Patent ID: 7691212
Filing Date: 2010-04-06
Classification: C23C,Y10S

Abstract:
1. A rolling element which is made from a steel, the steel comprising 0.5 to 1.5 wt % carbon; 0.3 to 1.5 wt % Cr; and a total amount of 0.2 to 2.0 wt % of one or more alloy elements selected from the group consisting of V, Ti, Zr, Nb, Ta and Hf; wherein 0.4 to 4.0% by volume of carbides of said alloy elements having an average particle diameter of 0.2 to 5 μm are dispersed, wherein the rolling element has a rolling contact surface layer, the rolling contact surface layer has a quench hardened layer which has been subjected to induction hardening, the quench hardened layer has a martensite parent phase and the martensite parent phase has a soluble carbon concentration of 0.3 to 0.8 wt %, and said carbides in an amount of 0.4 to 4.0% by volume and cementite in an amount of 2 to 15% by volume are dispersed within the martensite parent phase, wherein the 2 to 15% by volume of the cementite contains 2.5 to 10 wt % Cr as an average composition.