Abstract: A high surface-pressure resistant component includes a steel having a composition containing, in mass %, 0.17-0.23% of C, 0.80-1.00% of Si, 0.65-1.00% of Mn, 0.030% or less of P, 0.030% or less of S, 0.01-1.00% of Cu, 0.01-3.00% of Ni, and 0.80-1.00% of Cr, with the remainder being Fe and unavoidable impurities, in which the surface layer C concentration of a carburized and quenched layer is 0.70-0.80% in mass %.

Abstract: A nitrocarburized crankshaft member made of a steel having essentially ferrite and perlite, and at least a portion of a steel surface thereof having a ferrite surface area of 50% or greater that is imparted with a nitrocarburized hard layer. The steel consists of C, Si, Mn, Cu, Ni, and Cr as required elements and Mo, N, s-Al, Ti, Pb, Bi, and Ca as optional elements that may be included, and Fe and inevitable impurities. C is within a range of 0.25 to 0.32%. The nitrocarburized crankshaft member includes a thickness of a surface compound layer of the nitrocarburized hard layer of 10 to 35 ?m that is formed during establishment of a diffusion depth of a nitrogen diffusion zone below the surface compound layer of 700 ?m or greater.

Abstract: A nitrocarburized crankshaft member made of a steel that includes C in an amount by weight of 0.25 to 0.32% as a required element and an optional element that may be included, and Fe and inevitable impurities in a remaining portion. The steel-made crankshaft member mainly includes ferrite and perlite, wherein at least a portion of the steel surface thereof having a ferrite surface area of 50% or greater is imparted with a nitrocarburized hard layer. The nitrocarburized hard layer includes a surface compound layer suppressed to a thickness of 10 to 35 ?m, and a nitrogen diffusion zone below the surface compound layer having a diffusion depth of 700 ?m or greater. The steel includes C, Si, Mn, Cu, Ni, and Cr as the required elements and Mo, N, s-Al, and Ti as the optional elements.

Abstract: The invention relates to a crankshaft member having high fatigue strength and good bending correctability, and its method of manufacture. The steel made crankshaft member mainly consists of a two-phase structure of ferrite and perlite. The steel includes C, Ni, Mn, and Cr as required elements and Si, Cu, Mo, Ti, V, Nb, Ca, and S as optional elements that may be included, in the amounts of C within the range of 0.20 to 0.50 wt %, Si within the range of 0 to 0.6 wt %, Mn within the range of 0.5 to 1.5 wt %, Cu within the range of 0 to 0.7 wt %, Ni within the range of 0.05 to 1.5 wt %, Cr within the range of 0.05 to 0.45 wt %, and Mo within the range of 0 to 0.5 wt % to satisfy the condition 115?70C+8Si+23Mn+11Cu+128Cr+83Mo?50. A portion of the member surface is provided at least with a hard nitride layer having an average hardness within the range of 300 to 450 HV. Lamellar spacing of the perlite is 0.3 ?m or less.

Abstract: A nitrocarburized crankshaft member made of a steel that includes C in an amount by weight of 0.25 to 0.32% as a required element and an optional element that may be included, and Fe and inevitable impurities in a remaining portion. The steel-made crankshaft member mainly includes ferrite and perlite, wherein at least a portion of the steel surface thereof having a ferrite surface area of 50% or greater is imparted with a nitrocarburized hard layer. The nitrocarburized hard layer includes a surface compound layer suppressed to a thickness of 10 to 35 ?m, and a nitrogen diffusion zone below the surface compound layer having a diffusion depth of 700 ?m or greater. The steel includes C, Si, Mn, Cu, Ni, and Cr as the required elements and Mo, N, s-Al, and Ti as the optional elements.

Abstract: The invention relates to a crankshaft member having high fatigue strength and good bending correctability, and its method of manufacture. The steel made crankshaft member mainly consists of a two-phase structure of ferrite and perlite. The steel includes C, Ni, Mn, and Cr as required elements and Si, Cu, Mo, Ti, V, Nb, Ca, and S as optional elements that may be included, in the amounts of C within the range of 0.20 to 0.50 wt %, Si within the range of 0 to 0.6 wt %, Mn within the range of 0.5 to 1.5 wt %, Cu within the range of 0 to 0.7 wt %, Ni within the range of 0.05 to 1.5 wt %, Cr within the range of 0.05 to 0.45 wt %, and Mo within the range of 0 to 0.5 wt % to satisfy the condition 115?70 C+8 Si+23 Mn+11 Cu+128 Cr+83 Mo?50. A portion of the member surface is provided at least with a hard nitride layer having an average hardness within the range of 300 to 450 HV. Lamellar spacing of the perlite is 0.3 ?m or less.