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Chemical composition and characteristics of bearing Steel GCr15
Feb 23, 2018

The main chemical components of bearing steel are carbon, chromium, silicon, manganese, nickel, molybdenum, vanadium and so on.

I. Carbon effects

Except carburized steel, the carbon content of bearing steel is 0.95-1.15%, which belongs to hypereutectoid composition. Thus, high hardness, high contact fatigue strength and wear resistance can be obtained after quenching and tempering at low temperature. In order to form enough carbides to increase the wear resistance, the carbon content should not be too low, but too high carbon content will increase the non-uniformity of the carbides and make the mechanical properties of the carbides decrease with the formation of reticular carbides.

II. Effect of alloy elements

Chromium is the main chemical component of bearing steel. Chromium can improve hardenability, reduce overheating tendency and improve low-temperature tempering stability. Silicon and manganese in bearing steel mainly improve hardenability. Nickel in Carburized bearing steel can improve the toughness and plasticity of steel. Nickel can improve the fatigue resistance of steel and reduce the sensitivity of steel to notch. Molybdenum in steel can improve hardenability and thermal strength, prevent tempering brittleness and increase corrosion resistance in certain medium. Vanadium increases the strength and yield ratio, especially the ratio limit and elastic limit, and reduces the decarburization sensitivity during heat treatment. Thus the surface quality of bearing steel without chromium and vanadium is improved.