Development of Functional Iron Powder Premixes

Improvement of the functions of iron powder premixes for easy use and high performance was studied from the viewpoints of both the lubricant used and the iron powder itself. From the viewpoint of lubricants, the characteristics realized included (1) improved flowability of wax lubricant type premixes by controlling the adhesive force between powder particles and (2) improved compressibility of premixes for warm compaction by promoting powder rearrangement during compacting. Characteristics realized by improvement of the iron powder itself included (3) stabilized dimensional change during sintering of Fe-Cu-C system sintered materials by controlling the Si content of the iron powder, (4) high tensile strength of 1000MPa without heat treatment by forming a fine pearlite microstructure using 1Cr-0.3Mo-0.3V (mass%) completely alloyed steel powder, and (5) improved machinability with a 40% decrease in tool wear without heat treatment using 2Ni-1Mo partially alloyed steel powder, while securing the same strength as conventional 4Ni-1.5Cu-0.5Mo partially alloyed steel powder after heat treatment.