Rolling-Element Fatigue Life of AISI M-50 and 18-4-1 Balls.
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CEN TER
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Rolling-element fatigue studies were conducted with VIM-VAR AISI M-50, EFR 18-4-1, and VAR 18-4-1. Groups of 12.7-mm 12-in. diameter balls of each material were tested in the five-ball fatigue tester. Test conditions included a load of 1540 N 347 lbf giving a maximum Hertz stress of 5520 MPa 800 000 psi, a shaft speed of 10 700 rpm, and a contact angle of 30 deg. Tests were run at a race temperature of 339 K 150 deg F with a type II ester MIL-L-23699 lubricant. The rolling-element fatigue life of VIM-VAR AISI M-50 was not significantly different from that of EFR 18-4-1 or VAR 18-4-1 based on a statistical comparison of the test results.
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