The Iron Age 1940-02-01: Vol 45 Iss 5

Vanaging Editor Machinery Editor OLIVER VAN DEVENTER President and Editor Cc. S$. Editor Associate Editors BAUR Vice-resident and General Manager J. A. ROWAN Washington Editors L. W. Morretrr JAMES ELLIS Resident District Editors (CAMPBELL Pittsburgh JAMES Cleveland Editorial RIck-OXLEY London, England FRAZAR Boston MEYER Milwaukee SANDERSON Toronto, Ontario LEROY W. ALLISON Newark, N. J. Emerson Findley / Robert F. Blair § B VW Pei W. J. Fitzgerald § D. Dor L kK. ree H. B. BINGHAM Chicago SHERMAN Detroit Correspondents hopert G. McINTOSH Cincinnati FIDRMUC Hlamburg, Germany CHARLES Post San Francisco CLYDE ENNIS Birmingham hioy M. EDMONDS St. Louis TURNER, Buffalo DIN, Manager Reader Service IDVERTISING STAFF 621 Union Bldg., Cleveland Herman, Chilton Bldg., Phila. 1012 Otis Bidg., Chicago Hottenstein Leonard, 239 W Woodward Ave., Detroit 39th St.. New York Lewis, 7310 Ober, 239 W Robinson ? Warren, P. O Beach, Cal. 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M FAH RENDORE DUFFY FINDLEY News Editor Editor Emeritus Contents February 1940 Fool's Gold D.P.H. Measurements with Rockwell Hardness Tester. Flow Metals Flame Strengthening Copper Cast Mirror Strip with Carbide Rolls What's New Motors and Controllers High Tin Bronze Statistics Metal Working Activity the Assembly Line Washington News THE NEWS BRIEF Rate Activity Capital Goods Weekly Ingot Operating Rates Plant Expansion and Equipment Buying Just Between Two Products Advertised Index Advertisers Copyright, 1940, by Chilton Company (Inc.) 106 4 re . ada, 158 ; - = we Certified Steels also carbon, tool and stain- less steels. Partial list prod- ucts shown below. Write for the Ryerson Stock List, which gives data all Ryerson Certified Steels. Beams, Structurals Channels, Angles, Tees, Zees Hot Rolled Bars Bands and tivops Floor Plate Plates (over kinds) Sheets (over kinds) Alloy and Tool Steels Heat Treated Alloy Bars Stainless Steel Cold Finished Shafting Strip Steel, Flat Wire Mechanical Tubing Boiler Tubes and Fittings Welding Rod Rivets, Bolts, Nuts, Washers Concrete Reinforcing Babbitt Metal and Solder ? ” Company kwell Streets John 16th and Roc weer CHICAGO, Valuable FREE Guide Treatment Shipped with Thousands steel buyers are now enjoying the time money saving features the Ryerson Certified Alloy Steel Plan. They get carefully selected alloys which have all hard- ening factors (analysis, grain size, etc.) within very narrow range. With every shipment, large small, Ryerson sends accurate data heat treatment response, and chemical and physical properties. There need test, experiment order secure desired results. You too can have this valuable data. given without additional cost obligation. Simply specify Ryerson Certified Alloy Steels your next requisition. Immediate will made from large and complete stocks these accu- rately identified, known quality steels. Joseph Ryerson Son, Inc., Chicago, Milwaukee, Philadelphia, St. Louis, Cincinnati, Detroit, Cleveland, Boston, Buffalo, Jersey City. iil | Yj YY tpi Yj Yy Y yy ... THE IRON AGE ... FEBRUARY 1940 ESTABLISHED Vol. 145, No. GOLD ONTRAST the gold situation now, with that 1914 the start the World 1914, the United States had less than billion dollars gold, about per cent the world's monetary gold, which about one billion, three hundred million was Government hands. Today, the United States Government holds about billion dollars worth gold, between and per cent the total gold reserve and with none the hands our private citizens. 1914, gold was moving strongly London and Paris. Today, and for two three years past, gold has been moving the United States the rate from billion dollars per annum. Most being put back into the earth from which came, but Fort Knox, Ky., instead Alaska, South Africa and points East. 1914, all important countries the world were the gold standard. Today all countries are inconvertible paper standard. The hope and expectation our Government and our people that eventually all will return stand- the present flow continues, will shortly have the world's gold supply and the soil under Fort Knox will assay million times richer the ton than ard- the famed and fabulous Bonanza. But will then worth the labor digging up? The New Deal, through its clever advisers, found way reduce domestic and debts devaluing the dollar some per cent. But like many other New Deal white rabbits, that was not new. Our European debtors after the World War found way reduce their debts per cent repudiating the paper which was their payment for goods. fied After this and carry" war over, and after having bought our goods largely with gold, suppose the gold nations are forced abandon gold Where wouid that put us? 4 in = 4 Cage . 118, ity a the ski ing producer bumper bars, one the most intricate and exacting types bars rolled. The steel must clean and sound the size and shape must accurate. Although hot rolled product, un- usual degree surface smoothness required for plating, assuring perma- nent finish. Dearborn St., CHICAGO District Offices: TIN PLATE PLATES STRUCTURALS PILING RAILS that test steelmakers For many years Inland has been lead- The same degree skill evidenced the making bumper bars practiced throughout the Inland Bar Department. When you buy hot rolled bars from Inland, you secure product that will meet the specifications required speed your production and reduce your shop costs. When you seek high quality bar stock, come Inland. TRACK ACCESSORIES REINFORCING BARS 3 as IT oO | : undisputable preference metallurgists for the pyramid principle hardness testing has generally been justified oretical relationship with ideal hardness scale linear magnitude. Besides, only one scale covers the en- tire hardness range the softest the hardest technical material (see Fig. 1). the other hand, the simplicity using the universally known Rockwell testing apparatus, together with the independence the factor upon the obtained results, has placed the Rockwell, beyond doubt, testing machines. This simple factor well the unreasonably high cost most the diamond pyramid test- ing machines retarded