Rolling Contact Fatigue Life of AISI M-50 as a Function of Specific Film Thickness Ratio Using a High Speed RC Rig

Abstract

Rolling contact fatigue (RCF) life of AISI M-50 was investigated as a function of specific film thickness ratio by varying the rolling speed. RCD lives of M-50 were determined using two synthetic lubricants at rolling speeds of 2.5 m/s (98 in/s), 5.0 m/s (196 in/s), 12.5 m/s (491 in/s), and 25 m/s (982 in/s). These correspond to estimated specific film thickness ratios (Λ) of 0.45, 0.75, 1.48, 2.48 and 3.52, respectively. It was found that the RCF life increases substantially in both the mixed and full film lubrication regime while in the boundary regime, the fatigue life is relatively independent of the rolling speed. Results are discussed in terms of the lubrication life factor which is an important parameter in bearing design. It is suggested that the current ASME design guide lubrication factors are conservative, especially in the high speed regime.