Influence of the Current Level, Torch Angle and Distance to the Plate on the Weld Bead Geometry Using “Plasma-MIG” with Concentric Arcs

Abstract

An appropriate control of the welding pool is essential for obtaining welds in conformity with design specifications. The “Plasma-MIG” with concentric arcs process has appeared as an innovative option in this direction. Thus, this work aimed to expand the studies related to the influence of the balance of current between the consumable electrode and the external arc, to the torch angle and to torch-plate distance on the process performance. Bead on plate welds were carried out aiming to identify individually the effect of each of the variables on the bead geometry. The extern arc current was evaluated at four levels and the effect of the remaining parameters was evaluated at three levels. Increases of extern arc current promotes wider beads, deeper penetration, larger molten area and lower reinforcement. When the distance electrode-plate was lengthened, the reinforcement increased and the width, penetration and melt area decreased. Concerning the torch angle, the width and melt area increased and the reinforcement and penetration decreased when the position changes from pulling to pushing.

Key-words:
“Plasma-MIG”; Weld bead geometry; Concentric arcs; Welding parameters