their anticipated adoption America’s industries almost exclusively laboratory sphere interest. justice the pyramid hardness testers, must recognized that the impression ranges the Rockwell ma- chine are definite shortcomings the Rockwell method. This does not en- able operators engineers com- prehend the actual relative hardness many materials without reference WEL HRUSKA Metallurgical Engineer, Electro- Motive Corp., Grange, ° author herein reports data the quite unethi- cal procedure combining the definitely advantageous Rockwell principle speedier measurement depth im- pression hardness testing together with the more logi- cal and metallurgically ac- curate application the 136 deg. diamond pyramid indentor. Tests metals, from soft copper hard tool steel, indicate that the accuracy depth mea- the Rockwell machine lend themselves very accurately determining D.P.H. hardness. Conver- sions hardness numerals are, how- elaborate conversion tables. ever, nearly always sources con- siderable controversies and suspicions, even the tests refer the same principle identical apparatus. initial step toward some sort simplification the many confus- ° ing hardness scales today, the writer has conducted series tests using 136 deg. diamond pyramid the newest type Rockwell hardness tester. This admittedly somewhat unethical procedure was intended combine the definitely advantageous Rockwell principle speedier measurement depth impression together with the more logical and metallurgically accu- rate application the 136 deg. dia- mond pyramid indentor. The tempta- tion was also too obvious cover the technically important range from de- cidedly soft metals such copper and aluminum the hardest tool and alloys. The Rockwell testing machine used the present research work was new apparatus in. capacity, equipped with thoroughly calibrated 120 deg. diamond cone. The compara- tive 136 deg. diamond dentor was designed permit the full use the standard chuck the Rockwell machine. The complete assembly the apparatus shown Fig. Particular care has been exer- cised duplicating the principles set forth primarily the originators the pyramid hardness test. Thus, the loads the machine were first cali- brated 60, 100, and 150 kg. THE IRON AGE, February 1940—29 ey, \ \ pus : . ° ° ° BRINELL (B), (S) HARDNESS utilizing standardized proving ring. The apparatus used well its ar- rangement shown Figs. and order verify the reliability the 136 deg. pyramid the light recent work Fuller (see Transactions A.S.M., Dec. 1937, pp. 1198-1206), measurements the squareness the resultant impressions were made with 60, 100, and 150 kg. load alloy steel block Rock- well C-63.5 hardness. Fig. trates the observed variations ap- pearance. The reported readings were further checked means standard metal- lurgical microscope newest design 100 magnifications. The ocular the measuring microscope exact duplicate the standard Vickers eye- piece, but domestic make. The Rockwell apparatus was, all tests made, set that the duration actual loading conformed minimum time required conduct standard diamond pyramid tests. mentioned above, special care was taken approach pre- cision the Rockwell instrument that the highest type precision instruments available from domestic and foreign sources carry out hard- ness tests with 136 deg. diamond pyra- Any attempt use the Rockwell machine for pyramid must theoretically correct and es- sentially duplicable. Analysis the factors entering into the functional performance each testing machine makes clear that the Rockwell scale proportional only measured depth impression, whereas, the pyramid 30—THE IRON AGE, February 1940 400 500 600 (D) ABOVE IG. pyra- mid principle hardness testing has the only linear scale which covers the en- tire range the softest the hard- est technical ma- terial. RIGHT 2—This Rock- well hardness tester equipped with D.P.H. in- dentor. 700 hardness conventionally function the length the diagonal regard square impression. Both are, course, equally dependent upon the load and somewhat upon the time their application. The numeral (D.P.H.) is, therefore, the quotient load over the area the impression the 136 deg. pyramid. The load always stated kilograms when testing hardness either the Rockwell D.P.H. method. However, dimensional characteristics are ascer- the Rockwell method, but they are re- ferred millimeters all pyramid hardness testing. differences mind, becomes neces- sary express the depth penetra- tion units. standard Rockwell equip- ment indicates thus only Rockwell units, but the pyramid hardness may equally well calculated length the diagonal, shown Fig. Bearing these two consideration simple geo- 400 | | | | | 100 | in metrical displacement, apparent that the depth indentation the 136 deg. square based pyramid one- seventh the diagonal the impres- sion. This decrease sensitivity the D.P.H. test Rockwell machine necessitates more accurate reading the indicator values the dial the apparatus, but naturally offset the possibility check also the diagonal means suitable micro- meter microscope. The latter dimen- sion, the length the diagonal, the customary index the D.P.H. numeral and ordinarily compiled tabular form. Such tables accompany- LEFT tion the Rock- well hardness tester. CENTER and Rockwell brale (right) in- dentors. BELOW IG. Photomi- crographs (at 100 diameters) D.P.H. indentations test blocks Rockwell C-63.5 and 100 kg. (right) loads. ° ° ° 4 ing each hardness testing device are, standardized somewhat different than those available with Rockwell machine. With this determine numerals without much delay. practical experience with this he mwever, le mics operator method was found that the kg. and perhaps the 100 kg. loads are the suitable for general investigations the probably most ones load having slight advantage for thinner materials tested. the original research experiments the materials given Table were selected. The pieces measured in. The surfaces were ground and polished increase the accuracy all made each test block and averages tests were used the computations referred the subsequent paragraphs. at- tempt was made