Desenvolvimento de recobrimento refratário para poliestileno expandido no processo de fundição espuma-perdida

Abstract

According to Groover (2014, p. 121), “The expanded polystyrene foundry process uses a mold with compacted sand around a polystyrene foam model that is vaporized when the molten metal is poured into the mold.” This technique sparked interest from the Foundry Laboratory of the Federal University of Ceará (UFC) due to its ease in producing parts, this process being used for better learning of students in disciplines related to casting. Despite having a simple initial theory, this process is widely used in the automotive industry, using the lost-foam process for the production of automotive engines with the aid of automation for the production of expanded polystyrene models (Styrofoam®). This work is based on several researches carried out at the UFC Casting Laboratory. The TCC of Vaz Filho (2021) stands out, who developed a formula based on refractory coating, allowing the production of parts up to 30 centimeters. Additionally, the study of Oliveira (2023) is considered, in which a meticulous comparison was made between alumina and refractory clay, with the aim of determining which one would present the best properties in different aspects. During the study, eight different refractory coating recipes with the aim of analyzing their behavior under various conditions were tested. We evaluated each recipe based on criteria, including the ease of product application, the simplicity of shell removal after casting, and most importantly, whether the product maintained the characteristics of the expanded polystyrene mold. In the end, 3 recipes presented satisfactory results, presenting excellent results.