An optimization of processing parameters and casting quality in the expendable pattern casting (EPC) process

The expendable pattern casting (EPC) process has been studied from several directions in order to optimize processing parameters and casting quality. A brief review is presented in Paper 1. Paper 2 describes the effect of vent-holes inside the pattern on mold filling and casting quality in the EPC process. It is found that under the same casting conditions, faster mold filling speed and fewer surface defects occurred in castings made from patterns with vent-holes for iron castings, while very little difference was found for aluminum castings poured below about 730C (1346F). Paper 3 includes an investigation of mold filling in thin section castings produced by the process. The fluidity in aluminum alloys was found to depend on a complex relationship between pouring temperature and the mechanism by which the decomposition products from the foam pattern were removed through the refractory coating. In gray iron, fluidity depends on the more rapid decomposition of the foam and rapid transport of gaseous decomposition products through the coating. High permeability coatings and increased metallostatic pressure improve the fluidity of both aluminum and iron castings. Paper 4 is related to the transport of decomposition products in the unbonded sand. These transformations suggest that transfer of heat into and through the unbonded sand is dependent on both heat and mass transfer. All the experiments were conducted for both aluminum and gray iron --Abstract, page iv