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.
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