A Physically Based Endurance Limit Model for Through Hardened and Surface Hardened Bearing Steels

摘要

A physically based model for calculating the load rating of rolling bearings for an infinite life is presented The proposed model is based on the fact that, for bearings operating under EHD conditions, material fatigue can not occur as long as the maximal local shear stress built up in the subsurface region does not exceed the micro-yield shear stress of the steel matrix. The calculation of the local shear stress can account for the presence of, on the one hand, hoop stresses or residual stresses and, on the other hand, on the steel inhomogeneities (nonmetallic inclusions, carbides) that act as stress raisers. The model is applied to investigate the influence of material parameters and operating conditions for various through hardened steels and surface hardened steels (carburized or nitrided).