PROCESS FOR PRODUCING ANNULAR PART.

摘要

A process for producing an annular part excellent in abrasion resistance and mechanical strength, wherein the surface layer of which an abrasion resistance is required has a hardness of HRC (58 to 63) and the inside has a hardness of HRC (25 to 40), said process comprising subjecting a powdery raw material composed of 0.4 to 0.9 wt.% of carbon 1.5 to 4.0 wt.% of nickel, 0.2 to 0.6 wt.% of molybdenum, and the balance of iron and inevitable impurities to compression molding, sintering, forging, hardening at a temperature ranging from 800 to 950 DEG C, high-temperature tempering at a temperature ranging from 570 to 700 DEG C for 20 to 60 min, hardening of the surface layer(s) of the inner and/or outer periphery of the sinter, and if necessary low-temperature tempering at a temperature ranging from 160 to 220 DEG C.