Iron based powder for powder metallurgy

Abstract

An iron-based mixed powder for powder metallurgy, the powder is composed of pulverized iron powder adhered to the surface by partially alloying copper powder and preferably pulverized pure iron powder, at least graphite powder and free A lubricant for fixing graphite powder and machinability-improving powder on the surface of an iron-based powder with a binder, the iron-based powder having a particle size distribution of 18.5% by mass of particles having a particle diameter of less than 45 μm relative to the total amount of the iron-based powder Less than 46% by mass of particles with a particle size of 75 μm or more and less than 150 μm; less than 10% by mass of particles with a particle size of 150 μm or more and less than 180 μm; 0.5% by mass of particles with a particle size of 180 μm or more. By making such a powder, it is possible to obtain an iron-based powder mixed powder for powder metallurgy with good compressibility and good filling properties.

Description

technical field

[0001] The invention relates to an iron-based powder mixed powder for powder metallurgy, in particular to improving the filling property of the iron-based powder mixed powder to a metal mold. Background technique

[0002] Generally, the iron-based powder mixed powder for powder metallurgy (hereinafter also referred to as iron-based mixed powder) is mixed with copper powder, graphite powder, iron phosphide powder and other alloy powders in the iron-based powder as the matrix; stearic acid Lubricants such as zinc; and machinability improvement powder added as needed. However, the iron-based mixed powder contains various powders that differ in size, shape and density. For this reason, when conveying after mixing, loading or unloading into a hopper, filling into a metal mold, and press molding, etc., the particles in the mixed powder are unevenly distributed, and segregation is likely to occur in particle size, shape, and chemical composition.

[0003] For exam...

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