A contactless melt pool manipulation during laser deep-penetration welding can be realized by employing electromagnetic volume forces. In order to improve the melt pool dilution for the case of welding with filler material, low-frequency magnetic fields aligned coaxially to the laser beam have been used. The aim of this work was to identify the dominating interaction mechanism in case of low-frequency magnetic fields used in laser beam deep-penetration welding. By means of experimental and numerical investigations the dominating mechanism could be identified as a flow-induced, periodic magnetic melt flow resistance that causes a periodic deflection of the melt flow. By introducing a novel procedure to characterize the element distribution in weld seams, the significant improvement in terms of homogeneity of the element distribution generated by the low-frequency melt flow manipulation could also be shown
