Application of polymer materials for production of evaporative pattern and development of new casting process

Abstract

In this paper, results of the investigation of the polymer materials for evaporate patterns and their application in the new casting method (EPC process) are presented. The basic characteristic of EPC process is that patterns and gating of moulds, made of polymers, stay in the cast till the liquid metal inflow. In contact with liquid metal, intensely, in relatively short time, polymer pattern is been decomposing and evaporating , accompanied by castings crystallization. In order to achieve qualitative and profitable castings production by the EPC process it is necessary to reach the balance in the system: evaporable polymer pattern-liquid metal-refractory coat-sandy cast in the phase of metal inflow, decomposition and evaporation of polymer pattern, formation and soldification of castings. Results of this investigation of this process relate on application of puffed polystyrene of various densities (kg/m3): 18, 20, 25. Application of lower density polymer (20 kg/m3) gave positive results on structure and properties of silumina castings obtained using this casting method.