| 摘要 |
PURPOSE:To obtain alloy steel powder for powder metallurgy having excellent compressibility by diffusing and sticking a powder alloy consisting of plural components to the surface of iron or steel powder and specifying the concn. of the respective alloys diffused and stuck to the iron or steel powder having a prescribed grain size. CONSTITUTION:Ni and Mo which are the alloy components to suppress and control the reaction of steel powder and C are dispersed in the form of fine metallic powder or the compd. thereof into a liquid (methyl alcohol, etc.) which does not dissolve such components. The liquid and the iron or steel powder are thoroughly mixed to stick the alloy components to the surface of the iron or steel powder than the powder is dried. The iron or steel powder is then treated in a reducing atmosphere to diffuse the Ni and Mo to the surface thereof. The concn. of the Ni and Mo diffused and stuck to the iron or steel powder having <=44mu grain size is maintained within the concn. range of 0.8-1.9 times the concn. of the Ni and Mo diffused and stuck to the entire iron or steel powder. The upper limit of the Ni is specified to 10.0wt% and the upper limit of the Mo to 0.1-0.4wt%. High toughness is obtd. if the sintered body for which such iron powder is used is subjected to a carburization treatment.
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