Desenvolvimento de um revestimento à base de argila refratária para o processo de fundição com poliestireno expandido

Abstract

Expanded polystyrene casting is a casting process that makes use of an expandable polystyrene model to obtain metal parts. It consists in the degradation of the model contained in a sand mold, when in contact with liquid metal. The metal penetrates the mold through a system of feeding channels, and then, because it is surrounded by refractory material, the metal conforms to the mold where the model was. For the process to occur properly, an effective refractory lining is required, which gives the mold resistance during the pouring of the metal. The technique used in practical classes at the Foundry Laboratory of the Federal University of Ceará did not present satisfactory results for parts with medium and large dimensions. In order to solve this problem, tests were conducted with a coating, based on refractory clay, to see if it meets the requirements for obtaining castings with good finishing, allowing the production of parts without dimensional limits. The coating showed good results, because it was possible to manufacture parts with larger dimensions. However, the part was not free of defects.