Effects of strength level and loading frequency on very-high-cycle fatigue behavior for a bearing steel

摘要

Rotating bending (52.5 Hz) and ultrasonic (20 kHz) fatigue tests were performed on the specimens of a bearing steel, which were quenched and tempered at 150 ℃, 300 ℃, 450 ℃ and 600 ℃, respectively, to investigate the influence of strength level and loading frequency on the fatigue behavior in very-high-cycle regime. Influences on fatigue resistance of materials, characteristics of S-N curves and transition of crack initiation site were discussed. The specimens with higher strength showed interior fracture mode in very-high-cycle regime and with slight frequency effect, otherwise cracks all initiate from the surface and the fatigue strength was much higher under ultrasonic cycling.