Effect of copper on elastic modulus of as-cast ductile iron

In order to improve the elastic modulus of ductile iron used for machine tool, Y blocks with different copper content (0-1.1%) were prepared by using resin sand casting process. The influence of copper on microstructure and elastic modulus of as-cast ductile iron was investigated by tensile test, hardness test, metallographic microscopy and scanning electron microscopy(SEM) analysis. The results indicate that the elastic modulus of ductile iron with different content of Cu is 164-177 GPa. With increasing copper content, the elastic modulus increases, then keeps stable. Ductile iron with 0.9% Cu has the highest elastic modulus (176.7 GPa) comparing with others. Copper elements affect elastic modulus of ductile iron mainly through affecting the pearlite. Copper can significantly promote pearlite forming and decrease pearlite lamellar distance, which benefits for improving the elastic modulus of ductile iron. The ductile iron with 0.5%-0.9%Cu has good spheroidizing effect, and the pearlite content, tensile strength, hardness and the elastic modulus of the ductile iron are high. The mechanical properties meet the requirements of QT600-3.