Modelling the heat transfer coefficient at the cast/chill interface to account for the effect of metal head

The evolution of heat transfer coefficient (HTC) in the sand casting of A357 aluminum alloy against aluminum chills is evaluated with different metal heads in order to study the effect of pressure on the HTC. Inverse modeling techniques based on Beck’s analysis were used to determine the experimental evolution of HTC as a function of time, casting temperature and chill temperature. The experiments were reconstructed by means of numerical analyses in order to determine the best way to fit the experimental data. Two approaches were considered: in the first, a simple thermal analysis of the solidification was carried out with the HTC depending on both the interface casting temperature and the effective metal head as they were determined from the experiments; in the second, a coupled thermal-stress analysis was performed, with the HTC dependent on the interface pressure.