Laser surface hardening of ductile cast iron for vehicle die

Experiments of laser transformation hardening were performed with various process parameters on the surface of ductile cast iron block, which is often used for vehicle body. The distribution of microhardness along the case depth direction and the variation of microstructure of hardened track were investigated. Wear test was carried out using a ball-on-flat-type wear-test machine. The results indicate that the hardened layers after the laser surface hardening treatment have excellence wear resistance. It is seen that the surface hardness of ductile cast iron blocks increases greatly at suitable values of process parameters in laser transformation hardening, which satisfies the vehicle dies.