Iron-based mixed powder used for powder metallurgy

Abstract

The invention provides an iron-based mixed powder used for powder metallurgy. By improving the flowability of iron-base powder of low alloy steel powder containing Mo and Mn, the forming density of powder can be improved and the extraction force after the powder is formed can be reduced substantially, thereby realizing the improvement of the density and strength of the sintering body and the decrease of the manufacturing cost. The iron-base powder of the iron-based mixed powder used for powder metallurgy adopts water atomizing alloy steel powder containing, by mass, Mo of 0.3 to 1.0 percent, and Mn 0.1 to 0.25 percent, as pre-alloy. The rest is iron and impurities. And Cu powder of 0.5 to 4.0 percents by mass, graphite powder of 0.3 to 1.0 percent by mass and sheet shaped powder of 0.01 to 5.0 percents by mass are added into the iron-based mixed powder. The average grain diameter of a long diameter of the sheet shaped powder is less than 100 micro meters and the thickness is less than 10 micro meters. And the draw ratio is higher than 5.

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...

AI Technical Summary

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.

Images