Kawasaki Steel Corporation

Unisia Jecs Corporation

Other

Hiroyuki Amma

Takashi Yoshimura

Masashi Fujinaga

Satoshi Uenosono

Shigeru Unami

Takayuki Matsumoto

Mitsumasa Iijima

Yasuo Hatai

In a preliminary molding step, a metallic powder mixtureobtained by blending an iron-based metal powderwith graphitesuch that the graphite is present in an amount of preferably not less than 0.1% by weight, more preferably not less than 0.3% by weight, is compacted into a preformhaving a density of not less than 7.3 g/cm. In a provisional sintering step, the preformis provisionally sintered at a predetermined temperature to form a metallic powder-molded bodyhaving a structure in which the graphite remains along a grain boundary of the metal powder. In a re-compaction step, the metallic powder-molded bodyis re-compacted into a re-compacted body. In a re-sintering step, the re-compacted bodyis re-sintered to obtain a sintered body. In a heat treatment step, the sintered bodyis heat-treated to obtain a heat-treated sintered body Accordingly, in accordance with the present invention, there are provided a re-compacted body produced from a metallic powder-molded body having an excellent deformability which is suitably applied to the production of machine parts exhibiting high mechanical properties due to the use of sintered metal, and a sintered body produced from the re-compacted body as well as a process for the production thereof.

Metallic powder-molded body, re-compacted body of the molded body, sintered body produced from the re-compacted body, and processes for production thereof

Metallic powder molding material and its re-compression molded body and sintered body obtained from the re-compression molded body and production methods thereof

Sintered powder metal bodies and process for producing the same

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Yokohama, Japan

Hiroyuki Amma