Rolling contact bearing and a method of producing thereof

Abstract

A rolling contact bearing, in particular, a carbonitrided bearing mainly used for automobile transmissions, being intended that the steel for the bearing contains less amounts of alloy ingredients to keep its good cold working performance, that carbonitriding time is shortened to reduce production costs, and that its rolling fatigue life is extended, in particular, under lubrication with foreign elements. At least the bearing race member of the bearing made of a medium carbon steel consisting essentially of, by weight, 0.4 to 0.8% of C, 0.4 to 0.9% of Si, 0.7 to 1.3% of Mn and 0.5% or less of Cr is formed by cold working. The bearing race member is provided with case-hardened layers thereon obtained via carbonitriding, followed by quenching and tempering. Retained austenite in the case-hardened layers is kept in the range of, by volume, 20 to 40%, and the core portion of the bearing race member has a hardness of HRC58 or less.