BEARING STEEL MATERIAL HAVING SUPERIOR ROLLING FATIGUE CHARACTERISTICS AND A METHOD FOR PRODUCING SAME

摘要

The problem to be addressed is to achieve a bearing steel for obtaining a bearing component having further increased rolling-contact fatigue life. The bearing steel satisfies a predetermined chemical composition, and Si (boundary Si), Mn (boundary Mn), Cr (boundary Cr), Cu (boundary Cu), Ni (boundary Ni), and Mo (boundary Mo) included in a matrix phase region (boundary surface region) from the surface of spheroidized cementite to 20 nm away satisfy the formula (1) below. 9.0 ‰¤ 1.4 × boundary Si + 1.8 × boundary Mn + 5.5 × boundary Cu + 4.2 × boundary Ni + 4.8 × boundary Cr + 5.5 × boundary Mo