check the chemical compositions the specimens against those furnished the suppliers, be- cause interest was exclusively the performance the diamond indentors rather than study material characteristics. Almost needless say, the corre- lating Rockwell tests were made under standard conditions with new dia- mond. making these was realized that the scale based primarily measurement depth conditions. order theoret- ically calculate these minute depths, customary subtract the dial read- ing from 100 and multiply the re- sultant dial units divisions con- stant 0.00008 in. which equal about 0.002 mm. tests made calculating these depths indicated that there slight deviation from the hypothetical figures. THE IRON AGE, February tions are obviously based determi- impression made standard Rock- Diamond Pyramid Hardness Numbers (For Kg. Load) The foregoing remarks Diagonal, Hardness Diagonal, Hardness Diagonal, Diagonal, Hardness characteristics type 0.312 1140 0.392 724 299 1.01 109 lating the depth impression 0.314 1126 0.394 717 0.62 289 1.02 107 from the actual readings the Rock- 0.316 0.396 709 0.63 280 1.03 105 well dial against those determined 0.318 1100 0.398 702 0.64 dividing the 0.320 1086 mined diagonal seven. The diagram 0.322 1073 0.405 678 Fig. shows this This ap- 0.326 1046 0.415 0.68 95.4 parent discrepancy the test may 0.328 1034 0.420 630 0.69 234 1.09 93.6 have some explanation the quite re- 0.330 0.425 616 0.70 227 1.10 92.0 cently evaluated elastic recovery the standardized Rockwell test. That 1009 0.430 602 0.71 90.3 997 0.435 588 0.72 215 1.12 88.7 this finding has comparatively little 0.336 985 0.440 574 0.73 209 1.13 87.1 bearing the accuracy D.P.H. 0.338 974 0.445 0.74 203 1.14 85.6 tests with Rockwell machine shall 0.340 962 0.450 0.75 shown later. The paper Howard 0.342 0.455 536 0.76 193 Scott and Gray “Relation 513 0.78 183 1.18 79.9 502 0.79 178 1.19 78.6 Pyramid Hardness Scales,” presented 0.350 908 0.475 492 0.80 174 1.20 June, 1939, before the American 0.352 898 0.480 482 0.81 170 1.21 76.0 Society for Metals, would certainly 0.354 888 0.485 472 0.82 166 1.22 74.8 confirm this contention. 0.356 878 0.490 462 0.83 162 1.23 73.5 0.358 868 0.495 453 0.84 158 1.24 72.3 Resul esults Tests 0.360 858 444 0.85 154 1.25 71.2 0.362 849 0.505 436 0.86 150 1.26 70.1 careful scrutiny the mentioned 0.364 840 0.510 428 0.87 147 1.27 69.0 papers published this year the light 0.366 83! 0.515 420 0.88 144 1.28 67.9 work performed during the course 0.368 822 0.520 412 0.89 140 1.29 66.9 that this application the 0.374 795 0.535 389 0.92 131 1.32 63.9 Nas 0.376 787 0.540 382 0.93 129 1.33 62.9 tageous the metallurgical investiga- 0.378 778 0.545 376 0.94 126 1.34 61.9 tor. summarizing the tests made 370 1.35 61.0 with soft and very hard materials and 0.382 762 0.56 356 0.96 121 1.36 presenting these results 0.388 739 0.59 319 0.99 114 1.39 amazed the comparative accuracy 0.390 732 0.60 309 1.00 1.40 56.8 the tests. The mentioned test block, which represented materials com- mercial grades, with their inherent and expected variations, indicated, never- diagonal 1/100 mm. theless, that the general magnitude the tests uniform whether 60, 100, 150 kg. load applied upon the TABLE pyramid Test D.P.H. Numeral (at kg.) tween the Rockwell hardness and Block Type Metal Dial Read- Diagonal, Rockwell the dial readings during the No. ing D.P.N. Hardness test have very clear This Aluminum 46.5 1.485 0.212 50.5 further borne out comparing the Weld 59.0 0.875 0.125 145 various materials. Microscopic mea- S.A.E. 1020 steel 59.8 0.880 0.126 144 surements all Rockwell well Mn-Mo plate 64.0 0.735 0.105 206 1.7 indentations check with the ex- Stainless 18-8 66.9 0.725 0.103 203 2.6 pected uniform trend very nicely. The Pearl. 68.6 0.705 224 12.1 hardness numerals, determined undet Pearl. plate 70.8 0.690 0.098 234 18.2 150 kg. load with standard brale, S.A.E. 6145 steel 76.4 0.580 0.083 330 35.7 versus D.P.H. numerals determined 6145 81.6 0.497 449 50.6 with the same machine but means High Speed steel 86.9 0.355 0.051 883 66.7 the square based pyramid, indicate 32—THE IRON AGE, February 1940 At | parison the graphical relationship shows that they are amazingly close the most recent conversion tables hardness Scott and Gray, and are also within experimental error the conversion tables published manutacturer the Rockwell testing machine. The somewhat description results obtained this investiga- LEFT IG. 6—The pyra- mid hardness may calculated from e the length the z ”) a RIGHT between depth D.P.H. impression and Rockwell dial reading. tion seems indicate that the accu- racy depth measurements the Rockwell machine lends itself de- termining hardness. would, therefore, perhaps very remuner- ative experiment design gage which would read numerals without reference many scales the present Rockwell machine has offer. addition would eliminate the use steel balls admittedly variable hardness char- DIAL READING ROCKWELL TESTER acteristics and variable sizes without the unavoidable inaccuracy the test. Whether not the same would true for superficial Rockwell machines would naturally have proved experiment. Nevertheless, the fore- going experiences are offered mainly for those who are interested making hardness measurements with- out the necessary expense having just another hardness testing machine their laboratories. DIAL ROCKWELL UNITS RIGHT IS. 9—Graphic between the Rock- BELOW ROCKWELL NUMBERS -40 +20 +40 +60 ROCKWELL "C" HARDNESS ROCKWELL DIAL READINGS WITH THE IRON AGE, February Se -60 -40 -20 +20 +40 +60 progress has been achieved during the past decade equipment used for the hot and cold working steel and other metals. During the same period similarly important, although less spectacular, de- velopment has taken place academic knowledge the basic principles underlying the flow metals the forming operations. However, the com- mercial processes offer considerable resistance any attempt developing theoretical foundation due the interference numerous factors. Thus, any mechanical treatment the plastic flow must allow for the effect these numerous factors, but