China bearing steel grades include G8Cr15, GCr15, GCr15SiMn, GCr15SiMo and GCr18Mo.
Bearing steel, also known as high carbon chromium steel, has a carbon content of about 1% and a chromium content of 0.5% to 1.65%.
This steel has high and uniform hardness and wear resistance, as well as high elastic limit. The requirements for the uniformity of the chemical composition of the bearing steel, the content and distribution of non-metallic inclusions, and the distribution of carbides are very strict, and it is one of the most demanding steel grades in all steel production.
Bearing steel can also be used to make precision measuring tools, cold stamping dies, machine tool screws, precision parts such as dies, gauges, taps and diesel oil pumps.
Bearing steel is divided into fully hardened bearing steel, carburized bearing steel, stainless bearing steel and high temperature bearing steel according to chemical composition, performance, processing technology and use. The fully hardened bearing steel is mainly high carbon chromium steel, such as GCr15, which has a carbon content of about 1% and a chromium content of about 1.5%. This type of bearing steel has the largest output, accounting for more than 95% of all bearing steel production. Carburized bearing steel is a chromium, nickel and molybdenum alloy structural steel with a carbon content of 0.08-0.23%. The surface of the bearing parts is carbonitrided to improve its hardness and wear resistance. Large bearings that withstand strong impact loads, such as large mill bearings, automotive bearings, mining bearings and railway vehicle bearings.
In order to improve hardness, wear resistance and hardenability, some silicon, manganese, molybdenum, etc., are suitably added, such as GCr15SiMn Steel.
Stainless bearing steels have high carbon chromium stainless bearing steels, such as 9Cr18, 9Cr18MoV, etc., and medium carbon chromium stainless bearing steels, such as 4Cr13, for the production of stainless corrosion resistant bearings. High-temperature bearing steel is used at high temperature (300-500 °C). It requires steel to have certain red hardness and wear resistance, most of them use high-speed tool steel, such as W18Cr4V, W9Cr4V, W6Mo5Cr4V2, Cr14Mo4 and Cr4Mo4V.