| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide high strength steel components for machine structure which are quench heat-treated by carburizing, nitriding, etc., and in which the additive quantities of expensive hardenability-improving elements, such as Cr, Mo and Ni, can be minimized and hereby excellent workability can be provided in a state before heat treatment and excellent fatigue characteristics can be exhibited after quenching/tempering. <P>SOLUTION: The high strength steel component for machine structure with excellent fatigue characteristics has a composition in which respective contents of C, Si, Mn, B, N, etc., are specified and at least one element selected from the group consisting of Nb, Ti, Zr, Ta and Hf is contained within the range satisfying the relation in inequality SM≥1.0×10<SP>-5</SP>(where SM satisfies equation SM=[Nb]/92.9+[Ti]/47.9+[Zr]/91.2+[Ta]/181+[Hf]/178). In the above equation, [Nb], [Ti], [Zr], [Ta] and [Hf] represent their respective amounts (mass%) in the form of solid solution which are measured from the respective extraction residues of the elements contained in the steel parts. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
