Differences between arc models in laser hybrid arc welding upon weld bead stability and undercut formation

Abstract

In this study, three different arc modes are studied in laser hybrid arc welding with a gasmetal arc, i.e. Standard, Pulsed and Cold Metal Transfer mode. Originally developed forbeing able to weld thin materials, the pulsed mode is the favoured arc mode in both ordinaryarc welding and hybrid welding. The pulsed mode is a more controlled gas metal arc weldingprocess that uses less heat and is able to weld thinner materials than the spray mode processwith globular drop transfer. The cold metal transfer mode utilizes surface tension droptransfer, compared to the free flying drops governing the other modes and is thus even morecontrolled than the pulsed mode. The cold metal transfer mode is much colder than the otherarc modes and is considered to generate less undercuts and spatter than the other modes, byboth developers and users alike.This study compares welds made by the three arc modes for both low and highdeposition rates. The welds are studied by macrographs, scanning and high speed imaging.This study shows that the differences between drop transfer modes are partially eliminateddue to the presence of a laser keyhole. The main arguments to use either arc mode arediscussed.Godkänd; 2013; 20131210 (andbra