^__C~~ ~^~~ ~ENGINEERING RESEARCH INSTITUTE UNIVERSITY OF MICHIGAN l M l ^Gd 2 ANN ARBOR REPORT NO. 2 MECHANICAL PROPERTIES OF MACHINABILITY PROGRAM WORK MATERIALS By L. V. COLWELL W. C. TRUCKENMILLER Project M993 U. S. ARMY, ORDNANCE CORPS CONTRACT NO. DA-20-O18-ORD-11918 December, 1952

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SUMMARY SHEET I. Engineering Research Institute, University of Michigan, Ann Arbor, Michigan. II. U. S. Army, Ordnance Corps. III. Project No. TB4-15 Contract DA-20-018 ORD-11918, RAD No. ORDTB-1-12045. IV. Report No. WAL 401/109-2. V. Priority No. VI. Investigation of machinability of titanium-base alloys. VII. Object: The object is to investigate the machinability of commercially pure titanium and three alloys of titanium. VIII. Summary: Tensile tests and Brinell Hardness tests were made on five of the six machinability work materials. Tensile test data are plotted as stress versus natural strain. Hardness tests over a range of loads provides Meyer exponents. The materials tested were SAE 1045 hot-rolled steel, type 304 stainless steel, and titanium grades Ti 75A, RC 130B, and Ti 150A. ii

TECHNICAL REPORT DISTRIBUTION LIST Copy No, Contractor 1 Department of the Army Office, Chief of Ordnance The Pentagon Washington 25, D. C. Attn: ORDTB - Res. and Matls. 2-3 Same. Attn: ORDTA - Ammunition Div. 4 Same. Attn: ORDTR - Artillery Div. 5 Same. Attn: ORDTS - SmAll Arms Div. 6 Same. Attn: ORDTT - Tank Automotive 7 Same. Attn: ORDTU - Rocket Div. 8 Same. Attn: ORDTX-AR - Executive Library 9-10 Same. Attn: ORDIX 11-12 Commanding General Aberdeen Proving Ground Aberdeen, Maryland Attn: ORDTE R. D. and E. Library 13 Commanding General Detroit Arsenal Center Line, Michigan 14-15' Commanding Officer Frankford Arsenal Bridesburg Station Philadelphia 37, Pa. 16 Commanding Officer Picatinny Arsenal Dover, New Jersey 17-18 Commanding Officer Redstone Arsenal Huntsville, Alabama 19 Commanding Officer Rock Island Arsenal Rock Island, Illinois iii

Copy No. Contractor 20 Commanding Officer Springfield Armory Springfield, Mass. 21 Commanding Officer Watervliet Arsenal Watervliet, New York 22-23 Central Air Documents Office U. B. Building Dayton 2, Ohio Attn: CADO-D 24-25 Commanding Officer Box CM, Duke Station Durham, North Carolina 26 Chief Bureau of Aeronautics Navy Department Washington 25, D. C. 27 Chief Bureau of Ordnance Navy Department Washington 25, D. C. 28 Chief Bureau of Ships Navy Department Washington 25, D. C. 29 Chief Naval Experimental Station Navy Department Annapolis, Maryland 30 Commanding Officer Naval Proving Ground Dahlgren, Virginia Attn: A. and P. Lab. 31 Director Naval Research Laboratory Anacostia Station Washington, D. C. iv

Copy No. Contractor 32 Chief Office of Naval Research Navy Department Washington, D. C. 33 Commanding General Air Materiel Command Wright-Patterson Air Force Base Dayton 2, Ohio Attn: Production Resources MCPB and Flight Research Lab. 34 Commanding General Air Materiel Command Wright-Patterson Air Force Base Dayton 2, Ohio Attn: Materials Lab., MCREXM 35 Director U. S. Department of Interior Bureau of Mines Washington, D. C. 36 Chief Bureau of Mines Eastern Research Station College Park, Maryland 37 National Advisory Committee for Aeronautics 1500 New Hampshire Avenue Washington, D. C. 38 Office of the Chief of Engineers Department of the Army Washington 25, D. C. Attn: Eng. Res. and Dev. Div. Military Oper. 39 U. S. Atomic Energy Commission Technical Information Service P. O. Box 62 Oak Ridge, Tennessee Attn: Chief, Library Branch v

