Bearing steel grades from China 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 a high elastic limit. The requirements for the uniformity of the chemical composition of 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 fuel 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. Fully hardened bearing steel is mainly high carbon and 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 production, 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 their hardness and wear resistance. Large bearings that withstand strong impact loads, such as large mill bearings, automotive bearings, mining bearings and railway vehicle bearings.
To improve the hardness, wear resistance and hardenability, some silicon, manganese, molybdenum, etc. such as GCr15SiMn steel are appropriately added.
Bearing stainless steels have high carbon and chromium bearing stainless steels such as 9Cr18, 9Cr18MoV, etc., and medium carbon and chromium stainless bearing steels such as 4Cr13 for the production of corrosion resistant stainless bearings. High temperature bearing steel is used at high temperatures (300-500°C). It requires the 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.
