A PHYSICALLY-BASED MODEL FOR ENDURANCE LIMIT OF BEARING STEELS

Available models are not suitable for calculating the load rating of b earings when an infinite life is required. This paper presents a new m odel that has been developed from a detailed analysis of the damage me chanism responsible for failure of bearings operating under EHD pure r olling conditions. It is based on the comparison between the local she ar stress concentration built up around inhomogeneities present in ste els and the microyield stress of the martensitic matrix. The predictio ns of this model are in good agreement with some literature data conce rning the fatigue limit of bearing steels. Finally, the influence of m aterial parameters and operating conditions on the endurance limit of bearings is investigatedAvailable models are not suitable for calculat ing the load rating of bearings when an infinite life is required. Thi s paper presents a new model that has been developed from a detailed a nalysis of the damage mechanism responsible for failure of bearings op erating under EHD pure rolling conditions. It is based on the comparis on between the local shear stress concentration built up around inhomo geneities present in steels and the microyield stress of the martensit ic matrix. The predictions of this model are in good agreement with so me literature data concerning the fatigue limit of bearing steels. Fin ally, the influence of material parameters and operating conditions on the endurance limit of bearings is investigated.