Bearing steel is used to make bearing balls, roller and rings. Usually, bearings under great pressure and friction during operation, therefore, steel must has a strong performance of have high, uniform hardness, wear resistance and high elastic limit.
Some common bearing steel gauge were incorporated into the international standard by ISO. Bearing steel were divided into fully hardened bearing steel, surface hardened bearing steel, stainless bearing steel, high-temperature bearing steel, a total of 4 categories and 17 different types. In some country, they also add a type of bearing steel or alloys for special purposes.
In China, approved classification method of dividing bearing steel category is similar to those of ISO. respectively corresponding to four categories: high-carbon chromium bearing steel, carburized bearing steel, corrosion-resistant bearing steel, and high-temperature bearing steel.
High-carbon chromium bearing steel GCr15, which is the most produced bearing steel in the global world. Carbon Wc is about 1%, and chromium content Wcr is about 1.5%. It takes up more than 80% of total production of bearing steel. Usually, when purchasing bearing steel without any special instructions, seller will offer GCr15.