Analysis of Microstructure and Mechanical Properties of Bearing Inner Ring

Abstract

This article selects GCr18Mo steel to make an inner ring of rolling bearing. After isothermal quenching heat treatment, microstructure and mechanical properties are tested. The results show that microstructure and hardness from the surface to the core is uniform. The compositions are lower bainite and carbide, and both of them are small. The length-width ratio of lower bainite needle is about 10, and the average diameter of carbide in is 0.33μm. The hardness ranges from the surface to the core is between 715 HV and 755 HV, the average hardness of the inside and outside surface is 59.9HRC. Stress state of the surface is compressive stress and axial compressive stress is greater than the one of the hoop. Compressive stress in axial direction is about 588MPa, which is about 390MPa in the direction of the ring. After polishing, compressive stress in axial direction is about 483MPa, which is about 231MPa in the direction of the ring.