Study on heat transfer behaviors between Al-Mg-Si alloy and die material at different contact conditions based on inverse heat conduction algorithm

The heat transfer between Al-Mg-Si alloy and die steel during warm or hot forming process is of great influence on the temperature and stress fields of product. The interfacial heat transfer coefficient (IHTC) is also an indispensable boundary condition in the numerical simulation of warm or hot forming process, which is affected by many factors and hard to be quantified. In this study, an inverse heat conduction algorithm and new experimental apparatus were developed to determine the transient IHTC between Al-Mg-Si alloy and die steel under low contact pressure and large surface roughness. The effectiveness and feasibility of the algorithm and apparatus were verified by comparison of the calculated and measured temperatures. The influences of initial temperature of aluminum alloy, surface roughness of die steel, interfacial contact pressure and heat flux direction on the IHTC were evaluated. The results show that the calculated temperatures are in good agreement with those obtained from different measuring locations, which indicates that the inverse heat conduction method and experimental apparatus are feasible and reliable. After the samples contact with each other, the IHTC rises sharply in a short time, then slowly increases to a peak value and finally tends to decrease slightly. With the increase of the initial temperature of aluminum sample, interfacial contact pressure and the decrease of surface roughness of die steel, the IHTC increases significantly. The IHTC for the heat flux transfer from aluminum alloy to die material is obviously larger than that from die material to aluminum alloy.