Numerical simulation of mold filling and solidification of TiAl base alloy exhaust valve in vertical centrifugal casting process

Based on N-S function, continuity function, function of Fourier heat conduction and experiments, a mathematical model of mold filling and solidification in vertical centrifugal casting is presented by taking centrifugal force, gravity and Coriolis force into consideration. This model is further applied to numerical simulation of temperature field, flow field and pressure field of vertical centrifugal casting process of exhaust valve made of TiAl base alloy. The result of numerical simulation shows that the mold filling of vertical centrifugal casting consists of forward-direction filling and back-direction filling. Gas-holes defect easily appears at the entrance of valve. The two orders also exist in solidification proces and are major reason for formation of off axis shrinkage nearby the side of filling first.