PURPOSE: To obtain the sintered body of the high-alloy tool steel which is free from structural defects in material, such as formation of coarse crystal grains, formation of macrocarbides arising from the melting and aggregating of carbides, and is free from material defects, such as holes, after sintering.
CONSTITUTION: Fine particles of the high-alloy tool steel having the grain sizes ranging from <101 up to 10-2μm are incorporated at 20 to 80% into 80 to 20wt.% coarse particles of the high-alloy tool steel having 101 to <103μm grain sizes, by which a dense characteristic of 100% relative density is obtd. Further, the above-mentioned powder is compacted and molded and the molding is subjected to a solid phase sintering treatment for about 120 minutes at 1503 to 1573K temp. in a vacuum atmosphere.
KARAKI MICHIO
YAMAZUMI UMIMORI
NACHI FUJIKOSHI CORP