Effect of pulse current on the annealing structure and property of spherical graphite iron

The effects of pulse current on the mechanical properties of spherical graphite iron, the graphitization of cementite and the transformation of ferrite were studied during the high-temperature graphitization of spherical graphite iron with pulse electric current as an assistant way. The results show that the tensile strength and the hardness of the specimen decrease, while the elongation increase. SEM micrographs of the specimen show that electropulsing promotes greatly the high-temperature graphitization of spherical graphite iron and the transformation of ferrite. The acceleration of cementite decomposition and the transformation of ferrite result from the increase of graphite nucleation rate by electropulsing.