The sand mold gravity casting process for ZL104aluminum alloy piston was simulated by the ProCAST software.Based on the simulated results

the velocity field and temperature field of filling and solidification process were predicted

and the defect area was estimated.The optimized processing design was presented.With adding a riser and reducing the casting speed

the defect position in the initial castings was transferred

and the quality and yield of the castings were improved.