Influences of Heat Treatment and Residual Stress on Rolling Fatigue of Steel Ball

Abstract

A rolling bearing is an important machine element upon which industries and our daily life are based. The contact surfaces of bearing rings and rolling elements are expected to have high reliability against repeated load. As the material for steel balls used for rolling bearing such as deep groove ball bearing, high carbon-chromium material for bearing (JIS SUJ2) is widely used. The authors have been focusing on the steel ball, have developed materials to gain higher reliability, and have clarified the effect of characteristics associated with the rolling fatigue. In this report the influence of heat treatment and residual stress formed by peening process on rolling fatigue life is examined with various steel balls prepared with various heat treatment conditions (quenching & tempering temperatures), peening conditions, and manufacturing process. Consequently, we clarified the effect of hardness and metal structure on the rolling fatigue life of the steel ball, and derived the most appropriate heat treatment condition. We also clarified the residual stress applied during peening process shortened the fatigue life of steel ball, and proposed an optimum residual stress distribution.