Abstract
The disused car scrap with the copper wire etc. is crushed together, and dissolved in an electric furnace. The removal of copper from the steel scrap that is thus inevitably contained high copper is difficult. Because the copper causes surface hot-shortness during hot rolling of steel, it is usually considered as a harmful tramp element. In powder metallurgy, the processing of recycling copper rich scrap was studied. Although the obtained materials showed high strength, this processing is not cost-effective for high-volume production.
Therefore, we focused on the conventional compacting-sintering in order to recycle high-copper steel scrap efficiently. The mixture of gas-atomized Fe-4mass%Cu powder, pure iron powder and graphite was compacted with the die wall lubricating method. The obtained green compacts were sintered at 1423 K for 1.8 ks in an argon atmosphere. The transverse rupture strength and sintered density were 500 MPa and 7.0 Mg/m3 respectively though the pearlite was hardly observed compared with standard Fe-Cu-C type sintered materials. Thus there is still room for improvement in strength property of the alloyed powder mixture obtained from the conventional process. In conclusion, the possibility of high-copper scrap recycling using conventional powder metallurgy was found.
