| 摘要 |
A carburized component with improved fatigue strength has a base steel containing, by mass %, C: 0.15-0.25%, Si: 0.03-0.50%, Mn: more than 0.60% and not more than 1.5%, P≦̸0.015%, S: 0.006-0.030%, Cr: 0.05-2.0%, Al≦̸0.10%, N≦̸0.03%, and O≦̸0.0020%, and optionally at least one element selected from Mo, Cu, Ni, B, Ti, Nb and V, the balance being Fe and impurities. A surface hardened layer portion satisfies: (a) average carbon concentration in the region from the outermost surface to a point of 0.2 mm depth of 0.35-0.60 mass %, (b) surface roughness Rz≦̸15 μm, and (c) &sgr;r(0)≦̸-800 MPa, &sgr;r(100)≦̸-800 MPa, and residual stress intensity index Ir≦̸80000, wherein Ir is calculated by [Ir=∫|&sgr;r(y)|dy], where y μm is the depth from the outermost surface and &sgr;r(y) is the residual stress for the points from the outermost surface to a depth of 100 μm with the range of y from 0 to 100 (μm). |
