Excellent rolling fatigue life spherical heat treatment steel bearings

摘要

PROBLEM TO BE SOLVED: To provide a spheroidizing heat treated steel material for bearing, which is used for obtaining a bearing having further improved rolling fatigue life.;SOLUTION: The spheroidizing heat treated steel material for bearing satisfies a predetermined chemical component composition. In the surface parallel to the rolling direction of the steel material, when an EPMA line analysis is carried out in the direction vertical to the rolling direction, the standard deviation σ₁ and the average value a₁ of X-ray intensity values of Cr satisfy the relation of formula (1): (standard deviation σ₁ of X-ray intensity values of Cr/average value a₁ of X-ray intensity values of Cr)≤0.25, and at the same time, the standard deviation σ₂ and the average value a₂ of spheroidized cementite particle diameters satisfy the relation of formula (2): (standard deviation σ₂ of spheroidized cementite particle diameters/average value a₂ of spheroidized cementite particle diameters)≤0.15.;COPYRIGHT: (C)2013,JPO&INPIT