Iron-based mixed powder used for powder metallurgy

Abstract

PROBLEM TO BE SOLVED: To provide iron-base mixed powder for powder metallurgy, improved in compaction density of a green compact, and at the same time significantly reduced in ejection force after the powder is compacted, by enhancing a flowability of the iron-base mixed powder using low alloy steel powder containing Mo and Mn, and thereby improved in density and strength of a sintered boy and reduced in a manufacturing cost. SOLUTION: In the iron-base mixed powder for powder metallurgy, containing iron-base powder as a main component, water atomized alloy steel powder including, as spare alloys, 0.3-1.0 mass% Mo and 0.1-0.25 mass% Mn in ratios to the entire iron-base mixed powder, and consisting of the balance Fe and inevitable impurities, is used as the iron-based powder. In the ratio to the entire iron-based mixed powder, 0.5-4.0 mass% Cu power, and 03-1.0 mass% graphite powder are contained in the iron-base mixed powder, and a flaky powder having a 100 μm or shorter average particle diameter in long diameters, a 10 μm or less thickness, and a 5 or more aspect ratio (the ratio of the long diameter to the thickness), is also added thereto in the range of 0.01-5.0 mass%.

Description

technical field [0001] The present invention relates to an iron-based mixed powder suitable for powder metallurgy technology, and in particular to an iron-based mixed powder used to increase the density of compacted powder and reduce the pull-out force when the compact is pulled out from the mold after compacting to achieve an effective increase in sintering The body density and strength of the iron-based mixed powder. Background technique [0002] As far as the powder metallurgy process is concerned, after mixing the raw material powders, the mixed powders are transported and filled into a mold for press molding, and then the manufactured molded body (called compact) is taken out of the mold and sintered as required Wait for post processing. [0003] In the above-mentioned powder metallurgy process, in order to improve product quality and reduce manufacturing costs, it is necessary to simultaneously achieve: high fluidity of the powder in the transportation process, high c...

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Problems solved by technology

However, although the steel powder obtained by this method has excellent compressibility, it has the following problems: since the diffusion of alloying elements, especially Ni, is slow, in order to sufficiently diffuse the alloying elements in the iron matrix, a long time must be carried out. sintering

[0015] However, low-alloy steel powder containing Mo and Mn is difficult to increase the density during molding due to the solid solution hardening of these elements, and in order to obtain the desired strength, molding must be performed under high pressure, so there is a problem that the life of the die is shortened.

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