Knowledge of bearing steel pipes

Bearing steel pipe refers to seamless steel pipe that is hot-rolled or cold-rolled (cold drawn), used for manufacturing ordinary rolling bearing rings. The outer diameter of the steel pipe is 25-180 millimeters, and the wall thickness is 3.5-20 millimeters, divided into two types: ordinary precision and higher precision. Bearing steel is the steel used to manufacture ball bearings, rollers, and bearing rings. Bearings are subjected to tremendous pressure and friction during operation, so bearing steel is required to have high and uniform hardness and wear resistance, as well as high elastic limits. The requirements for the uniformity of chemical composition, content and distribution of non-metallic inclusions, and distribution of carbides in bearing steel are very strict, making it one of the most demanding steel grades in all steel production.

Physical properties of bearing steel pipes

The physical properties of bearing steel mainly depend on the examination of microstructure, decarburization layer, non-metallic inclusions, and low magnification structure. Generally, delivery is made through hot rolling annealing and cold drawing annealing. The delivery status should be specified in the contract. The low magnification structure of steel must be free of shrinkage pores, subcutaneous bubbles, white spots, and microscopic pores. The central looseness and general looseness shall not exceed level 1.5, and the segregation shall not exceed level 2. The annealed structure of steel should be uniformly distributed fine-grained pearlite. The depth of decarburization layer, non-metallic inclusions, and unevenness of carbides should comply with the relevant national standards.