Development of semi-solid ductile cast iron

Abstract

Semi-solid metal casting and forming is a promising process for production of a wide range of metal alloys. In spite of the growing application of semi-solid processed light alloys, little research has been reported on semi-solid processing of iron and steel. In this study, inclined plate and stirring processes were used to change the dendritic structure of iron to globular structure. The effect of stirring time and speed, length and slope of plate on the casting structure was examined. The results show that both processes can effectively change the dendritic structure to globular. Optimum graphite nodularity and solid particle globularity were achieved following mechanical stirring at 150 rev min-1 for 9 min with a cooling rate of 0.25 K s-1 (15°C min-1) and with a slope plate angle of 7.5° and length of 560 mm with cooling rate of 67 K s-1. In addition, the results show that inoculant fading can be prevented more easily using a slope plate, since the total process time is short.