Análise de falha dos parafusos de fixação da base do cavalete de sustentação do mastro de um caminhão perfuratriz

Abstract

Although in many cases go unnoticed, it is known that the bolts are present between the attachment elements in virtually all structures and equipment built by man. Not only in mining, but in the industry as a whole, are employed hundreds of bolts in various machines and equipment, since they provide greater ease in the process of assembly, disassembly and servicing of the equipment. While performing their role, which is to promote the union of two parts, the bolts do not draw attention. However, when they fail, they can become a source of serious problems and may reach catastrophic proportions. The Vale S. A. sent to the Laboratory of Metallography of the Federal University of Pará (LABMETAL - UFPA) eight bolts fractured, which were installed in two bearings mounting the easel base of the mast of a truck drill, and a new bolt, to be performed failure analysis, to identify possible reasons for failure, which resulted in the fall of the mast on the truck's cab, which took place in Mina do Sossego, municipality of Canaã dos Carajás, PA. According to the results, it can be stated that some bolts were out of specification of mechanical strength and that the main mechanism of failure was the cause of pit corrosion.