1. All kinds of mechanical scars, such as abrasion, scratch, crush, bruise, etc., will cause poor bearing installation, causing eccentric load and stress concentration, resulting in a decline in rotation accuracy and service life.

2, rust, black skin and pitting, the latter two are easy to store moisture and dirt defects, it is easy to develop into rust. The corrosion is the cause of poor installation, early wear and fatigue sources, serious corrosion will make the bearing scrapped.

3, all kinds of cracks, such as raw material cracks, forging cracks, heat treatment cracks and grinding cracks, these cracks in the future bearing operation process, will become the source of stress concentration and rapid expansion, resulting in bearing rupture, bearing life and work safety has a great impact. In fact, for bearings for important purposes, bearing factories have carried out magnetic or radiographic inspection of their constituent parts.

4, peeling and folding, the local combination of these two defects and the base metal is not strong, and the surrounding is often different degrees of decarburization or carbon depletion phenomenon, the material is easy to collapse, depression or wear, the bearing life and accuracy is very unfavorable.

5. The riveting or welding quality of the cage mainly observes whether the rivet head is offset, skewed, loose, lack of meat or "double eyelid", whether the welding position is correct, whether the welding spot is too large or too small, and whether the rolling element is stuck due to weak welding or excessive welding.

The above items are the parts we check in the inspection of imported bearings. In addition to the above-mentioned inspection parts, in addition, if the typing quality is not good, such as blurred handwriting and damage, it should be considered defective, and serious cases may not be accepted.