Quench hardened bearing washer for thrust bearing and thrust bearing

摘要

A bearing washer (11) for a thrust bearing (10) manufactured by quench hardening and used without being subjected to grinding after said quench hardening, wherein when a cross-section perpendicular to a rolling contact surface (11A) of said bearing washer (11) is mirror polished and immersed in an etchant obtained by adding a surfactant to a picric acid saturated aqueous solution so as to corrode said mirror polished surface and when a central portion in said cross-section is observed under magnification of 400x using an optical microscope, a region enclosed by prior austenite grain boundary occupies at most 10% of entire field of view.