High carbon chromium bearing steel

In the GB/T18254 "High Carbon Chromium Bearing Steel" standard, the meaning of high carbon chromium bearing steel includes CCl4, GCrl5, GCrl5SiMn, CCrl5SiMo, GCrl8Mo, etc. At present, the two kinds of materials GCrl5 and GCrl5SiMn are commonly used in the bearing industry, which account for more than 80% of the total amount of bearing steel. Through advanced smelting technology and technology can make the existing high carbon chromium bearing steel with higher purity, by proper heat treatment, it has a uniformly distributed spherical pearlite structure, good cutting performance , excellent hardenability and hardenability. After heat treatment, the resulting microstructure and hardness are more uniform and stable, with high contact fatigue strength and wear resistance, good dimensional stability and a certain corrosion resistance, also its price is relatively cheap. 

So far, high-carbon chromium bearing steel is still an ideal material commonly used in the manufacture of bearing parts in various countries around the world, and it can meet the requirements of bearing operation under general working conditions.

High-carbon chromium bearing steel is widely used in the manufacture of rolling bearing rings and rolling elements. The properties of GCrl5 and GCrl5SiMn are basically the same, but the hardenability of GCrl5SiMn steel is better than that of GCrl5 steel. Therefore, GCrl5SiMn steel should be used for larger-sized bearing parts.

GCrl5 bearing steel is widely used in the manufacture of engine bearings for automobiles, tractors, tanks, and airplanes, and also used in spindle bearings for machine tools and motors, as well as bearings for railway vehicles, mining machinery, and general machinery.

GCrl5SiMn and GCrl5SiMo bearing steel are mainly used to make bearings with relatively large wall thickness. GCrl5SiMn is suitable for manufacturing bearings with a wall thickness in the range of 15mm to 35mm, while GCrl5SiMo bearing steel is suitable for manufacturing bearings with a wall thickness greater than 35mm, such as various large and extra-large bearings, which are mostly used in heavy machine tools and rolling mills which without large impact loads. Because GCrl5SiMn steel has high crack sensitivity and poor impact toughness, thick-walled bearings with large impact loads cannot fully meet the requirements for use. Therefore, the Ministry of Railways first proposed that the use of GCrl5SiMn steel is not allowed for passenger car bearings and the bearings with large wall thickness subjected to large impact loads in rolling mills and mine are also restricted to use GCrl5SiMn steel .Now, hardenability steels of GCr18Mo, GC, 15SiMo have been developed, and their performances are superior to that of GCrl5SiMn steel. They can be used instead of GCrl5SiMn steel in railway bearings, rolling mill bearings, and mining machinery bearings.

GCr4 bearing steel is a restricted hardenability steel, that is, after a suitable heat treatment process, the ideal matching hardness of harder surface and softer core can be obtained, and it has good wear resistance, impact resistance, fracture toughness and high contact fatigue life. GCr4 bearing steel is used to manufacture bearings for railway passenger cars, mines and metallurgical machinery.

GCrl8Mo bearing steel is a kind of bearing steel treated with bainite, which is widely used in the manufacture of bearings for high-speed trains, mining and metallurgical machinery.