MECHANICAL AND MICROSTRUCTURAL EFFECTS ON MEDIUM CARBON STEEL WELD JOINTS WHEN A GMAW PROCESS IS USED TO REPAIR STRUCTURAL COMPONENTS USED IN THE MANUFACTURING OF HEAVY MINING EQUIPMENT

摘要

Meet the technical specifications defined by the design engineering department is a critical factor to have of a good performance during the normal life cycle of heavy mining equipment. This study was done to determine how the repair process carried out in order to recover structural components that did not meet the proper quality criteria after the inspection process, can alter the microstructure and the mechanical properties of the product used in the construction of heavy mining equipment. As the repair process can be done not only once, but twice and until three times using a manual GMAW process, this study was carried out under controlled conditions and using similar process parameters as those used in the manufacturing process. A set of four specimens were prepared, one without any repair, and the other three with one, two and three repairs. In order to evaluate the sanity of the welded unions and also the materials behavior of each one of the specimens, tensile, microhardness, macroetch, charpy, and metallographic tests were carried out.