Numerical analysis of Al vapour effects in gas metal arc welding of Al alloys

Using an in-house three-dimensional (GMAW) process simulation tool, the effects of Al vapour in the arc welding of aluminium alloys for various welding currents have been studied. The mathematical model, which takes into account the effects of metal vapour, is described. A bead-on-Al-plate problem is then modelled, with and without consideration of the Al vapour for various welding currents. The effects of the Al vapour on the energy flow of the system and the resulting weld profile are examined. The calculated plasma temperatures are compared with measured temperatures. The change of heat input to the workpiece due to the presence of Al vapour is examined. Finally, the calculated weld profiles with and without consideration of Al vapour are compared with actual weld profiles. It is found that the presence of Al vapour reduces the arc temperature and the weld depth significantly.