Bearing Steel Tube Knowledge
The bearing steel tube refers to the seamless steel pipe which is hot-rolled or cold-rolled (cold-drawn). It is used for making plain rolling bearing rings. The outer diameter of steel pipe is 25mm to 180mm. Thickness is 3.5mm to 20mm. It can be divided into ordinary precision and higher precision. Bearing steel is the steel used to make ball bearings, rollers and bearing rings. Bearing in the work under great pressure and friction, so the bearing steel is required to have high and uniform hardness and wear resistance, as well as high elastic limit. The uniformity of chemical composition, the content and distribution of non-metallic inclusions and the distribution of carbides of bearing steel are strictly required. It is one of the most demanding types of steel in all steel production.
The physical properties of bearing steel mainly include inspection of microstructure, decarburization layer, non-metallic inclusion and low-strength structure. In general, hot rolling annealing and cold drawing annealing are used for delivery. The state of delivery shall be indicated in the contract. The microstructure of steel must be free from shrinkage, subcutaneous bubbles, white spots and micropores. The e central porosity and general porosity shall not exceed grade 1.5, and the segregation shall not exceed grade 2. The annealed structure of steel should be fine granular pearlite with uniform distribution. The depth of decarburization layer, non-metallic inclusion and carbide inhomogeneity shall conform to the relevant national standards.