1. High carbon chromium bearing steel

Various countries around the world use a steel grade equivalent to GCr15 as the basis for bearing steel, aiming to improve the hardenability and meet the demand for thick walled bearing parts. The method is to add appropriate mass fractions of molybdenum (ranging from 0.1%, 0.2%,..., 0.6%) to the composition, adjust or maintain the mass fraction of chromium slightly, and then develop a series of high hardenability high carbon chromium bearing steels. These steel grades are not only suitable for martensitic quenching, but also for bainitic quenching of thick walled bearing parts.

Another development of high carbon chromium bearing steel is to appropriately reduce hardenability and apply medium frequency induction heating, relying on limited hardenability while overall quenching only hardens the surface. It not only has the superior function of carburizing and quenching carbon steel, but also saves the steel cost of alloy carburizing carbon steel and the high cost of carburizing heat treatment. The use of this steel to make railway bearings has achieved excellent results.

2. Chromium free bearing steel

Chromium free bearing steel is a new type of steel developed by China based on its domestic resource characteristics to replace chromium bearing steel. It includes six steel grades: GSiMnV, GSiMnMoV, GSiMnMoV, GSiMnMoVR, GMnMoV, and GMnMoVR. They have good hardenability, hardenability, anti touch fatigue function, and wear resistance. Compared with chromium bearing steel, its external decarburization sensitivity is slightly higher, and its corrosion inhibition and mechanical processing functions are slightly inferior. However, by adopting appropriate measures, it is completely feasible to use this type of steel to replace chromium bearing steel in the production of bearings.

3. Carbon bearing steel

The academic community of foreign bearing steel believes that the primary role of alloy elements in bearing steel is to improve hardenability, and the primary functions of high strength, high hardness, wear resistance, fatigue resistance, etc. are the role of carbon elements. With the development of vacuum degassing technology today, the purity of carbon steel can also be greatly improved. For bearings with small wall thickness, high carbon steel with vacuum degassing can fully meet the requirements. There is now a trend to further expand the scope of use of carbon steel.

4. Carbonized bearing steel

With the development of high-speed aircraft engines, the cracking toughness of fully quenched steel can no longer meet the requirements. For this reason, the United States has announced the release of M50NiL high-temperature carburizing bearing steel, which has particularly good cracking toughness, excellent high-temperature function, high-speed function, impact toughness, wear resistance, and fatigue resistance. Now we are discussing the infiltration of carbon steel with ultra M50NiL.

Article compilation: Jiangmen assembly line www.zs-chsb.com