Research of Feeding Effect of Ductile Cast Iron under Different Riser Conditions

Ductile cast iron has typical characteristics of mushy solidification and ductile expansion. The feeding effect of ductile cast iron was studied by means of numerical simulation and pouring tests. The prototypes used for experiments were designed into three types: riser without neck; riser with narrow neck; and riser-less. The corresponding molds were made of coated sand. The pouring temperature was set to 1350 °C, 1300 °C, and 1250 °C, separately. Results showed that the feeding effect could be controlled by the riser structure and the pouring temperature comprehensively. If the pouring temperature was higher than a certain value, the casting should be fed by a riser, and the riser structure would play an important role. However, it was very hard to design a riser exactly, and the unsuitable riser would cause macro porosity or surface sink. When the pouring temperature decreased to a certain value, there was no macro porosity or surface sink. It could provide a potential method to simplify the feeding process and improve the casting quality.