Shrinkage Cavities in Conical Mold Castings of Aluminum Alloy

There are casting defects caused by insufficient behaviors of heat transfer and solidification, such as a shrinkage cavity and porosity. To obtain a sound casting, the prediction of the location and size of defects using the casting CAE simulation is a useful and effective method. As the current defect prediction in casting CAE is limited to qualitative evaluation, it is necessary to predict defects quantitatively. Conical mold castings are suited for predictive verification of simulations because they are prone to shrinkage cavity defects. This study performed shrinkage evaluation experiments on aluminum alloys using a conical mold. The pipe-like internal shrinkage that occurred in the center of the casting originates from the reinstallation of the stopper, and it clarified that breaking the oxide film affects the internal shrinkage. Further, the shrinkage cavities were estimated using Eulerian and Lagrangian casting CAE software. Comparison with experimental results showed that it is difficult to match the boundary conditions in the simulations to the actual phenomena.