must the same time simple enough not extend the unavoidable calculations specific case beyond the limits practical usefulness. This paper presents such attempt abstract and correlate the present knowledge the plastic flow metal—the paper was originally presented the recent symposium the Cold Working Metals sponsored the Metallurgy Department the Carnegie Institute Technology. complicated relations which control the plastic flow met- possible calculate the stress and the strain produced the different work- ing processes from few known fun- damental facts and some assumptions. the present time these processes mit the formation general theory which will predict all details, least not without enormous amount calculations. However, possible follow the utilizing some simple laws and some formulas derived from these laws. The work expended any deform- ation process consumed for two dif- ferent functions, overcome internal friction the resistance” the metal and overcome the external friction. The flow resistance the metal de- Sachs, Ver. deut. Ing., Vol. (1928), pp. 734-736. Ros and Versuche Zur Klaerung der Frage der Bruchgefahr, Zurich, 1926 and 1928. Herrmann and Sachs, Metall- wirtschaft, Vol. (1934), pp. 687-692, 705-710. 34—THE IRON AGE, February 1940 pends several factors which will discussed detail. The most impor- tant these factors are: (1) The general state stress. (2) The strain-hardening. (3) The rate deformation. (4) The temperature. The general stress conditions uniformly stressed metallic body are determined three principal stresses, and cube can cut from the body such manner that only these principal normal its surfaces, and shear stress, and the intermediate principal stress. generally positive tension stress pression stress. However, the flow metals can expressed simpler way, using value which corresponds the maxi- mum shear stress occurring ma- terial This (or the maximum shear stress tmax.) has been found approximately constant num- her different deformation processes, assuming that the metal definite the case pure tension, there only one principal stress pression, there also only one prin- cipal stress s,) present but neg- when one these types words, the stress required deform test bar tension compression can taken the basic value for any deformation process. Unfortunately, gives only approximate value, and under stress conditions, the flow stress has been tions may occur rolling, panding tube internal and partially deep drawing.” The practical significance the shear stress law for this latter process illustrated Fig. which repre- sents the strength the metal during deep drawing under tions. The breaking strength thin-walled cup drawn with wel! rounded-off punch may more than per cent higher than strength the metal, while the lateral pressure punch with sharp radius may cause heavy walled cup tear the bottom from corresponding less than per cent the tensile strength. However, this deviation minor practical impor- tance and the maximum shear theory with constant flow stress ciently accurate for most commercial considerations. generalization can derived from the same assump- tions. The introduction the re- does not alter the flow stress: This law can extended further, | 4 | a | i | ° ° hydrostatic pressure does not change the state strain either. Thus the three processes stretching (in ten- sion), drawing and extruding compression and two axial tension such would occur the bottom drawn shell: are similarly related and distinguished hydrostatic tension The flow stress actually increases slightly with increasing pressure, bu! this can disregarded for most prac tical purposes. The strain body also deseribed principal de- GEORGE SACHS Case School Applied Science lfa sphere cut from the body and deformed ellipsoid, the three deformations the directions the three axes the tions. Again the largest strain and always positive, the smallest and always negative strain. extension bar having length the length the case the compression bar having original height the height h,: The directions the principal de- formations are always parallel the directions the principal The amount the strain different determined the stresses according The strains may calculated the stresses are known throughout form- ing process. This has been done for the deep drawing (without ABOVE IG. |—Principal stresses, and moximum shear stress, trength Tensile deep- drawing ¢ Ratio 024 in. 0.40 in. 0.7 0.02 0.06 0.08 Sheet thickness, in. 2—Strength shells during deep drawing, depending upon the metal thickness and the shape (radius) the punch. For 67/33 brass. Blank diameter 2.40 punch diameter in. THE IRON AGE, February 1940—35 ; 1.2 | = Increase thickness, per cent Increase thickness, per cent Ratio Original diameter fibre Blank diameter 3—Strain (increase thickness) blank (aluminum) during deep draw- ing. Reduction per cent. Calculated (left) and measured (right). a) True Ib. per sq. in. Reduction area tension, per cent Reduction height compression, percent copper tension and compression. shell having diameter twice that the punch, Fig. The cal- culated changes thickness dif- ferent locations during the transfor- mation the blank the cup closely correspond the measured ones, showing per cent increase thickness the upper edge and slight reduction thickness the bottom the shell. stresses created the punch pressure cause additional stretching the and the fillet the cup. the consideration strain Sachs, Spanlose Formung, Berlin, 1930, pp. 33-37. 5P. Ludwik, Elemente der Technologi- schen Mechanik, Berlin, 1909. Sachs, Spanlose Formung, Berlin, 1930. E. Siebel, Steel, Vol. 93 (1933), Nos. 26; Vol. (1934), Nos. 19. Ludwik, Elemente der Technologi- schen Mechanik, Berlin, 1909. Ludwik and Scheu, Stahl Eisen, Vol. (1925), pp. 373-381. 7G. Sachs, Spanlose 1930, pp. 43, 66. Unckel, Journal Institute Metals (London), Vol. pp. 171-196. Berlin, 36—THE IRON AGE, February 1940 deformations, value called the fective «= +e) assistance: During plastic deformation the vol- ume metal only slightly altered, perhaps 0.1 0.01 per cent, and can considered physical constant. This gives the following equations: Vs = V; = V.