PURPOSE: To obtain a sintered member having high dimensional accuracy and density by premolding under pressure the iron (alloy) molding which is premolded under pressure, and cooling the molding after heating in a nonoxidative atmosphere the subjecting the cooled molding to a zinc phosphate and zinc stearate teatment, molding the treated molding by compression and further sintering the same in a nonoxidative atmosphere.

CONSTITUTION: Powder of iron or a powder mixture consisting essentially of powder of iron or an iron alloy is premolded under 4W8tons/cm2 pressure. The preferable content of the iron in the powder mixture is ≥70wt%. After the premolding is heated at 500W1,000°C in a nonoxidative atmosphere, the molding is cooled in a furnce and is subjected to stress relieving and softening. The cooling is accomplished at 3,000°C/hour. The annealed premolding is subjected to a zinc phosphate treatment whereby a zinc phosphate film is formed thereon. In succession, the molding is treated with sodium stearate, whereby a zinc stearate film is formed thereon. The premolding formed with such films is molded by compression under 8W18tons/cm2 pressure in hermetic molding dies; thereafter the molding is sintered in a nonoxidative atmosphere, whereby the intended sintered member of high density is obtained.