A numerical study on the effect of air gap on the solidification of A356 alloy

Among the numerous methods available to evaluate the heat transfer coefficient within the mold/casting interface, the air gap measurement and reverse-simulation methods are more common because of their simplicity and accuracy. In this research, the heat transfer coefficient at the interface between a low-carbon steel mold and A356 aluminum casting was evaluated using the reverse-simulation method. The temperature was measured in two different points of the mold in order to assess the heat transfer coefficient at the interface. The cooling curves of A356 aluminum alloy at two different superheat temperatures within the steel mold were obtained by means of a thermal analysis system. Mathematical simulation was performed using a FORTRAN code assuming complete transfer of heat from the mold wall and geometrical symmetry of the air gap, and the cooling curve information was obtained from the program. Considering the differences between the temperatures obtained from the two methods, the heat transfer coefficient at the mold wall was modified at each time interval to make the data from simulation approach the experimental data.

Keywords:

heat transfer coefficient , A356 aluminum , simulation , low carbon steel mold