Method of forming bearing ring resistant to season cracking

Abstract

A method sets a retained austenite amount of an edge of a bearing ring of a bearing to between 3% or more and 20% or less. The method includes exposing the bearing ring to an environment having a temperature in the range of 850° C. to 930° C., an ammonia concentration, and a carbon concentration C·P in a range of 0.9 to 1.1%, for a period of not more than 5 hours. The ammonia concentration of the environment is in a range of 4 to 7 CFH. The temperature of the environment is then reduced to a temperature in a range of 800° C. to 830° C. for a second period of at least 30 minutes. The bearing ring is next quenched in oil and then heat treated in an environment set to a temperature of 160° C. to 200° C. and then air cooled.

Dependencies are inferred from the claim text.