Two kinds of gating system for AZ91Dmagnesium alloy instrument cover were designed.Filling and solidification of the liquid magnesium alloy in the two gating systems were visualized by the ProCAST software to predict the distribution and volumetric fraction of potential defects

such as porosity

hole and gas hole

by combining with the casting velocitytime graph of selected nodes

the velocity-vector graph of the confluence of liquid metal and the distribution of solidification time

and optimized gating system was presented.The results indicate that under the conditions of 660℃ pouring temperature

200℃initial die temperature and 2.5m/s injection velocity

the gating system with ingate setting on the maximum wall thickness is more reasonable.