Hardness and Application of Bearing Steel

Hardness range and application of bearing steel

The hardness range of bearing steel is usually between Rockwell hardness HRC 62-64, and the specific hardness value depends on different steel grades and heat 

treatment processes. For example, the hardness range of GCr15 bearing steel is HRC 62-64 1. The high hardness of bearing steel is one of its important characte-

ristics, which requires strict control of the heat treatment process during manufacturing to avoid entering the blue brittle zone and high-temperature brittle zone, 

thereby ensuring its hardness and mechanical properties.

Classification and Application of Bearing Steel

Bearing steel can be classified into the following categories based on its composition and application:

High carbon chromium bearing steel: This is the most commonly used bearing steel, with high and uniform hardness and wear resistance. Its carbon content is 

about 1% and chromium content is about 0.6%. This type of steel is suitable for manufacturing balls, rollers, and bearing rings.

Carbonized bearing steel: used to manufacture bearing components that operate under impact loads or vibration conditions, such as automobiles, locomotives, 

construction machinery, etc. The surface layer can be hardened to high hardness, while the core maintains appropriate toughness and strength.

Medium carbon bearing steel: suitable for applications that can withstand greater impacts, such as low-speed large components with lower hardness requirem-

ents. Some newly developed varieties of medium carbon steel, such as GCr15, can be used for the manufacturing of bearing components of various sizes.

Chemical composition and heat treatment process of bearing steel

The chemical composition of bearing steel has a significant impact on its properties. The main components of high carbon chromium bearing steel include carbon 

(C) and chromium (Cr), and sometimes other alloying elements such as molybdenum (Mo) and manganese (Mn). The heat treatment process is crucial for the 

hardness and performance of bearing steel. Common heat treatment processes include quenching and tempering, with specific temperatures and times varying 

depending on the steel grade. For example, the quenching temperature of GCr15 is 820-846 ℃, and the tempering temperature is 150-160 ℃.

In summary, bearing steel is widely used in the manufacturing of bearings for various mechanical equipment due to its high hardness, uniform hardness, and 

wear resistance. Its chemical composition and heat treatment process have a significant impact on its performance.