*2.1.2 Common failure forms*

Rolling bearing, as a component part of the mechanical equipment, will inevitably produce a loss. Even if their own quality, including material processing and other aspects are very excellent, and there is no working condition failure, after a period of use, there will still be fatigue and wear, and other conditions. Master the common failure form of bearings, and can repair and replace the bearing elements in advance to extend the service life [10].

### 1.Fatigue peeling

Under the repeated action of various forces, rolling bearing outer ring and inner ring, the maximum force part appear crack, surface metal may show point peeling, in serious cases even sheet peeling, this phenomenon, we call fatigue peeling. Fatigue peeling is the most common without special circumstances.

### 2. Surface plastic deformation

The surface of the rolling bearing will form mechanical damage because of the action of pressure, or hard objects involved in the rolling bearing, and the damage continues to expand, which will cause vibration, noise, etc. so that the damage speed of the bearing is greatly accelerated. This phenomenon is surface plastic deformation.
