Modelling and experimental validation of moving tilted volumetric heat source in gas metal arc welding process

In this work, the effect of electrode's tilt angle on transient temperature distribution, heat affected zone width and weld bead geometry in gas metal arc welding process are investigated. Experimental, microstructure and analytical modelling studies of heat affected zone and fusion zone have been performed for different electrode tilt angles. Gaussian heat density distribution and ellipsoidal heat source shape were assumed to predict the transient temperature distribution in the welded plate. The analytical model for the transient temperature distribution in the welded plate considers heat transfers from molten droplets of the filler material, moving volumetric heat source, and convective and radiative heat losses from the welded plate. Decent agreement between the predicted and the experimental temperature distribution, heat affected zone and weld bead geometry is obtained. The comparison suggested that ellipsoidal heat source shape is quite appropriate for predicting the transient temperature distribution on the welded plate for gas metal arc welding process. It was found that the heat affected zone width increases with the decrease in tilt angle. Microstructural examination on samples revealed prominent grain growth in the heat affected zone, however, fine grain structure was observed in the fusion zone. The predictions for heat affected zone width and weld bead geometry are also validated with experiments performed in shop floor welding conditions. (C) 2016 Elsevier B.V. All rights reserved.