Effect of Slope Plate Variable and Reheating on the Semi-Solid Structure of Ductile Cast Iron

Semi-solid metal casting and forming is a promising production method for a wide range of metal alloys. In spite of many applications for semi-solid processed light alloys, few works have reported on the semi-solid processing of iron and steel. In this research, an inclined plate was used to change the dendritic structure of iron to globular. The effects of the length and slope of the plate on the casting structure were examined. The results show that the process effectively changes the dendritic structure to globular. A sloped plate angle of 7.5° and length of 560 mm with a cooling rate of 67 K · s^-1 gave the optimum graphite nodularity and solid particle globularity. The results also show that the sloped plate more easily prevents inoculant fading since the total time processing is rather short. In addition the semi-solid ductile cast iron prepared using the inclined plate method was reheated to examine the effect of reheating conditions on the microstructure and coarsening kinetics of the alloy. The solid fractions at different reheating temperatures and holding times were used to find the optimum reheating temperature range.