| 摘要 |
<p>PURPOSE:To produce the powder hot forged parts with low cost by compression- molding the powder of the cutting scrap reduced of carbon content by grinding the cutting scrap of cast iron and separating the graphite contained then coating lubricating material for hot forging and subjecting the molding to heating and forging. CONSTITUTION:Inexpensive cutting scrap produced by machining of FCD cast iron is pulverized by high speed hammer mills to ground the carbon content, which is then separated away by a cyclone. The resultant ground cutting scrap has the components containing Si; 2-3%, Mn; 0.2-0.9%, C; 1.0-2.5%. This powder is compression molded to the specified shape to the molding having the density of 80-85% of base material specific gravity. A lubricating agent for hot forging is coated to this, after which the molding is heated for 10 seconds to 15 minutes at the melting point of the base material to 1300 deg.C in the decarbonizing atmosphere of nitrogen gas added with hydrocarbon gas. Next, it is put in a holding furnace and is cooled to the surface temperatures of 1000-1150 deg.C, after which it is forged in dies to be made to 100-110% of the specific gravity of the base material. Furhter it is diffusion annealed at above its austenitizing temperature.</p> |
