When the rolling bearing is working, there is point contact or line contact between the rolling elements and the raceway. Under the action of alternating load, there is a large cyclic contact stress between the surfaces, which easily forms a source of fatigue on the surface. The fatigue source produces microcracks. Due to its high hardness and brittleness, microcracks are difficult to develop in depth. They flake off in small particles and have good pitting corrosion on the surface. This is fatigue pitting. In severe cases, the surface will peel off and form pits; if the bearing continues to run, a large area of peeling will be formed. Fatigue pitting will generate shock loads during operation, which will increase the vibration and noise of the equipment. However, fatigue pitting is a normal and inevitable form of failure of rolling bearings. Bearing life refers to the total number of revolutions before the first fatigue spall point occurs. The rated life of the bearing refers to 90% of the life of the bearing without fatigue pitting. (Use the bearing fault detector to diagnose the bearing)