GCr15 steel is an alloy content of less good performance, the most widely used high-carbon chromium bearing steel. After quenching and tempering has a high and uniform hardness, good wear resistance, high contact fatigue performance. The cold steel plastic medium, generally cutting, welding performance is poor, sensitive to the formation of white spots, and have a temper brittleness. 
 Chemical / element content (%) 
 C :0.95-1 .05 Mn :0.20-0 .40 Si :0.15-0 .35 S: <= 0.020 P: <= 0.027 Cr :1.30-1 .65 
 The heat treatment system are: steel bar annealing, wire annealing, or 830-840 degree oil quenching. 
 Heat treatment process parameters: 
 1 annealed :790-810-degree heat, furnace cooling to 650 degrees, air-cooled - HB170-207 
 (2) isothermal annealing :790-810 ,710-720-degree heat degree temperature, air-cooled - HB207-229 
 3. Normalizing :900-920-degree heat, air-cooled - HB270-390 
 4 high-temperature tempering :650-700-degree heat, air-cooled - HB229-285 
 5. Quenching: 860-degree heat, oil quenching - HRC62-66 
 6 :150-170-degree low-temperature tempering tempering, air cooling - HRC61-66 
 7. Carbonitriding :820-830-degree permeation 1.5-3 hour, oil quenching, -60 degrees to -70 degrees to +150 degrees cryogenic treatment to +160 tempering, air cooling - HRC ≈ 67 


 Bearing bearing steel is mainly used to manufacture the parts. Such as ball, roller and bearing rings and so on. They are working under a high concentration of alternating load, the ball bearing rings and the contact area between the small, high-speed rotation, while still sliding, the friction may be great. Therefore, bearing steel should have high hardness, wear resistance and fatigue strength of the steel microstructure, chemical composition requirements are very strict, otherwise it will significantly reduce bearing life. Generally the higher the carbon content of bearing steel in the 0.95 to 1.1% range, and add some alloying elements such as chromium and manganese. Mostly ball annealing delivery, need to be hardened before use (about 840 ℃) and low-temperature tempering (150 ℃). (1) manufacturing methods: the quality of bearing steel smelting demanding, and requires strict control of sulfur, phosphorus and non-metallic inclusion content and distribution, because the non-metallic inclusions content and distribution of the life of the great influence of bearing steel . The higher the amount of inclusions, the shorter life expectancy. In order to improve the quality of refining, smelting furnace and has been adopted recently by the ESR, we can use a vacuum metallurgy, vacuum consumable refining new techniques to improve the quality of bearing steel. Ming Yuan Metal Products (Shanghai) Co., Ltd. Tel: 57888255; Fax: 57888225; Mobile: 15221352988.