Abstract: In this paper, the FEM is used to simulate the solidification of a casting which contains internal chills. The unstable phenominon in the calculation of FEM is discussed by means of numerical analysis. The equivalent initial temperature method is proposed to simulate the effect of the internal chill, the difference of temperature is used to simulate the effect of the heat resistance of the casting-chill interface. Finally, both numerical simulation and the practical test on the solidification of a cast steel gear are carried out in the First Heavy Machine Plant, and the casting technique of the gear is analysed in detail.

Key words: 内冷铁, 有限元, 铸件凝固