Copy No. Contractor 40 District Chief Detroit Ordnance District 574 E. Woodbridge Detroit 31, Michigan 41 Masaachusetts Institute of Technology Cambridge, Massachusetts Via: Boston Ordnance District 42 Commanding Officer Watertown Arsenal Watertown 72, Massachusetts Attn: Technical Representative 43-44-45- Commanding Officer 46-47-48- Watertown Arsenal 49-50 Watertown 72, Massachusetts Attn: Laboratory 51 Dr. James E. Bryson Office of Naval Research 844 N. Rush Street Chicago 11, Illinois 52 Ford Motor Company 3000 Schaefer Road Dearborn, Michigan Attn: Mr. R. Lesman Supervisor, Development Section Manufacturing Engineering Department Engine and Foundry Division 53-54 Engineering Research Institute Project File University of Michigan Ann Arbor, Michigan Initial distribution has been made of this report in accordance with the distribution list. Additional distribution without recourse to the Ordnance Office may be made to United States military organizations, and to such of their contractors as they certify to be cleared to receive this report and to need it in the furtherance of a military contract. vi

ENGINEERING RESEARCH INSTITUTE ~ UNIVERSITY OF MICHIGAN MECHANICAL PROPERTIES OF MACHINABILITY PROGRAM WORK MATERIALS Four alloys of titanium (one alloy not yet specified), hot-rolled SAE 1045 steel, and type 304 stainless steel were selected as work materials to be studied in the machinability investigation. Tensile specimens have been made and tested and Brinell hardness tests run to provide supporting information on the materials as machined. The results of these tests are presented below. In addition to these mechanical property tests, work is under way to determine tension impact and combined compression and torsion properties. The latter will be presented in a later report. Tensile Properties Standard 0.505-inch diameter tensile specimens were prepared and tested in a 60,000-pound Baldwin Tate Emery Universal Testing Machine. The titanium specimens were prepared from 1-inch diameter bars in the "asreceived" condition. The SAE 1045 specimens were prepared from the center of 4-inch diameter hot-rolled bars. The type 304 stainless specimens were prepared from the center of 3-inch diameter hot-rolled bars. Three specimens were tested of each material except in the case of the stainless, for which only two were tested. The results of the tensile tests are given in Table I. The data in Table I are self-explanatory. Substantial anisotropy was observed in the RC-130B and the Ti-150A titanium alloys, as manifested in elliptical fractures with the major axis approximately one-third greater than the minor axis. Curves of average stress versus average strain are shown in Figures 1 to 14 inclusive for each of the fourteen tensile tests. All three titanium alloys exhibited a very sharp yield point followed by a slight yield point elongation.

TABLE I TENSILE PROPERTIES OF WORK MATERIALS Sample Yield Tensile Breaking Per Cent Per Cent Reduction Number Strength* Strength Strength Elongation of Area 304 S. S. 1 37,500 85,500 55,000 64.5 77.4 304 S. S. 2 41,000 85,700 54,500 62.7 77.4 SAE 1045 1 48,600 101,200 91,000 21.5 3.0 SAE 1045 2 48,800 101,800 92,500 21.7 34.4 SAE 1045 3 53,000 101,700 93,500 22.5 34.6 D Ti-75A 1 60,000 82,000 66,000 28.0 47.1 Ti-75A 2 57,400 82,100 65,500 28.5 48.6 Ti-75A 3 57,700 82,000 65,500 27.7 45.8 RC-130B 1 139,000** 155,500 122,500 18.5 41.9 RC-130B 2 139,400** 155,000 126,200 17.7 37.9 RC-130B 3 139,400** 155,200 121,700 18.3 45.3 Ti-150A 1 131,700 141,000 97,200 25.0 55.8 Ti-150A 2 132,500 140,200 99,200 24.7 54.5 Ti-150A 3 130,000 140,400 97,400 25.0 55.1 * Yield strength determined by 0.2% offset method. * Yield point value.

