Influência da preparação de juntas soldadas pelo Processo Arame Tubular na microestrutura e resistência mecânica do Aço Naval ASTM A131-A

Abstract

Back gouging is a process that occurs during welding for double welds and is defined as the removal of the weld metal and base metal from the first weld of a welded joint to ensure that there is no inadequate joint penetration or incomplete fusion between welds and metal base, where both result in stress points, and the cracks that can start and propagate as weld beads are deposited. The objective of this study is to analyze the microstructures and mechanical properties of the welded joint of ASTM A131-A steel, resulting from flux cored arc welding and back gouging by grinding. Optical and electronic microscopy with x-ray spectrometer of dispersive energy, were used to evaluate the microstructure and inclusions, the tensile test and nanoindentation were used to evaluate the mechanical resistance in the entire weld bead. Results showed that the depth of gouging can effectively reduce the mechanical strength of ASTM A131-A steel. The 5.0 mm gouged welded joint exhibited a more prominent reduction in strength than the 1.5 mm gouged welded joint, which, in turn, the 1.5 mm deep gouge had a reduction in manufacturing time of 28.27% for a 1300 mm long plate with 9.5 mm thickness.