Patent ID: 8793878
Filing Date: 2014-08-05
Classification: C21D,C22C,F16C,Y10T

Abstract:
1. A method for manufacturing a rolling-element bearing, which includes an inner ring having an inner-ring raceway, an outer ring having an outer-ring raceway and a plurality of rolling elements that are rollable on the inner-ring raceway and on the outer-ring raceway, the method comprising: forming the inner ring from a steel having a sulfur content of 0.002 to 0.015 mass % and an oxygen content of less than 15 ppm, subjecting the inner ring to a heat treatment to harden it, which heat treatment ends by performing a final hardening heat treatment step at a predetermined temperature, cold working the inner-ring raceway to generate compressive residual stresses at least in a surface layer of the inner-ring raceway, subjecting the cold-worked inner ring to a bluing treatment to form a blued layer on an outer surface of the inner ring, and subjecting the blued inner ring to a thermal post-treatment process at a temperature below the predetermined temperature of the final hardening heat treatment step.