1. All kinds of mechanical scars, such as abrasions, scratches, pressure injuries, bruises, etc., can result in improper bearing  installation http://www.alierbearings.com/brand/skf/index.html, resulting in partial load and stress concentration, resulting in a decrease in rotation accuracy and service life.
2. Rust, black skin and pitting, the latter two are easy to store moisture and dirt defects, which can be easily developed into rust.
Rust is a source of poor installation, early wear and fatigue, and severe rust can cause the bearing to be scrapped.
3, all kinds of crack, crack, such as raw materials, forging, heat treatment of crack crack and grinding cracks, the crack in the process of bearing after operation, will become a source of stress concentration and is expanding fast, cause bearing is broken, and great influence on bearing life and job security.
In fact, the bearing factory has made 100 percent magnetic or radiographic inspection of its components for important bearings.
4, peeling and folding, the two defects of local combined with matrix metal not firm, and its surroundings often exist in different degrees decarburization or poor phenomenon, carbon material easy caving, the indented or wear, bearing life and accuracy very unfavorable.
5, maintains a riveting or welding quality, mainly to see whether it has offset the rivet head, skew, relaxation, lack of meat, or "double eyelid, correct the position of the welding, solder joint is too big or too small, for welding not firm or excessive cause jam phenomenon of roller.