(1 +e,)(1 +e)(1 + e;) where: volume before deformation volume after deformation This equation translated the log- arithmic functions results: or: tate = (0) According this formula least one the three deformations posi- tive, another negative, and the third The single may tion which equal the sum the other two but different sign called the maximum strain Its numerical value any case the half sum the absolute values the individual deformations RESISTANCE FLOW AND The degree strain- hardening metal produced dif- ferent cold deformation processes (at given temperature) determined primarily the amount deforma- tion, while the etfect the speed deformation negligible, far The degree strain-hardening fected different processes gov- erned The main factor the amount the previously Reduction per pass: (lubricated) Reduction rolling, per cent IG. 5—Tensile strength rolled steels and copper for different re- ductions (Siebel). Flow strength),1000 per sq. IS. Strain- hardening curves for different metals. Strain (reduction thickness), per cent -20 =) 4 40% Stainless H Ww w a a 45 Total reduction area drawing and cent IG. 7—Stress-strain diagrams for steel wires, drawn from the an- nealed condition different reduc- tions and with dies various shapes. disre- garding the sign. Therefore, for ten- sion and compression, the degree strain-hardening will the same for the same amount strain”: more convenient form compare the two values: discussed or: hy h, hy compression lo and tension can replaced the volume remains constant: l h, h, f., other words, the degree strain- hardening tension tor reduction area (in per cent) identical with the amount hardening compression that ef- fected the same reduction height thickness (in per cent). Fig. shows the results some experiments with copper, which were initiated verify this relation. The equivalent deformations for several working processes this basis are: Rolling: Reduction area, and sheet and strip rolling. Drawing: Reduction area. Reduction area. Piercing: Reduction wall thick ness. forming where the strain varies the differ- ent sections, the quantity and distribu- tion the strain has determined special investigations. cesses, Strain-hardening curves can de- Draws reduction) | copper wires with various oxygen contents drawing with different dies (Remmers). termined tension and compression tests the point where these tests unreliable because the fects necking and friction, respec- tively. The stresses should related the actual cross-section and not the conventional which refer initial cross-section. The further extension the curves can obtained from tensile stresses strength rolled metal, Fig. which approxi- mately correspond the for hard tempers. shows number curves for different metals. most commercial operations, and wire particular, the de- gree strain-hardening generally higher than that derived foregoing considerations. This at- tributable non-uniform flow the metal, which causes increased amount deformation and therefore strain-hardening, com- pared with ideal homogeneous de- formation, such tension. shown Fig. this additional strain- hardening varies considerably with the specific drawing conditions, very small for wire reduced heavy draw low-friction tungsten carbide die having acute angle. The flow metal during wire draw- ing, however, becomes very irregular with increasing die angle, with high friction die material, such steel, and with small reductions. This has been demonstrated both X-ray investigations and residual stress determinations. Also, the less uniform the flow the metal, the greater the tendency form defects any type. Thus, according Fig. cop- per wire with certain oxygen content may subjected higher total reduc- tions with acute angle than with wide angle very non-uniform flow metal has been observed extrusion, which can also considered drawing process with wide open die. These relations are illustrated schematically Fig. other working processes, such rolling (see Fig. 5), and tube rawing representation the strain different forming proc- esses, resulting the same external change shape. drawing, the flow metal compara- tively uniform, while the other hand, such processes die forging permit detailed analysis complete data the state strain are desired. Ed. Note: Next week the author will conclude this report with data the path course deformation the dif- ferent working processes, and the effect friction and lubrication. THE IRON AGE, February 1940—37 40 0.04% 2 t -Fe 4 + if 8%| 4 0.16 Hie Geuarees — Stretching This results the simple relation: HESE data are from paper presented the recent 20th annual meeting the American Welding So- ciety. The complete paper includes description certain the more recent applications the flame-hardening process special shapes requiring unusual control contour esses—flame hardening, flame softening and flame strengthen- ing—flame strengthening the newest and least known. is, however, self- practically identical with hardening treatment. The purpose flame strengthening differs appreciably, however, that the intent strengthen highly-stressed parts locally the regions excessive concentra- tion stress. example such stress concentration, determined photoelastically, shown Fig. The process directed particularly parts which are subjected repeated stresses and which are thus “Photoelastic Studies Stress Fnainecering, 58. 485 (1936). 