1. Adhesion and abrasive wear bearing surface failure is the most common types of failure modes. Sliding friction between the bearing parts leading to continued loss of the metal surface, called the sliding wear. Will continue to wear the size and shape of changes in parts, bearings with the gap increases, the working surface morphology deterioration and thus the loss of rotation accuracy, the bearing does not work. Sliding wear can be divided into abrasive wear, adhesive wear, corrosion, wear, fretting wear, the most common abrasive wear and adhesion wear.

Between the bearing parts of the friction surface or metal particles from the external hard surface of the grinding friction wear caused by the phenomenon of belonging to abrasive wear. It is often caused by chiseling the surface of the bearing type or furrow-like abrasions. External hard particles in the air often comes from dust or lubricant impurities. Adhesive wear of the friction surface mainly due to the friction surface profile peaks were Shouli Bu, local frictional heat so that the friction surface temperature, resulting in lubricant film rupture, severe partial melting of the surface layer of metal will be the contact point produces adhesive, tear off, and then the cycle of the process of adhesion, resulting in severe welding friction surface and stuck.
2. Contact fatigue (fatigue wear) contact fatigue failure of various types of bearing failure is the most common failure mode is one of the bearing surface contact stress by repeated cycles caused by the interaction of the failure. Bearing part surface contact fatigue spalling is a fatigue crack from the initiation and expansion into the crack process. First, the initial contact fatigue cracks below the surface from exposure to the maximum orthogonal shear stress generated at, and then extended to the surface pitted like a small flake off or peel off, the former is known as pitting pitting or peeling; the latter is called light layer peeling off. If the initial crack in the hardened layer and heart Ministry junction could result in the early hardening layer peeling off, then known as the hardened layer peeling off.