Effects of fretting wear on rolling contact fatigue life of M50 bearing steel

The current study presents the results and effects of fretting wear on rolling contact fatigue (RCF) life of M50 bearing steel. A fretting wear test rig was designed and developed to induce fretting scars on the surface of standard M50 rods commonly used in a three ball and rod RCF testing machine. The fretting machine was used to induce fretting scars at a Hertzian contact pressure of 1.1 GPa, in the presence of MIL-L-23699 lubricant at a frequency of 10 Hz, slip amplitude of 21 µm for different number of cycles. The fretted rods were then evaluated at a contact pressure of 1.7 and 3.4 GPa in the three ball and rod RCF tester to determine the effect of fretted scar on fatigue life. The results indicate that a fretting scar can reduce the fatigue life at 3.4 GPa by an average of 30 per cent and fretted rods operating at 1.7 GPa behave very similar to an unfretted rod operating at 3.4 GPa.