The metallurgical quality of bearing steel has the following eight basic requirements;
① Strict chemical composition requirements;
② Higher dimensional accuracy requirements, for hot-rolled annealed bars forged on high-speed upsetting machines, there should be higher requirements for dimensional accuracy;
③Specially strict purity requirements;
④ Strict requirements for low-magnification and microscopic (high-magnification) structures;
⑤Specially strict requirements for surface defects and internal defects: surface defects include surface cracks, surface slag inclusions, burrs, folds, scars, oxide scales, etc.; internal defects include shrinkage cavities, bubbles, white spots, overburning, and severe porosity And segregation, microporosity, etc.;
⑥ Strict requirements for carbide inhomogeneity;
⑦Strict requirements on the depth of surface decarburization layer;
⑧Other requirements: such as smelting method of bearing steel, oxygen content, annealing hardness, fracture, residual elements, spark test, delivery status, etc.