Magnetic pulse welding—investigation on the welding of high-strength aluminum alloys and steels as well as the influence of fluctuations in the production on the welding results for thin metal sheets

Abstract

As there has been an increasing demand for cold welding methods recently, this offers the chance and possibility to use the potential of magnetic pulse technology to its full extent. This is especially the case when joining different materials (steel–aluminum sheet metal welds) and having to adhere to the specific requirements of lightweight constructions, thus, giving this welding method a particular role. In this paper and the oral presentation, results of a publicly funded project will be presented (AiF-Nr. 18290 N/P1029). The focus lies on the weldability of mixed-material combinations through magnetic pulse technology and its reproducibility. Tests showed that, aside from the influence of the surface properties, it is the mechanical properties and chemical composition of the materials that are especially important for the process stability. The generated process window illustrates the aforementioned, whereby the lower curve—surface preparation—can be adapted to meet fluctuations and tolerances in the production. On a secondary level, the robustness of the process is shown as regards fluctuations and tolerances of the process. The results show relevant differences, especially for the alignment of the welding partners as even a change in the discharge energy influences the weld results. The influence of deviations from the angle for a parallel alignment of the metal sheets, the influence of fluctuations in the gap, and the increase in discharge energy are determined and characterized through destructive tests with fragmentation pattern analyses. In sum, the results show the high potential of magnetic pulse welding for the joining of mixed materials and show a high reproducibility of the welding results.