Fabricación de piezas fundidas de aluminio a partir de modelos colapsables de espuma de poliestireno y espuma de poliuretano

Abstract

The lost foam casting method uses the polystyrene foam traditionally as a base material for the manufacturing of collapsible models; this research seeks the use of new materials for this process, finding a viable option in the polyurethane foam. It starts with the manufacturing of the models of foam in both materials, which will be covered by four types of refractory paintings in order to find an optimal coating that gives the best surface finish to the melted casting. The variables involved in the casting process were studied, these include: characteristics of the molding sands, pouring temperature and interaction model-refractory paint. With the use of the Click2Cast Software was designed and analyzed the power system to be used in the smelting of aluminum parts. Optical metallography techniques, spectrometry and Brinell hardness test were used to characterize and quantify variations in microstructure and hardness in the base metal failure were also valued by casting or by the use of collapsible models. Based on these results, remedial measures were taken, obtaining significant improvements to the casted parts coming from polyurethane and polystyrene foam models, the surface finish of the polystyrene parts is slightly better however there is no difference between physical properties and chemical structure with the piece obtained of polyurethane therefore the polyurethane foam is a feasible alternative in the lost foam casting method.