ENGINEERING RESEARCH INSTITUTE ~ UNIVERSITY OF MICHIGAN Composite results from all specimens for each material are shown plotted as average stress versus natural strain (i.e., the logarithm of one plus the engineering strain) in the five curves of Figures 15 to 19 inclusive. There appears to be a good correlation between the slopes of these curves near fracture with the steepness of the curves of tool life versus side rake angle (Figure 11, Report No. 1) as the side rake angle is increased toward the optimum. The type 304 stainless steel shows the sharpest optimum, while the SAE 1045 steel shows the least. There is a theoretical basis for this correlation, providing it can be demonstrated that the shear strain is of the same magnitude in the chip formation and near the fracture of the tensile test. Brinell Hardness Tests Brinell hardness tests were made over a range of loads on all five work materials. The results are summarized in Table II. TABLE II BHN AND MEYER EXPONENTS Meyer Exponent, Work Material BHN* ** Ti 75A 217 2.41 RC 130B 331 2.37 Ti 150A 302 2.27 304 S.So 174 2.32 SAE 1045 201 2.25 * 3000-kg load. ** Load = adn. Hardness values are reported in the second column for a 3000-kg testing load. The third column gives the Meyer exponents as used in the formula: ~ ~~~~~~~~~~~3~

ENGINEERING RESEARCH INSTITUTE ~ UNIVERSITY OF MICHIGAN Load = adn, where d = diameter of impression in m.m. a = proportionality constant determined by material and load units. ___________________________k________________________4_

TENSILE TEST for Ti-75 A (Averoge Stress vs. Averoge Strain) - - - - - -~~NO. I 140 ~ - ~ ~-~ ~ 120 - - -..~~ ~ ~ ~ 100 - - -- -- - 2 _ __-_____ 80...... ~~ U,,. - ~~~~~ 9201 041 -354

TENSILE TEST for TI-75A (Average Stress v,.Average Strain) NO. 2 1.- -. -.-.-. 140~ ~ ~~~~~ ~~~L~~ ~ ~ I I I I I I - I I I- 80 i- - - - ~ 60.050 0.15.200.250.3.0 AVERAGE STRAIN, INCHES/INCH Fig.. 2

TENSILE TEST for Ti-75A (Averoge Stress vs.Average Strain) |_______|_|_|______ NO. 3 140- - 120 - -~ - - L I00 1', 11 0 so LL S 60 -~~ -~~-~-~ 20 4050..5.200 250.300 5O.000.20 2C50.0 AVERAGE STRAIN, INCHES/INCH Fig. 3

TENSILE TEST for RC-130B (Average Stress vs. Average Strain) 1_^^^^^^F ~~~~~I I I II I I I - ~~"'~~ NO.I 140 120 CL too.. 80 ~~ - - - - - -n Co j 60 - - ~ ~ I I - I- 00 20 - -~.050.. 150.200.250.300 AVERAGE STRAIN, INCHES/INCH Fig. 4

TENSILE TEST for RC-130B (Average Stress vs. Average Strain) ___ _^~^S.. NO.2 14,,, 120 -.-. —.-. o- K)0 - 0, ~~~~~ 0 0 tlJ 80 60 0 40 1- — ~ -,-~-~20.050.100.150.200.250.3)0 AVERAGE STRAIN, INCHES/INCH Fig. 5 4~~~~.5 IO 10.0 20.0 ~~~~~AEAE STR I N -NHSIC -- --—. h~~~~~~~~~~~~~~~~~~i.5

TENSILE TEST for RC-1308 (Average Stress vs.Average Strain) mI mm~ mm mmNO.3 120, 00 m m mmm 0 0 0 60 0 - mm 20.050. 0.150.200.250.300 AVERAGE STRAIN, INCHES/INCH Fig. 6

TENSILE TEST for Ti-50A (Averoge Stress vs.Average Strain) - - - - - - I NO. I 14 120 ~ - - - - -~ cU - - I 10 0 CO),d 0: 60 -, -I - - -.050.100.150.200.250.300 AVERAGE STRAIN, INCHES/INCH Fig. 7

