Patent ID: 7413704

Claim:
A case hardening bearing steel having excellent toughness and an excellent rolling contact fatigue life in intermediate temperature comprising: C of 0.15 to 0.30 mass percent, Si of 0.5 to 2.0 mass percent, Mn of 0.3 to 2.0 mass percent, Cr of 1.75 to 2.5 mass percent, Mo of 0.3 to 1.0 mass percent, and O of not more than 0.0012 mass percent, in a range where (Si+Mo)≧1.0 mass percent is satisfied, and containing iron and inevitable impurities as remnants; the maximum size of oxide nonmetallic inclusions is not more than 12.5 μm when an examined area is 320 mm 2 ; the number of the oxide nonmetallic inclusions having a diameter of equivalent circle of 3 μm or more is not more than 250 when the examined area is 320 mm 2 ; and a C density of an outer layer is adjusted in a range from 0.7 to 1.2 mass percent by carburization.