Study On The Interfacial Heat Transfer Coefficient During AZ91D Sand Casting Process

During the simulation process of sand casting solidification of AZ91Dmagnesium, the interfacial heat transfer coefficient (IHTC) betweencasting and mold or chill is one of the most important boundary condition.In the previous simulation process, it is often been taken as a constant,which leads to the inaccuracy of simulation results. Therefore, it makesgreat sense to get IHTC variation in different process condition accuratelyfor the supplement of simulation data and improvement of simulationaccuracyIn this investigation, AZ91D was chosen as casting and silica sandwas mold material, IHTC was calculated by inverse method based onmeasured temperature distribution in casting and mold or chill duringcasting solidification process. The effect of casting size as well as the chillmaterial and thickness on IHTC were researched in depth. In addition, thesame solidification process was simulated by Anycasting based on thecalculated IHTC, making comparison with the measured one.According to research result of five type of IHTC, the peak value ofIHTC increases with the casting size, which are100W/(m2K)、152W/(m2K)、204W/(m2K)、320W/(m2K)�'�525W/(m2K). In liquid-solidtemperature area of350mm system and180mm system, IHTC shows threetype of variation stage, while in the system of100mm、80mm and50mmthe similar law are not found. The temperature difference betweencalculation result of Anycasting based on calculated IHTC and measured one are between0oC to15oC, which means the feasibility of using inversemethod.The IHTC of AZ91D casting and aluminum chill with30mmthickness is higher than10mm thickness; The IHTC of AZ91D casting andcasting iron chill shows higher value with bigger thickness; The IHTC ofAZ91D casting and steel chill shows higher value with smaller thickness.