Patent ID: 7207933
Filing Date: 2007-04-24
Classification: C21D,C23C,F01L,F16C,Y10S,Y10T

Abstract:
1. A roller member comprising: high carbon chromium bearing steel having a carburization treatment, said bearing steel comprising: a surface portion defined as a range between a surface of a rolling face of the roller member to a depth where a maximum shearing stress acts thereon, said surface portion containing carbon in a total amount comprising a range of 1.0 to 1.6 wt % and an amount of residual austenite comprising a range of 20 vol % to 35 vol %; wherein a compression residual stress of said surface portion comprises a range of 150 to 1000 MPa. wherein a surface hardness of said surface portion comprises a range of 64 or higher in Rockwell C hardness, wherein an amount of carbide precipitate an the surface portion comprises a range of 10% to 25% in an area rate and each carbide particle size comprises a range of 3 μm or less.