JPS55152104A - Manufacture of powder hot forged part - Google Patents

Abstract

PURPOSE: To economically produce a powder hot forged parts having excellent mechanical properties by the steps of removing and reducing graphite content upon pulverizing a spheroidol graphite cast iron, then heating and cooling it in predetermined temperature range, forging it in a die and then diffusion sintering the cast iron.

CONSTITUTION: After the cutting chips of a spheroidal graphite cast iron are finely pulverized by a high speed hammer mill, the graphite-containing fine particles are partly removed by a cyclone to produce an iron powder containing 1.0W2.0% of C, 2W3% of Si and 0.2W0.9% of Mn with 60 mesh or less. This iron powder is press molded in a short strip or the like to produce a molded article having a density of 80W85% of base metal cast iron. A hot forging lubricant is coated on the surface of the cast iron, and the cast iron is heated at the melting point of the base metal to 1,300°C in a reducing atmosphere for 2W15 minutes. After the iron is so cooled then that the surface temperature may become 900W1,150°C, it is forged in a die to form it to a density of 100W110% of the base metal specific gravity. The iron is then heated at higher than the austenitizing temperature in the die to diffuse and sinter it. Thus, a powder hot forged parts having excellent properties can be produced by inexpensive stock material.

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