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What should be paid attention to in bearing appearance inspection?


Various cracks, such as raw material cracks, forging cracks, heat treatment cracks and grinding cracks, will become the source of stress concentration and expand rapidly in the later operation of the bearing, resulting in bearing fracture, which has a great impact on the service life and work safety of the bearing. In fact, the bearing factory has conducted 100% magnetic or radiographic inspection on the components of bearings for important purposes.
Various mechanical scars, such as abrasion, scratch, crush and collision, will cause poor bearing installation, eccentric load and stress concentration, and reduce the rotation accuracy and service life.
Rust, black skin and pitting. The latter two are defects that are easy to store moisture and dirt, which are easy to develop into rust. Corrosion is the pollution source leading to poor installation, early wear and fatigue. Serious corrosion will scrap the bearing.
Peeling and folding, the local combination of these two defects with the base metal is not firm, and decarburization or carbon deficiency often exist around them to varying degrees. The material is easy to collapse, dent or wear, which is very unfavorable to the service life and accuracy of the bearing.
For the riveting or welding quality of the cage, mainly observe whether the rivet head is offset, skewed, loose, missing meat or damaged "Double eyelid", whether the welding position is correct, whether the welding spot is too large or too small, whether the rolling element is stuck due to loose welding or excessive welding, whether the quality of slope pressing, edge closing, caulking and chiseling of some cages is guaranteed, and whether the rolling element can not fall out of the cage and rotate freely. If these points are not satisfactory, small will reduce the bearing noise and rotation accuracy The cage may fall apart, resulting in mechanical failure or accident.
In case of any finding during the above inspection, the bearing shall also not be accepted. In addition, if the typing quality is poor, such as blurred and damaged handwriting, it shall be considered as defective, and it can also be rejected if it is serious. In addition, it is stipulated that there shall be no visible burns (annealing traces) on the bearing assembly surface.

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