38—THE IRON AGE, February 1940 ZIMMERMAN Development Engineer, Linde Air Products Co., New York the hardened zone and special materials which the process has been applied only recently with success. The general subject flame softening was also discussed, with particular reference the important part played the oxy-acetylene cutting the hardenable steels. tecting against fatigue again—to borrow the slogan well known paint manufacturer—a case “save the surface and you save all.” other words, while the treatment may appear identical with flame tions part which will never subjected wear, for the pur- pose increasing mechanical strength resistance against the formation and propagation fatigue cracks. virtue the extreme flexibility the process, the use ing makes possible effect savings comparison with the complete heat treatments where, many instances, 100 per cent part would fully hardened and drawn order in- crease the strength the per cent which may subjected the maxi- mum stresses. previously stated, there tically difference between the strengthening procedure and flame hardening. order produce the desired contours into the base metal regions lower stress, and thus prevent sharp discon tinuities, has been found desirable employ special heating heads where the complexity the part lend itself readily the use simple standard equipment. The cooling the ening process may less drastic than the case flame hard ening. Whereas generally agreed that high hardness indicative the maximum fatigue endurance properties. Somewhat lower than maximum hardnesses shown advantageous with regard resistance repeated stresses. This probably caused the need for certain amount ductility provide for minute plastic regions high stress The need for tempering, even though low temperature, even more vious the case flame strengthen- ing than the case flame harden- Strengthened Parts Tested While specific information con cerning the performance | | \ ° ( 4 ° ° ° \ \ = ( strengthened parts yet available, the results laboratory tests are interest. Fig. shown part sectioned and etched fatigue specimen the type employed series tests determine the advantages the flame-strengthening process. this specimen sharp shoulder was intentionally introduced the mid-section the test specimen which submitted uniform bending during rotation. well known, and has been previously indicated the photoelastic illustration Fig. this abrupt change section stress raiser appreciable magnitude. was thought that flame strength- ening could divert the fatigue failure from the sharp cornered fillet the shank uniform diameter, the treat ment, effect, would have completely eliminated the weakening effect the stress raiser. This has been found the case, shown Fig. which tured specimen showing the break the center. investigate further the effect flame strengthening, the entire reduced section surface, well the fillets, was strengthened second series specimens. these tests was soon found possible throw the fa- tigue failures the untreated metal the sections large diameter. Actual dimensions the specimens under test were 7/16 in. and in. for the small and large diameters respectively. This variation diameter corresponds much greater difference the induced stress under load, the ratio stresses for uniform bending moment being almost 1.5:1. Future Possibilities Results one series comparative fatigue tests are shown Fig. The endurance limits for four sets specimens the same type but different treatment are shown. The base material this series tests was S.A.E. 1045 steel. attempt was made determine the actual en- durance limit the material, which probably the neighborhood ° ° IG. Photoelastic study showing stress concentration shal- low grooves pure bending. ° ° 45,000 Ib. per sq. in. Instead, the cal- culated stresses for the test specimens were based the small diameter with- out regard the stress raising factor corresponding the sharp cornered shoulder. the lower curve will seen that the nominal endurance limit indicated approximately 26,000 lb. per sq. in. This series specimens was oil-quenched from 1540 deg. and drawn 400 deg. The next curve showing nominal endurance limit 32,000 per sq. in. corresponds the series spect- mens treated indicated Fig. namely, untreated base metal with esting note that sparse heat treatment has developed improved fatigue resistance com- pared with fully quenched and drawn specimen, although must admitted that the fully hardened would probably have shown improved results had they been water-quenched. The upper curve, indicating nom- 2—Macro-etch failed fatigue test specimen showing flame strengthening the regions stress concentration the test specimen, untreated, was the neighborhood 18,000 Ib. per sq. in. assumed that the test material itself has endurance limit 45,000 per sq. in., the actual stress raising factor indicated 2.5. value which not inconsistent with published data.* the second curve from the bot- tom, the nominal endurance limit 3—Graphical representation test results, showing determina- tion endurance limits. inal fatigue limit around 52,000 Ib. per sq. in. was obtained testing series specimens which had been flame strengthened not only the fillets but across the entire reduced section. The improvement obvious. The results these and other labo- ratory tests progress indicate that there may considerable future for the flame-strengthening process. strengthened fillets only Flame strengthened fillets and entire reduced section Specimen removed unbroken 100,000 1,000,000 Stress cycles 10,000,000 THE IRON AGE, February 1940—39 “it * ~ as 70,000 50,000 O = 10,000 following analyses cast iron are included typical ex- amples some the copper alloy cast irons now being used. These analyses not begin cover all the variations which can utilized with economy but merely serve illustrate the way which the unusual charac- teristics copper cast iron can Per Cent Total carbon 8.40 Silicon section uniform- ity and machineability together with improved wear resistance. Tensile strength—-30,000 36,000 Ib. per sq. in. Total carbon 3.60 Manganese 1.00 1.25 etc. Reason—Closes the grain without tendency toward cracks loss machineability. Tensile 38,000 Ib. per sq. in. Carroll and Metal Prog- ress, 1936. 