The finishing of the ring rolling surface refers to the final fine processing of the bearing raceway (or groove) after grinding. The reason for finishing is that the quality of the rolling surface of the ring directly affects the working performance and service life of the bearing. However, due to the precision of the grinding machine, vibration, deformation, high temperature and high productivity during grinding, it is generally difficult to achieve the surface roughness, allowable waviness, required geometric shape accuracy and physical and mechanical properties of the surface layer specified by the rolling surface. Therefore, the rolling surface of the ring still needs to be finished after grinding to meet the requirements of technical conditions.

After finishing, the following technical requirements are generally required:

1. Reduce the surface roughness value. Tests show that the roughness of the ring rolling surface has a direct impact on the service life of the bearing. However, a lower surface roughness value is not always better. Typically, achieving Ra 0.08-0.04 μm is more suitable.

2. Reduce circular deviation (i.e. reduce waviness and improve facet). The circular deviation of the ring rolling surface, especially the influence of waviness on bearing vibration, noise, rotation accuracy, load capacity and service life, has been confirmed by many tests and has been highly valued by the bearing industry, which has put forward specific requirements and taken effective measures.

3. Improve the geometric shape accuracy of the groove (raceway) cross section. Both theory and practice show that the geometric shape accuracy of the groove (raceway) has an important influence on the life of the bearing. At present, higher and higher requirements are placed on the shape accuracy of the groove arc profile and the raceway convex profile.

4. Improve the physical and mechanical properties of the rolling surface. Because the rolling surface is affected by the grinding force and grinding heat as high as 750-1200°C during grinding, the metal crystal structure of the surface layer (4-6μm) is destroyed and tensile stress is easily generated. Therefore, one of the tasks of finishing is to remove the defective layer and improve the surface contact fatigue strength and bearing life.