IRON POWDER FOR POWDER METALLURGY, PROCESS FOR PRODUCING THE SAME, AND IRON-BASE POWDER MIXTURE FOR POWDER METALLURGY

摘要

An object of the present invention is to provide iron powders for powder metallurgy and iron base mixed powders capable of producing sintered bodies excellent in machinability and abrasion resistance. Such an object is solved in accordance with the following means.;There is provided an iron powder comprising 0.03-0.3 wt% of B, not larger than 0.07 wt% of Cr, less than 0.3 wt% of Mn, and a balance being Fe and inevitable impurities, and an intensity ratio of B to Fe as to an emission spectrum obtained through a measurement on a surface of the iron powder according to Auger electron spectroscopy is not less than 0.05. The use of this iron powder causes an amount of residual graphite in sintered bodies to increase thereby improving machinability and abrasion resistance of the sintered bodies. Further, there is provided an iron powder which comprises S, Se, Te and/or Mo in addition to the above-mentioned compositions. Furthermore, there is developed a so-called iron base mixed powder in which MoO3 powder and/or WO3 powder are mixed with said iron powders. These iron powders are produced in such a manner that in addition to the above-mentioned compositions, particularly, an amount of oxygen in a molten steel is controlled to be not more than 100 ppm, and the molten steel is water-atomized.