Influence of Initial Residual Stress on Material Properties of Bearing Steel During Rolling Contact Fatigue

Rolling contact fatigue (RCF) experiments were performed on AISI M50 bearing balls using a single ball test rig to investigate the evolution of the material properties within the RCF-affected subsurface region. Using a combination of micro-indentation and miniature compression testing methods, the influence of contact stress, initial residual stresses, and the number of contact cycles on the resulting evolution of material properties was investigated. It was found that the balls with initial residual compressive stresses show less change in material properties after RCF loading than the balls without such initial residual stresses. The formation of a light etching region (LER) is shown to not correlate with a decrease in material strength and hardness, but it does serve as a predictor for failure due to spall.