| 摘要 |
PROBLEM TO BE SOLVED: To improve the wear resistance which is required for the elongation of the service life of a high strength machine component while sufficiently securing toughness, with respect to a steel member composed of a hypoeutectoid steel. SOLUTION: The stock steel sheet for a machine component has a chemical composition containing, by mass%, 0.32 to 0.70%, preferably, >0.45 to 0.70% C,≤0.5% Si, 0.1 to 1.5% Mn,≤0.03% P,≤0.02% S and 0.1 to 0.5% Nb, and if required, further <0.1% Ti, and, if required, further one or more kinds selected from≤1.5% Cr,≤0.5% Mo,≤0.5% V,≤2% Ni and 0.005% B, and the balance Fe with inevitable impurities, and has an annealed structure where carbides with grain sizes of≥1μm containing Nb are present in a matrix with density of 200 to 1,000 pieces/mm<SP>2</SP>. By subjecting the stock to quenching and tempering treatment, the steel member having excellent wear resistance and toughness is obtained. COPYRIGHT: (C)2010,JPO&INPIT |