40—THE IRON AGE, February 1940 3.20 to 3.40 Use—Gears, etc. Reason——Density, wear resistance, and machineability, together with improved finish. Tensile strength—34,000 40,000 Ib. per sq. in. Total carbon 3.10 3.30 Use—Heavy machinery, etc. density combined with good machineability and im- proved wear due the copper fre- quently factor this case also. Tensile 45,000 Ib. per sq. in. The first analysis given that the Ford cylinder block and typical that used for cylinder blocks many other manufacturers. case 0.75 per cent copper sufficient insure the section uniformity and machineability that desired these castings. pointed out the quota- tion (last week) from the paper McCarroll and McCloud! the Ford Motor Co., this iron also has better wear resistance than that found the unalloyed irons, but the effect cop- TOM BARLOW Engineer, Copper Iron and Steel Development Association, Cleveland per uniformity throughout the vari- ous sections the prime consideration. The second analysis given typical castings such flywheels where unusual density required cast- ing having rather drastic changes section size. should noted this iron that the carbon and manganese are relatively high combined with the fairly low silicon and 0.75 per cent copper maintain machineability. pointed out the paper McCarroll and the same density could obtained these castings the use lower silicon content and copper, but this case the casting would difficult machine well heavy sections and cracks the lighter sections. The third analysis given typical such applications gears which good machineability desired but somewhat greater density and wear re- sistance are necessary. These castings usually have definite changes sec- tion size and are therefore liable cracking and porosity unless some al- loy such copper used maintain the structural uniformity. The fourth analysis given adapted heavy castings which the ability copper higher percentages | } } enhance density combined with good machineability prime importance. Unlike most other graphitizers, copper has very definite tendency close the grain large castings, particular- the higher percentages. The use this amount copper normally the physical properties. When higher strength, together with good toughness, low chill, extreme density, and good machineability are desired, the use copper combina- tion with some other element fre- quently the most economical method obtaining the desired results. number such combinations have been investigated and are now being used commercially amounts. One the most common these alloy combinations that copper and chromium, which two examples are follows: Per Cent Total carbon 3.10 3.50 compressors, etc. Reason—Density, resistance pres- sure together with machineability and improved strength. per sq. in. Il Use—Brake drums, hoist drums, etc. wear resistance, stability, and density. Tensile strength—35,000 45,000 Ib. per sq. in. portant alloy addition the gray iron foundry. De- tailed data typical copper alloy irons and their physical properties and applications are presented herein, well data special irons and information general foun- dry practice. the first sec- tion this two-part article, last week, the author de- scribed the function cop- per chill reducer and controller, pearlite stabil- izer, strengthener and hard- ener. affected, copper and chromium should added cast iron proportions chromium alone strengthen and hard- cast iron materially, but render progressively more brittle and difficult machine. If, however, they are ac- companied balanced addition copper, the strength increases the same greater extent but since the formation free carbide prevented, the iron remains tough and machine- able. When such combination chromium and copper added ferritic base iron, the resulting iron tends pearlitic because the cop- per does not accelerate the breakdown pearlite but merely prevents the formation carbide due the addi- tion chromium. this same com- bination, however, added base iron already containing free carbide hard spots, extra copper would necessary break down the original carbide formation addition that required compensate for the car- bide formed the the most economical increases ten- sile strength and other physical prop- erties, copper-chromium combinations and other alloy combinations should base iron whenever possible. Among the many applications copper-chro- mium irons are brake drums, machine tool castings, valves, and pump cast- ings. One specialized application heat resistant castings such fur- nace parts. The first copper-chromium analysis shown frequently used such parts pumps and compressors. con- tains approximately balanced ratio copper and chromium. This com- bination permits higher physical prop- erties than would obtained from the unalloyed irons, together with greater density, resistance pressure, and equal machineability. pump cast- ing the use this same composition importance due increased corro- sion resistance. The second analysis shown which typical small brake drums, hoist drums, and sheaves, contains some- what higher percentage both copper and chromium promote greater ther- mal stability and somewhat higher physical properties than could ob- tained from the first analysis. Copper molybdenum combinations have received favorable comment from 3.10 per cent total carbon, per cent silicon cast iron machine rail containing per cent copper primarily for the purpose increasing the tensile strength, machineability, and castability. This casting weighs approximately 1200 and showed tensile strength 48,000 50,000 sections varying from in. in. Photo courtesy Bowler Foundry Co., Cleveland. THE IRON AGE, February 2 | } | many users. One application which calls for nearly 10,000 tons per year copper-molybdenum cast iron one foundry alone that large truck brake drums. This same type iron also used extensively for crawler crane drums, hoist drums, spill gate valves for corrosive waters, and other applications where high strength, wear resistance, toughness, and even corrosion and heat resistance are re- quired. Per Cent 3.20 3.30 Molybdenum .......... 0.40 0.60 Use—Brake drums, hoist drums, ete. Reason—Excellent wear resistance, thermal stability, strength, and machineability. 50,000 Ib. per sq. in. Molybdenum .......... 