Study on Preparation and Microstructure of As-cast QT550-7 Ductile Iron

In order to study the microstructure of as-cast QT550-7 ductile iron,solidification processes of the molten iron and mechanism of graphite spheroidization,some ductile iron samples were prepared by the duplex melting method using the material such as returns,pig iron,steel scrap,nodularizing alloys,inoculants and so on.The composition and the mechanical properties of the materials can meet the need of the QT550-7 ductile iron after the testing.The microstructure was composed of ferrite,pearlite and spheroidal graphite.The solidification processes was mushy freezing.