A Model to Predict the Heat Transfer Coefficient at the Casting-Die Interface for the High Pressure Die Casting Process

Abstract

A model is presented for the prediction of the heat transfer coefficient (HTC) at the casting‐die interface as a function of time for the high pressure die casting process. Contact geometry and interface characteristics are included in the model through die surface roughness, the mean trapped air layer between the casting and the die, the parameters of area density and the radius of contact spots. The density and the radius of contact spots are integrated into a classical thermal flux tube theory in order to calculate HTC at the casting‐die interface. The time dependence of the HTC is derived in terms of the degradation of contact between the casting and the die that occurs during solidification. The calculated HTC is found to agree well with the experimentally determined results for different casting conditions. The presented model provides a valuable tool to predict the effect of various casting process parameters, die surface roughness, casting quality and thickness on the HTC during the high pressure die casting process.