0.50 1.10 Use—Diesel cylinders, heavy truck blocks, etc. strength, sistance, density, combined with good machineability and finish. Tensile strength—50,000 80,000 per sq. in. the chill depth remain con- stant, copper and molybdenum should added the cast iron approxi- mately equal proportions, the exact ratio depending somewhat the car- bon content. However, molybdenum combinations, the copper acts increase the strength and for economy’s sake usually added more than equal proportions. Unlike the copper-chromium combination, copper tends increase the Brinell when added excess per cent. This combination permits very high strength, toughness, hardness, and wear resistance combined with good One the strongest cast iron com- binations commercial use today that shown the second copper-mo- lybdenum analysis. This cast iron used for very heavy Diesel cylinder blocks and similar applications where extreme strength combined with very good wear resistance, density, and sat- isfactory machineability are prime importance. This combination al- loys used commercially castings showing tensile strengths 80,- 000 Ib. per sq. in. with machineable Brinell hardness below 300. Another alloying combination which 42—THE IRON AGE, February 1940 carbon per cent silicon cast iron steam cylinder containing per cent copper for the purpose increasing tensile and transverse strengths, density, machineability, and corrosion resistance. The casting weighed approximately 1800 and showed tensile strength 45,000 per sq. in. 34-in. section. Photo courtesy Bowler Foundry Co., Cleveland. rapidly coming the front that vanadium and copper, which Per Cent Total carbon .......... 3.10 Use—Brake drums, metal molds. stator blocks, liners, etc. strength, section uni- formity, and unusual response heat treat- ment. Tensile strength—45,000 60,000 lb. per sq. in. any given hardness, combina- tion per cent copper with 0.15 0.20 per cent vanadium gives in- crease from 5000 15,000 Ib. per sq. in. more than straight vanadium iron. other words, higher strengths are obtained with the same Brinell hardness with copper-vanadium iron than with either straight copper straight vanadium. These irons have excellent properties respect chill, microstructure, and physical proper- ties. They have been used for brake drums, and are beginning used for molds receive hot metal. The copper-vanadium combination has two important characteristics. The first these the ability this combina- tion respond heat treatment. Such castings stator housings, which must withstand excessive wear and should therefore have very high Brinell hardness but which must machined, can readily cast with this combination alloys machineable Brinell hardness and then readily heat treated quench-draw treatment the desired structure. Another char- acteristic the copper vanadium com- bination the unusual uniformity structure and properties castings various sections and castings from dif- ferent heats. This combination fre- quently recommended where the ability reproduce the same properties from day day important and where uniformity section structure re- quired. Another alloy combination that has received considerable attention re- cent years that copper and nickel. Data obtained both experimental foundries and commercial foundries indicate that copper and nickel are very similar their effect Brinell hardness, tensile strength, and other physical properties cast iron. How- ever, there are certain essential differ- ences between these alloys which fre- quently make the combination the two desirable. The following analysis typical nickel-copper cast iron ' I | ( | | & | well known commercial practice the present time: Per Cent Total carbon 3.60 Silicon 1.80 2.00 Copper Use—-General machinery. Reason —- Increased density, uni- formity, and improved surface. Tensile strength—30,000 38,000 per sq. in. The solubility copper cast iron limited but can increased the addition nickel. For example, the absence other alloys, the amount copper that can satisfactorily dis- solved cast iron ranges from 2.5 per cent, depending somewhat the composition and somewhat the sec- tion size and cooling rate the cast- ing involved. However, when large amounts nickel are added, the solu- bility copper cast iron can increased much per cent. Therefore, applications requiring large amounts alloying element such copper nickel, combina- tion half nickel, half copper, the higher percentages, two-thirds nickel, one-third copper, utilized insure good distribution the alloy and complete solution the copper. For this same reason, combinations nickel-molybdenum, copper-nickel va- nadium, etc., are frequently used the highly alloyed cast irons. Special Copper Cast Copper frequently used cast iron for special purposes, particularly heat and corrosion resistance. One the better known corrosion resistant materials containing from per cent nickel with from per cent copper unusually resistant such ARGE check valve body containing from 0.5 per cent copper for the purpose increas- ing corrosion resistance, and improving the finish. Photo courtesy Meehanite Metal Corp. corrosive mediums brine, sea water, ordinary atmospheres, and many chem- icals. Due its unusual toughness and heat resistance, also finds many applications for such purposes cyl- inder liners, sleeves, and grates. Cop- per used this particular alloy combination largely for the purpose decreasing the cost and increasing the corrosion resistance some media. Another fairly well known corro- sion resistance application that copper cast iron pipe containing from 0.75 1.50 per cent copper, which used particularly condenser coils for oil refineries, mine water applica- tions, and for acid resistance. Corro- sion resistant properties copper cast iron are also taken advantage large spill gate valves and similar cast- ings used highly corrosive waters, such would encountered the Monongahela River. These castings frequently utilize copper-molybdenum combinations take advantage the additional strength and density im- parted molybdenum. Copper finding increasing use heat resistance applications, particu- larly combination with chromium. these applications copper effec- tive reducing scale formations high temperatures and counteracting the embrittling effect the chromium. typical cast iron this class would contain approximately per cent cop- per and per cent chromium. new complex alloy cast iron utiliz- ing the effect copper the trans- formation rates that containing per cent copper, per cent man- ganese, and 0.5 per cent molyb- denum. This material has as-cast h