TENSILE TEST for Ti-150A (Average Stress vs.Average Strain) NO. 2 14 -- Q,100' ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 120 80m1' - - i 60 II o.) 20 4 4.00.10.H:20-.2 0.3-0 AVERAGE STRAIN, INCHES/INCH Fiq. 8

TENSILE TEST for Ti-150A (Average Stress vs.Averoge Strain) 140 _ _"P ^ T " N O. 3 120 60 i. -i - - - - II e 100 CO w =, I I................_ __. _ I I I _ 40.. 2~ I I I ~ ~ ~ ~ ~ ~ ~ ~ ~^ ~ -~ ~ ~ I i1 201~~~~~~ 3 - - - - - - - m__ 050.1 00.150.200.250.300 AVERAGE STRAIN, INCHES/INCH Fig. 9

TENSILE TEST for S.A.E.1045 (Average Stress vs. Average Strain) NO., 140. m 120 - - --- - co w 1H a 40.. 201 4 60.050.100.150.200.250.300 AVERAGE STRAIN, INCHES/INCH Fig. 10

TENSILE TEST for S.A.E.1045 (Average Stress vs.Average Strain) NO. 2 140120~ 00 80 00 -- 00 -....050.100.150.200.250.300' rr.050.100.150.200.250.300 AVERAGE STRAIN, INCHES/INCH Fiq. II

TENSILE TEST for S.A.E.1045 (Average Stres8 vs Average Strai. ) NO. 3 140L - - - -1 - 14 120 - ~ - ~ - o100 - - - - 80 = 60^~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 0 T1T 20 - -~~- ~ ~mm U)l T 1- I - -- I- m m m 0 O-.050 O.150.200.25.3 Fig. 12 - -- Fig. 12

TENSILE TEST for S.S.304 (Average Stress vs.Average Strain).350.400.450.500.550.600 NO.I I 140 120 O- - I _ - -i - - C,, 100 mm 0 t 60 t, 4 4 20 0...-..-..-...- - -' Inn - I..050.100.150 200.250.300 AVERAGE STRAIN, INCHES/INCH Fig 13

TENSILE TEST for S.S.304 (Average Stress vs.Average Strain). 350.400 450.500.550.600 NO. 2 140C-t - t120 r rI r rr Jr I, ] 80 U) 0 60 20.050.10.150.200.250.300 AVERAGE STRAIN, INCHES/INCH Fig. 14

TENSILE TEST for TI. 75A (Average Stress vs. Average Strain) 280 m - -. - 240 m - - -___ I ________________ OJ 200 60 0 60 pr 80 120___ 4 40- ---—.-.-.-.0m.050.1 00.150.200.250.300 En- NORMAL STRAIN, En = loe( ) Fig. 15

TENSILE TEST for RC. 130 B (Average Stress vs. Average Strain) 280 - - - - 1240 - - - - c200 CQ - 160 0r o I L I 40.050.10.150.200.250.300 ~n -NORMAL STRAIN, ~nlo!g.(~ )/ Fig. 16

TENSILE TEST for TI. 150A (Average Stress vs. Average Strain) 280 _ --- b 240 Q'200 - - - - 0 LJ ~460 l I 1 uI.e:O 120..3 I I 1E 1 I I I I I a.050.10 0.150.200.250.300 En = NORMAL STRAlN. En l,~(loet ) Fig. 17

TENSILE TEST for S.A.E. 1045 (Average Stress vs. Average Strain) 280 m... -—.. 240 "200 a. 0 0 - 0 [I........~~ 0 C) - 160..... C4 120 ~ 4.050.100.150.200.250.300 En = NORMAL STRAIN, Cn=loge& ) ^' Fig. 18

TENSILE TEST for S.S.304 (Average Stress vs. Average Strain) I 1 I I I I.350 AOO.450.500.550.600 280 - - -,240 -~ - - - -. 10 _z__ 0.: 80______ 40 G F n- NORMAL STRAIN, lo= ( Ige. ) Fig. 19

THE UNIVERSITY OF MICHIGAN DATE DUE l) s O- 3