The chemical composition of bearing steel (GCr15) and its effects

The chemical components in bearing steel（GCr15） are mainly carbon, chromium, silicon, manganese, nickel, molybdenum, vanadium and so on.

The main factors affecting the characteristics of bearing steel are carbon and alloying elements

a） The impact of carbon

In addition to carburized steel, the carbon content of general bearing steel is 0.95-1.15%, which belongs to a hypereutectoid component. In this way, high hardness, high contact fatigue strength and wear resistance can be obtained after quenching and low temperature tempering. In order to form enough carbide to increase wear resistance, the carbon content should not be too low, yet extremely high carbon content will increase the unevenness of the carbides, and will form a network of carbides, which will degrade its mechanical properties.

b ）The effects of alloying elements

Chromium is the main chemical component of bearing steel. Chromium can improve hardenability, reduce overheating tendency, and improve low temperature tempering stability. The main role of silicon and manganese in bearing steel is to improve hardenability. Nickel can improve the toughness and plasticity of steel in carburized bearing steel. Nickel can improve the fatigue resistance of steel and reduce the sensitivity of steel to notches. Molybdenum can improve hardenability and thermal strength in steel, prevent temper brittleness, and increase corrosion resistance in certain media. Vanadium in bearing steel can increase the strength and yield ratio, especially the ratio limit and elastic limit, which can reduce the decarburization sensitivity during heat treatment, thereby improving the surface quality. The chromium-free vanadium-containing bearing steel has a high dispersion and good performance