Halide treatment for aluminum lost foam casting process

摘要

Casting aluminum by a lost foam process is improved by treating the metal during pattern replacement with a halide salt flux to inhibit formation of oxide fold defects. A preferred flux comprises a mixture of alkaline metal chloride compounds and includes an aluminum fluoride salt, such as sodium aluminum fluoride. In a preferred embodiment, the flux is incorporated into a polystyrene pattern prior to embedding the pattern in a sand mold and becomes dispersed on a front of the cast metal as the front progressively decomposes the pattern.