Experimental investigations on the arc's physical aspects and their implications on weld bead morphology and microstructure in TIG welding with an external longitudinal magnetic field

摘要

Works addressing the effects of longitudinal magnetic fields in arc welding are still scarce in the literature, and most of them have a theoretical approach. With that in mind, the present work aims to investigate, through an experimental approach, the effects of applying an external longitudinal magnetic field on the physical aspects of the arc and the applicability in TIG welding. For that, tests were carried out using welding currents of 50 A and 100 A and magnetic fields of up to 42 mT. As a result, changes in the stagnation pressure profile and arc constriction were verified. With the results, welding tests were performed in order to verify the effects of such changes in the weld bead morphology and microstructure. Showing that penetration could be reduced and the weld bead could be widened by increasing the external magnetic field intensity, yielding a more refined microstructure in the molten zone. Furthermore, the applied magnetic field direction was observed to have an effect on the unilateral displacement of the weld bead.