A Method of Magnesium Treatment for Producing Gravity-diecast Ductile Iron

Equipment for the in-stream treatment of ductile iron has been adapted for gravity-diecasting. The treatment unit consists of a pouring basin, reaction chamber, and a reservoir for holding treated iron. The device is highly mobile in so much that it can be transferred from furnace to successive dies and back again, allowing consecutive pouring. The authors have studied the effect of reaction chamber design and nodularising-alloy type on the microstructure of cast specimens, using three types of chamber design and three types of nodulariser at different temperatures. The results indicate that a carbide-free structure with a high nodule count of up to 1500 n/mm² within the as-cast structure of a diecast rod specimen of 30 mm dia. can be achieved using this treatment equipment, when employing suitable nodularising alloy and process chamber design.