Patent ID: 9732407
Date: 2017-08-15
CPC Classifications: B22D,C21C,C21D,C22C,F16C

Claim:
1. A bearing steel comprising, as a chemical composition, by mass %, C: 0.9% to 1.5%, Si: 0.1% to 0.8%, Mn: 0.1% to 1.5%, Cr: 0.5% to 2.0%, Al: 0.01% to 0.05%, Ca: 0.00001% to 0.0050%, Rare Earth Metal: 0.0001% to 0.050%, O: 0.0001% to 0.0030%, Ti: limited to less than 0.005%, N: limited to 0.015% or less, P: limited to 0.03% or less, S: limited to 0.05% or less, and a balance consisting of iron and unavoidable impurities, and comprising, as a metallographic structure, inclusions which contain complex oxysulfides including Rare Earth Metal, Ca, O, S, and Al, TiN, MnS, Al wherein, a number fraction of the complex oxysulfides in a total number of the inclusions is 50% to less than 100% and a number of complex oxysulfides having a major axis of 5 μm or more is 0.001 pieces to 2 pieces in an observed section of 1 mm a number of TiN existing independently from the complex oxysulfides and having a major axis of 5 μm or more is 0.001 pieces to less than 1.0 piece in the observed section of 1 mm