REPORT ON SUB-ZERO IMPACT STRENGTHS FOR UNILOY 19-9DL AND 19~9DX ALLOYS By A. I. Rush J. W. Freeman Project 2337 May 16, 1955 UNIVERSAL-CYCLOPS STEEL CORPORATION UNIVERSAL DIVISION BRIDGE VILLE, PENNSYLVANIA

SUB-ZERO IMPACT STRENGTHS FOR UNILOY 19 9DL AND 19-9DX ALLOYS Impact tests were carried out at 760, =104~, and -3230F on three samples of 19=9DL alloy and on three samples of 19-9DX alloy. In each case the treatments used were cold drawn stress-relieved, warm worked and stress-relieved, and annealed by air cooling from 1800~F. SUMMARY The impact strengths decreased linearly with decrease in temperature. The annealed material averaged about 10 to 20 foot pounds higher than the cold drawn and warm worked materials, There was little difference between the 19-9DL and 19~9DX materials except for slightly higher strengths for cold drawn 19=9DX material in comparison to the warm worked condition or in comparison to the 19-9DL material cold drawn or warm worked. The annealed materials had an impact strength of about 50 foot pounds at room temperature and 26 foot pounds at -300FFo Cold drawn and warm worked material range from 21 to 35 foot pounds at room temperature and 12 to 14 at 300~F,,

2 TEST MATERIALS Chemical analyses of the two alloys were reported to be as follows: Alloy 19-9DL 19-9DX Heat No. C-6889 C-6595 C.30.31 Mn 1.23 1.28 Si.64.58 S.011.016 P.028.017 Cr 18.95 19.04 W 1.44 1.60 Ni 8.91 8.97 Mo 1.24 1.53 Cu.16.13 Cb + Ta.28 Ti.25.56 The materials received for testing were described as follows: Bar Length Bar Diameter Bar Grade Condition (inches) (inches) Identity Uniloy 19-9DL Annealed by air cooling from 1800~F 30 3/4 5B Warm worked and stressrelieved to AMS 5722 36 3/4 5A Cold drawn and stressrelieved to AMS 5721 36 11/16 2F Uniloy 19-9DX Annealed by air cooling from 1800~F 30 3/4 2D Warm worked and stressrelieved to AMS 5723 36 3/4 1E Cold drawn and stressrelieved to AMS 5724 36 11/16 1G

3 The following room temperature properties were reported for the annealed and warm worked materials: Tensile 0. 2% Offset Reduction Strength Yield Strength Elongation of Area Alloy Condition (psi) (psi) (%) (%) 19-9DL Annealed by air cooling from 1800~F 109,500 50,500 36.5 52.8 19-9DL Warm worked and stressrelieved to A.MS 5722 140,500 119,500 21.0 44. 0 19-9DX Annealed by air cooling from 1800~F 105,000 47,500 34.0 53.0 19-9DX Warm worked and stressrelieved to AMS 5723 133,000 111,400 20.5 42.6 PROCEDURE Standard 0. 394 inch square Charpy V-notch specimens were machined from the center of the stock submittedo The notch was a 45~ V-notch, 0. 079 inches deep, with a bottom radius of 0. 010 inches. The room temperature tests were carried out at a-temperature of 76~F. Tests at -104~F were carried out by immersing the specimens in acetone cooled by dry ice to that temperature. Tests of -323~F were obtained by cooling the specimens in liquid nitrogen. The actual tests were made by removing the samples from the cooling flask with precooled tongs and quickly placing them in the jaws of the Charpy impact tester and breaking them immediately. The impact machine had been recently calibrated to comply with requirements set up for impact testing at low temperatures for Watertown arsenal.

4 RESULTS The data obtained from the tests are given in Table 1 and shown as a function of temperature in Figure 1. In most cases, very close checks were obtained between triplicate samples. In a few cases the spread was somewhat larger than desirable but certainly no more than might have been anticipated for the particular types of material involved. There was really little difference between the 19-9DL and 19-9DX materials. The only exception was somewhat higher values at -100~ and 76~F for the cold drawn and stress relieved 19-9DX material. Impact strengths fell off nearly linearly with temperature. The annealed material showed impact strengths of about 50 pounds at room temperature and about 26 foot pounds at -300~F, whereas the warm worked and cold drawn materials range from 21 to 35 foot pounds at room temperature to between 12 to 14 foot pounds at -300~F,

5 TABLE 1 CHARPY "V" NOTCH IMPACT DATA FOR 19-9DL AND 19-9DX STEELS FOR THE TEMPERATURE RANGE OF -323~F to 76~F Charpy "V" -notch Impact Strength Test (ft. -lbs. ) Bar TempO Specimen Numbers Condition of Material No. (OF) 1 2 3 Average 19-9DL-Heat Noo C6889 Annealed by air cooling from 1800~F 5B 76 53.0 53.0 51o 0 52.5 -104 38.5 39.0 37.0 38.0 -323 23.0 21 5 29.5 24.5 Warm worked and stressrelieved to AMS 5722 5A 76 26.5 26.0 27. 5 27.0 -104 21.0 17.0 18. 0 18.5 -323 11.0 10.5 -- 11.0 Cold drawn and stressrelieved to AMS 5721 2F 76 21.0 21.5 22,0 21.5 -104 18.0 19.5 -- 19.0 -323 10.5 14.5 _14.0 13.0 19-9DX-Heat No. C6595 Annealed by air cooling from 1800~F 2D 76 49, 5 50.0 52.0 50.5 -104 40.0 39.0 37.0 38.5 -323 24.0 24.5 24.0 24.0 Warm worked and stressrelieved to AMS 5723 1E 76 27.0 25.0 23.5 25.0 -104 20.0 24.0 19.0 21.0 -323 13.5 13.5 - 13.5 Cold drawn and stressrelieved to AMS 5724 1G 76 35.0 34.5 34.5 34.5 -104 25.0 24.0 23.0 24.0 -323 12,5 12.5 12,0 12.5

::::::-:::-::-:::::-: -:;:::: -—:::::-:::........::: --:::: --: -..;......-:;:::;::-:..:....:::::: - - -::: ~::::::-::::::::::::: ^^^^^^^^ ^: ^^^^ii ^^^^ ^^^^l^ ^l^^'^^^ i~~~~~i!^^^^^ ^^^:^:^ ^^ ^^^^i^^^^^^^'^ ^iOf ^ ^^E^^!^:^^:!|^^^:^!^~~~~~~~~~~~...ll.^^^i^::!..... ^:^i3::..~^^it^nia~ i:1:::::::1:1^:: 1:^1:1;;^^E:11111::: i! ^E~ ^^E- h ^EE^ ^E::- ^E^ E11:1::: ^E1:1::^::: iEE:^ i:::: ^:::ll I E i10 i^^E111zi I IlliE ^^^^^^^E^^^^^^^^^ ^^:^ ^^^^iiiiii~i~iuiiii^: i^^^^^^^^^^^ ^^ ^:^ ^^^^^^Er:^ it I:I ^1:::::::::: E;!::! 11::!^:^ ^:^: ^ 3^ ^ ^E 3' =~ E = ~::;;E;:^::S;; ^ C::::( l;^!^:;;; 1.1 -: -': 53::;:C; =:I:::fill::