ANÁLISES DE MELHORIAS EM TAMPA DE CAIXA DE PASSAGEM DE TRANSFORMADOR ELÉTRICO DE LIGA DE ALUMÍNIO SAE 305 FUNDIDA POR GRAVIDADE

Abstract

This work describes improvements in a cover, used in the junction box, high power transformer equipment, which is made of gravity cast / cupped SAE 305 aluminum alloy. Such an approach is necessary because a reasonable amount of castings presents defects such as shriveling, drills and porosities, which are evident after being machined. The objective of this work is, through tests and analysis compared to methodological articles of metallographies that can be applied, chemical composition analysis of the received batches, tests on the treatment of aluminum in the crucible and observation of the leakage temperature, to find a method that will repair or improve the appearances of these defects. Through the tests performed in the treatment, it was observed effectiveness in the use of nitrogen in the reduction of the defects, however due to its high cost becomes an unviable alternative. Therefore, sample 6 (50g scorifier (powder) + 100g degasser (powder)) also presented a satisfactory result, with approximately 80% reduction of the previous defects; besides being financially viable, its cost is 60% cheaper than nitrogen.