Effect of cold treatment process on roundness of bearing ring

Abstract

In the heat treatment of the bearing ring, due to the different degree of thermal expansion of the outer surface and inner metal of the bearing ring, and the large thermal stress and tissue stress generated in the ring, resulting in serious deformation of the ring in the diameter direction and increased roundness error. For these problems, the heat treatment test of the bearing ring was carried out, with the cold treatment process added to the heat treatment. The effect of cold treatment on the residual stress, retained austenite and roundness of the bearing ring was analyzed. The research results show that: because the degree of deformation of the bearing ring is affected by the residual stress, the cold treatment process can significantly improve the residual stress on the bearing ring surface and reduce the deformation. The cold treatment process can accelerate the transformation from retained austenite to martensite in the bearing ring, reduce the content of retained austenite, refine the martensite structure and promote the precipitation of network carbide. The cold treatment after quenching also can improve the roundness accuracy of the bear outer ring and the bearing ring raceway, and ensure the processing quality and dimensional stability, which will be a significant benefit in industrial applications.