Rolling Contact Fatigue Behaviors of Bearing Steels under High Temperature and High Speed Loading Conditions

Abstract

Rolling contact fatigue behavior in SUJ-2 and AISI M50 steels was investigated using a thrust type testing under the conditions; shaft speed of 8 760 rpm, maximum Hertz stress of 476 kgf/mm², and temperatures of 50°C and 150°C. The Weibull distribution of fatigue life at 50°C presented approximately linear line, while the complex Weibull distribution was obtained at 150°C in both SUJ-2 and M50 specimens. The rolling fatigue life of M50 was much longer than that of SUJ-2 at both 50°C and 150°C. The mean fatigue life of SUJ-2 at 150°C was shorter than that at 50°C, whereas the mean life of M50 at 150°C represented to a greater extension compared with the life at 50°C. These results were explained in terms of no hardness decrement on the track in M50 during high temperature rolling contact. Scanning electron microscopy of a flaking on the rolling surface and of a cross section revealed that the flaking in both SUJ-2 and M50 was initiated at plate-like carbides developed during cyclic stressing in rolling contact.