Evaluating Heat Resistance of Mold Shells in Investment Casting

Abstract

The paper describes the theory of developing the heat-resistance criterion for disposable ceramic molds exposed to poured metal, creating a computational and experimental method for computing the heat resistance by rapidly heating the mold by an electric arc, as well as analysis of comparative data on quartz, dinas, and electric-corundum molds from the standpoint of the developed criterial-evaluation theory. In this case, the heat resistance is of one-time character, as this mold sustains only a single casting. Computational and experimental data indicate a low heat resistance of β-quartz, making them non-recommendable for annealing and metal pouring if there is not supporting filler. Molds based on electric-corundum or dinas fillers are free of such drawbacks, with the latter being considerably cheaper. The use of tridymited dinas powders is effective after grinding the spent dinas lining of electric furnaces.