Determination of interfacial heat-transfer boundary conditions in an aluminum low-pressure permanent mold test casting

Abstract

Great advances in casting modeling/simulation software have been made in the past several years. However, software predictions are only as accurate as the material and processing properties used as inputs. The process of low-pressure semipermanent mold casting is widely used by the automotive industry in the production of aluminum cylinder head castings. However, the process is highly sensitive to various casting parameters and many of the influences are not well understood. This report presents results from casting experiments and simulations using a specially designed casting, the “wing casting.” The casting experiments demonstrated the variation in temperature change in different parts of the casting for different processing parameters. Boundary conditions were determined for different areas on the mold surface and those parameters were discussed in terms of temperature sensitivity in the casting behavior. It was also demonstrated that boundary conditions play a major role in the thermal behavior in the casting during solidification. Finally, changes in the mold/casting surface geometry were found to have a large influence on the value of the boundary conditions.