ZUSAMMENGESETZTES LEGIERUNGSSTAHLPULVER UND GESINTERTER LEGIERUNGSSTAHL.

摘要

PCT No. PCT/JP88/01007 Sec. 371 Date Jul. 14, 1989 Sec. 102(e) Date Jul. 14, 1989 PCT Filed Sep. 30, 1988 PCT Pub. No. WO89/02802 PCT Pub. Date Apr. 6, 1989.Provided herein are high-strength high-toughness sintered alloy steel and composite alloy steel powder useful for the production thereof. The sintered alloy steel contains, as the alloy components in the final product, Ni, Mo, and/or W, and C, if necessary, said alloy being composed of 0.50-3.50 wt % of Ni, 0.65-3.50 wt % of Mo+1/2W, (and 0.3-0.8 wt % of C, if necessary), and the remainder of Fe and inevitable impurities, and has a density higher than 7.0 g/cm3 and a tensile strength higher than 130 kgf/mm2 after quenching and tempering. The composite alloy steel powder is composed of iron powder particles and powdery alloy components attached by diffusion to part of the surface of the iron powder particles, with the content of Ni and the content of Mo+1/2W in the steel powder of particle diameter smaller than 45 INFINITY m being in the range of 2.0-4.2 times the average content in the entire steel powder. The sintered alloy steel has high strength and high toughness despites its comparatively low alloy composition and can be produced without any special equipment. The heat-treated sintered steel meets the requirements for automotive parts and the like.