Microstructure and strength of Fe-2%Cu-0.8%C sintered steel using Fe-Cu alloy powder

Both copper wires and ferrous chassis are included in automotive scrap. Copper can directly influence the mechanical properties of steel products, and is generally considered to be a harmful tramp element. In contrast, copper is actively used for various sintered machine parts, because the Fe-Cu-C type can combine performance and economical efficiency, and does not require the advanced technique. Thus, a study was conducted utilizing powder metallurgy and Fe-Cu alloy powder to determine the possibility of using the rational processing of recycling copper-rich scrap. The microstructure and strength of the Fe-2%Cu-0.8%C compacts sintered with Fe-Cu alloy powder, were considerably influenced by the Fe/Fe-Cu powder mass ratio. The weight change decreased with the increase in the Fe/Fe-Cu powder mass ratio. This shows that graphite was consumed to reduce the reaction of oxide film on the Fe-Cu alloy powder surface. The strength of sintered compacts increased as the Fe/Fe-Cu powder mass ratio increased. For example, when Fe-Cu alloy powder is used in conjunction with an oxide film, the desirable Fe/Fe-Cu powder mass ratio is more than 3 in order to obtain a sintered compact with transverse rupture strength higher than 700 MPa.