Material Stress and Heat Treatment of Rolling Bearing Steels

Abstract A stress analysis for a Hertzian contact of ball on groove is presented. The subsurface stresses, the equivalent stresses and the effect of residual stresses are shown by diagrams. Based on this analysis the requirements for materials applied in rolling element bearings are derived. The basic properties of the bearing steels, the predominantly used materials for rolling element bearing components are described. The influence of the austenitizing temperature, method of quenching and tempering temperature on the material properties is shown on the example of the bearing steel 100CrMnSi6-4. It is demonstrated how the requirements derived by these results can be fulfilled by modern equipment for industrial heat treating. It is also shown, to which extent residual stresses can be induced by different quenching procedures and that bainitic hardening can result in advantages especially for bearing applications.