There exist deformations in the punch and die chamber during squeezing casting as a result of thermal-mechanical loading effects.Injection process of the vertical squeeze casting step plate was simulated by the ProCAST software.The deformation of the punch and die chamber was presented during the eight squeeze casting cycles

and the dynamic match gap was calculated out.The result shows that the radial sizes of the punch and die chamber are increased after being heated

and the expansion of the punch is higher than that of die chamber.The gap value is decreased from the initial 0.120 0 mm to 0.029 8 mm

and the reducing margin becomes smaller and smaller.Finally

the gap value tends to be stable.