| 摘要 |
PROBLEM TO BE SOLVED: To provide an iron-based powdery mixture for powder metallurgy having excellent compressibility and also having excellent packing properties. SOLUTION: The iron-based powdery mixture comprises: iron-based powder composed of atomized pure iron powder and atomized iron powder, preferably, to which copper powder with a grain size of 20 to 100μm is partially diffused and stuck to the surface; and graphite powder; or further, powder for improving machinability; and further, a free lubricant, and the graphite powder and the powder for improving machinability are fixed to the surface of the iron-based powder with a binder. thus its apparent density is controlled to≥3.1 Mg/m<SP>3</SP>. The iron-based powder has a grain size distribution at least comprising, to the total amount of the iron-based powder, grains with a grain size of <45μm in≤18.5 mass%, grains with a grain size of 75 to <150μm in≥46 mass%, grains with a grain size of 150 to <180μm in <10 mass%, and grains with a grain size of≥180μm in≤0.5 mass%. Further, the graphite powder is fixed to the surface of the iron-based powder preferably in such a manner that the sticking ratio is controlled to≥85%. COPYRIGHT: (C)2005,JPO&NCIPI
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