Solidification Simulation with Consideration of Local Variation of Heat Transfer Coefficient Caused by Air-gap Generation

A FEM solidification simulation software taking into consideration the local variation of the heat transfer coefficient caused by air-gap generation has been developed. This software is based on the coupling between heat propagation analysis with latent heat generation and structural analysis using the thermo-elastoplastic constitutive law. The heat transfer coefficient between the cast and mold is updated at each time increment as a function of the c1earance that occurs when the cast is shrinking. The formula for evaluating the heat transfer coefficient as a function of the c1earance has been verified by comparison with experimental data. The result obtained shows that the local variation of the heat transfer coefficient caused by air-gap generation has a significant influence on both temperature history and distribution and solidification time.