METHOD FOR PRODUCING MIXED POWDER FOR POWDER METALLURGY, METHOD FOR PRODUCING SINTERED COMPACT, AND SINTERED COMPACT

摘要

Provided is a mixed powder for powder metallurgy with which it is possible to obtain a sintered compact that, despite not containing Ni, has an excellent tensile strength and ductility equivalent to or better than those of a sintered compact containing Ni. This method for producing a mixed powder for powder metallurgy includes: a first mixing step, in which a starting material mixed powder is obtained by mixing a Mo-containing powder and a Cu-containing powder into an iron-based powder; a diffusion/adhering step, in which a partially-diffused alloyed steel powder is obtained by diffusing and adhering the Mo and Cu onto the surface of the iron-based powder by heat-treating the starting material mixed powder; and a second mixing step, in which the mixed powder for powder metallurgy is obtained by mixing a graphite powder into the partially-diffused alloyed steel powder. The average grain diameter of the iron-based powder is 30-120 μm. A cuprous oxide powder is used as the Cu-containing powder. The component composition of the mixed powder for powder metallurgy is 0.2-1.5 mass% Mo, 0.5-4.0 mass% Cu, and 0.1-1.0 mass% C, with the remainder comprising Fe and unavoidable impurities.