Effects of reduced pressure and casting design on mold filling in expendable pattern casting process of thin wall aluminum alloy castings

Abstract

The effects of reduced pressure and casting design on mold filling for thin wall aluminum alloy castings in the expendable pattern casting (EPC) process were investigated experimentally. Thin wall aluminum alloy plates were cast by the EPC process using several coats with different permeabilities. The fluidity length and melt velocity were measured. The application of the reduced pressure condition in the flask led to a larger melt velocity and longer melt fluidity length. There was no significant difference in the melt velocity depending on the casting design. However in the high coat permeability region, the melt fluidity length in top pouring was longer than that in bottom pouring. The distances of melt flow stop were predicted based on the heat transfer from the molten metal to the mold through the coat using measured melt velocities. Except with top pouring in the high coat permeability region, the predicted values more or less agreed with experimental fluidity length values.