Experimental verification of multi-physical modelling of the keyhole laser welding process

To investigate the influence of temperature dependant material properties on model results, 2D FEM calculations for thin sheets of AA5182 aluminium alloy were compared with real-time coaxial camera images of the laser welding process. The results show the importance of taking into account the latent heat of the solid-liquid phase transition in the model. Including temperature dependant values of the thermal conductivity and the specific heat slightly improved the model accuracy. The tendency of a shortening melt pool for higher values of the laser power could not be explained by this 2D model and is expected to be caused by a changing keyhole shape. In the FEM model results, the melt flow shows a clear recirculation with melt flowing forward on the centerline, from the tail region towards the keyhole