes) the surface the steel depth perhaps 0.0001 in. The bath normally made mixing one number proprietary formulas, “blacking salts” with water. These salts are fairly high caustic, sodium hydroxide, content and usually also have other oxidizing ingredients their make-up for the purpose hastening (and reducing the tempera- ture for) the oxidation the iron accordance with the equation: Bath temperatures ranging from 275 310 deg. are recommended the producers these salts, de- upon the individual formula under consideration. Concentration the “salts” the blacking bath, will finished bath solution, again depend- upon the particular salt used. The equipment required consists steel tank supplied with suf- source heat the form pressure steam electricity. Into this tank are placed the blacking salts and water, properly tioned; sufficient heat applied Cause the solution boil, and the bath then ready receive work. Work given the black oxide Black Oxide Treatment War Finishes Dominate Electroplaters Convention this, the fourth and final part the report the. American Convention Buffalo last month, unsolved electro- plating problems are summarized, and papers protecting steel with blackening non-ferrous metals, Hull Cell technique, radiant heat and control devices are reported. treatment should chemically clean though were plated. Work may done baskets, wires trees specially designed racks. Work done baskets usually requires that the baskets shaken disturbed once twice during the blacking operation, uncover any otherwise unreachable surfaces the action the bath. Because copper, tin, zinc and other non-ferrous metals may inhibit poison the blacking bath, all con- tainers and implements used the bath should only steel. The work should kept the bath for about min. Proper concentration the bath usually judged the color the emerging pieces. gray color will ordinarily indicate the need for more salt the bath. Laboratory chemical test control the bath concentration would difficult procedure and, from experience, unnecessary. Immediately after the blacking op- eration, the pieces treated are very thoroughly rinsed free from caustic. Pieces containing folds, crev- ices blind holes may, not thor- oughly rinsed, show whitish salt crystallization these places, for the bath supersaturated solution room temperature. Following the rinse, the work subjected dip one many types wax oil. These may petroleum hydrocarbon waxes waxes which emulsify with water, so-called soluble oil may used conjunction with eight parts water. Some manufacturers blacking salts recommend blacking two steps and two blacking baths, the first bath usually operating slightly lower temperature than the second. Other manufacturers call for single bath immersion. The very thin film the black magnetic oxide iron does not af- ford much resistance. corrosion. However, the black oxide film has the very definite property either ab- sorbing adsorbing oils, waxes, etc., the point that combination the black oxide and the oil wax film produces rust corrosion resis- tance which substantial compari- son with steel alone, with steel coated with these same oils waxes. Properly handled, the black oxide film makes excellent bond between steel and subsequent applications paints, enamels, lacquers nishes. Black for Non-ferrous “Blackening Non-Ferrous Met- als” Dr. Walter Meyer, Enthone Co., covered class work important the war program for many reasons, including reduction glare, increase corrosion protection, chemical non- reactivity, identification formation bases for organic finish- ing. Most blackening nickel has been done the deposition some other THE IRON AGE, July 22, the ent vity end fact ring ber- jons for rural save j vhich metal coating upon the nickel sur- face, for example, black black chromium plating. typical formula for black chrom- ium is: Grams per liter 350 Barium carbonate ......... The solution operated room temperature and hence cooling fa- cilities must provided. The cur- rent density ranges between 1000 and 2000 amp. per sq. ft. Another method copper and then blacken this film. The coating thickness should least 0.00005 in. get adherent film copper, the activating treatment described Donald Wood should first used. This consists using the following solution: Nickel chloride oz. per gal.; hydro- chloric acid keep the solution be- tween and normal; anodes electrolytic sheet nickel; time min.; room temperature; current density 100 amp. per sq. ft. interesting method for the di- rect blackening nickel has been de- assigned Nickel Co. Knapp’s bath operates the range from bath recom- mended follows: Grams per liter Ammonium persulphate .... 200 Sodium sulphate .......... 100 Ferric sulphate ........... Ammonium thiocyanate .... Room temperature The blackening cadmium must done using solutions that de- posit some other black metal, oxide salt. For example: Oz. per gal. Copper sulphate, crystal .... Potassium chlorate ......... Sodium chloride ............ Temperature ...... 140 200 deg. Another method for blackening cad- mium use buffered molybdate solutions which are available com- mercially. High chromium and high nickel iron alloys are difficult blacken di- rectly and frequently must black- ened using the plating methods out- lined for blackening nickel. However, Clements Batcheller has been awarded patent for the direct blackening stainless steels. The ranges com- ponents are: Parts weight Oxidizing agent ...... Sulphuric acid (Sp. gr. Temperature ...... 190 210 deg. The oxidizing agent may al- 56—THE IRON AGE, July 22, 1943 kali metal manganate perman- ganate, manganese dioxide. The blackening aluminum generally done best producing heavy oxide film anodizing sulphuric acid solution and dyeing the film. Patents this process are held the Aluminum Co. Amer