CARBURIZED COMPONENT EXCELLENT IN LOW-CYCLE IMPACT FATIGUE RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide a carburized component having an excellent durability against failure caused by low-cycle impact fatigue.;SOLUTION: The carburized component is made of steel material comprising specific amounts of C, Si, Mn, P, S, Cr, Al, Ti, B, N, Nb and V and the balance being Fe and impurities, wherein Mo+Cr+(Ni/2)-(Si/5)-P^0.5+{B/(Ti-3.4N)} is 1.2 and C^0.8+(Mn/20)^1.25+(Cr/6)^0.85+(Mo/5)^0.74+B^0.21 is ≥0.8. The square root RS of a maximum area of MnS is ≤40 μm when cumulative distribution function, predicted by applying extreme value statistics to the square root of the area of a plane of MnS formed by cutting the component in a manner parallel to rolling direction or forging axis of its material, is 99%. The C concentration at the surface of a carburized layer is ≤0.85 mass%.;COPYRIGHT: (C)2004,JPO&NCIPI