| 摘要 |
<p>The invention relates to a method for producing a hot forged material from powder having a particularly high frictional sliding property as well as high tensile strength, compression strength and toughness, for use in assemblies, such as a steel gear, cam, and the like, the said material comprising Si in 1.4~ 3.5%, Mn in 0.2~0.9% and C in 1.0~2.0% by weight, the remainder substantially consisting of iron, 0.2~1.2% of free carbon out of the carbon content being dispersed and precipitated as spherical graphite microparticles 0.5~10.mu.m dimension, wherein (1) swarf from a mother material of spheroidal graphite cast iron (FCD cast iron) is pulverized by impact, the graphite microparticle component being separated and removed by means of air classification whereby the carbon content of the powder body is controlled within the range of 1.0~2.5%; (2) the said powder body being preformed to a density of 80~85% of the mother material specific gravity, a lubricant for hot forging being applied thereon; (3) the said preformed body being heated for 10 seconds to 15 minutes in nondecarburizing atmosphere at a temperature above the mother material melting point and below 1300 C and then cooled until its surface temperature is 1000~1150 C. subsequently the said body being forged in a die so that its specific gravity is 100~110% of that of the mother material; (4) the forged body being subjected a diffusion treatment by heating it above the austenitizing temperature.</p> |
