The steel ball manufacturer talk about the technical standard of bearing steel ball. Bearing is subject to greater pressure and friction during use, which requires bearing steel to have higher uniform hardness, wear resistance and higher fatigue. The uniformity of chemical composition of bearing steel, the content and division of non-metallic inclusions, and the division of carbides are quite strict. Bearing steel is divided into 17 grades, including fully hardened bearing steel, surface hardened bearing steel, stainless steel bearing steel and high-temperature bearing steel. According to the above basic requirements for bearing steel, the following basic requirements are proposed for the metallurgical quality of bearing steel; ① Strict chemical composition requirements. The steel for general bearing engineering is usually high carbon chromium bearing steel, that is, hypereutectoid steel with a carbon content of 1% up and down, about 1.5% chromium, and a small amount of manganese and silicon. Chromium can improve heat treatment performance, hardenability, microstructure uniformity, tempering stability, and rust resistance and grinding performance of steel. ② High dimensional accuracy is required. For hot-rolled annealed bars forged on high-speed upsetting and forging machines, higher dimensional accuracy should be required. Steel for rolling bearings specifies that the processing accuracy of building steel is high, mainly because most bearing parts are formed by bearing. In order to save materials and improve labor efficiency, most bearing rings are forged, steel balls are formed by cold heading or hot rolling, and small rollers are also formed by cold heading. If the processing accuracy of construction steel is not high, it is difficult to accurately calculate the blanking size and weight, and the product quality of bearing parts cannot be guaranteed, which is also easy to cause damage to equipment and molds. Steel ball manufacturer ③ Especially strict cleanliness requirements. The purity of steel refers to the number of non-metallic inclusions in steel. The greater the purity, the lower the non-metallic inclusions in steel. The harmful inclusions such as oxides and silicates in bearing steel are the root cause of bearing fatigue and falling off at the initial stage and significantly reducing the service life of the bearing. Especially the brittle inclusion is harmful, because it is easy to peel off from the metal matrix during the processing, which seriously affects the surface quality of bearing parts after finishing. Therefore, in order to improve the service life and reliability of bearings, the content of inclusions in bearing steel must be reduced. ④ Strict requirements for macrostructure and microstructure (macrostructure). The macrostructure of bearing steel refers to loose, central loose and carbide. The microscopic (macrostructure) mechanism includes the annealing mechanism, carbide network, strip and liquid precipitation of steel. Carbide liquid is hard and brittle, and its harm is similar to that of brittle inclusion. The network carbide reduces the impact toughness of the steel, so that its mechanism is uneven, and it is easy to deform and crack during quenching. Strip carbides endanger the annealing and quenching tempering mechanisms and their contact fatigue. The quality of macrostructure and macrostructure has an impact on the performance and service life of roller bearings. Therefore, there are clear provisions on macrostructure and macrostructure in the bearing material standards.