STEEL MATERIAL WITH EXCELLENT ROLLING FATIGUE LIFE AND METHOD OF PRODUCING THE SAME

摘要

Provided are a steel having excellent rolling contact fatigue life and the manufacturing method thereof. The steel consists essentially of 0.7 to 1.1% C, 0.2 to 2.0% Si, 0.4 to 2.5% Mn, 1.6 to 4.0% Cr, 0.1% or more and less than 0.5% Mo, 0.010 to 0.050% Al, by mass, and balance of Fe and inevitable impurities, is treated by quenching and tempering, has residual cementite grain sizes ranging from 0.05 to 1.5 µm, and has prior-austenite grain sizes of 30 µm or smaller. When the steel is used to bearing steel, the bearing life extends even under service in more severe environments.