Bearing Steel Classification

Bearing steel is steel used to make balls, rollers and bearing collars. Bearing steel has high and uniform hardness and wear resistance, as well as high elastic limits. The uniformity of the chemical composition of bearing steel, the content and distribution of non-metallic inclusions, the distribution of carbide and so on are very strict, is one of the most stringent steel production requirements, so the requirements of bearing steel should have: high hardness, uniform hardness, high elastic limit, high contact fatigue strength, the necessary toughness, a certain quenchability, corrosion resistance in the atmosphere lubricant.

Bearing steel is divided into: full-hardened bearing steel, surface hardened bearing steel, rust-free bearing steel, high-temperature bearing steel and other four categories of a total of 17 steel numbers.

At present, the world's bearing steel mainly has 5 categories, namely, high carbon chrome bearing steel, carbonized bearing steel, rust-free bearing steel, high-temperature bearing steel, medium carbon bearing steel.

Bearing steel is also particularly widely used, usually we divide the bearing steel into four categories: high carbon chrome bearing steel, carbonizing bearing steel, rust-free bearing steel and high-temperature bearing steel, of which the high carbon chromium bearing steel in the brand GCr15 production and use of the largest.

1) High carbon chromium bearing steel is suitable for inner jacket rings and rolling bodies, tempering hardness is HRC61-64. Grades GCr15, GCr15SiMn, etc., require sphinse p, S content is not greater than 0.025%, and limit the content of residual elements such as Ni, Cu, steel oxygen content control in (12 X 10-6) %. Provisions for acid immersion low-times tissue inspection, quenching break inspection according to the requirements, non-metallic inclusions, micropores, microtissue, carbon ation unevenness, decarbonization depth inspection, for cold and stamping steel to carry out top forging inspection. Such steels are smelted by electric furnaces and require vacuum degassing or other refining methods. This type of steel is suitable for the manufacture of general-purpose bearing collars and rolling bodies.

2) Carburizing bearing steel is suitable for bearings with shock and seismic requirements. Grades G20CrMo, G20CrNiMo G20CrN12Mo, etc., belong to low-carbon alloy structure steel. The smelting method, chemical composition, mechanical properties, low-fold tissue (acid dip low times and tower hair pattern), high-fold tissue (non-metal inclusions, crystal grain size, microtissue) set strict requirements, and some steel provisions on a step-by-step ultrasonic inspection, end quenching test. More than made of rods, used in agriculture and other machinery and other sectors.

3) Rust-free bearing steel is suitable for bearings with non-rust and anti-atmospheric corrosion, as well as precision micro bearings. Grades G95Cr18, G102Cr18Mo, etc., for high-carbon high-chromium Mars body steel, chemical composition, hardness, low-fold tissue and high-fold tissue are strictly stipulated, the use of arc furnace and by the remelting of electric slag (can be used non-vacuum induction furnace or vacuum furnace smelting and remelting by electric slag) process production. Bearings for operating under corrosive conditions.

4) High temperature bearing steel is suitable for high temperature bearings with an operating temperature of 200 degrees C. The brand Name G8Cr4M04V, the provisions of non-vacuum induction furnace or vacuum induction furnace smelting and by the electric slag remelting method of production, strict provisions of chemical composition, especially to limit P, S content, strict testing of high, low-times tissue and decarbonization depth. Bearings for operating at high temperatures.

5) Special bearing materials are suitable for bearings that are resistant to magnetism and corrosion from special media, such as G52 alloys, G60 alloys and self-lubricating graphite steel.