Arc-based additive manufacturing of steel components—comparison of wire- and powder-based variants

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Additive manufacturing of components, layer-by-layer, offers several advantages compared to conventional production technologies such as higher material utilization efficiency and increased geometric possibilities. Arc-based additive manufacturing processes have the additional advantage of an almost unlimited assembly space, higher deposition rates, and an improved utilization factor of raw materials. Up to now, the gas metal arc welding variant, cold metal transfer (CMT), and other wire-based process combinations have been used predominantly in this field. Disadvantages of wire-based methods are the restricted availability of different types of wire consumables, the wire feed rate directly coupled to the heat input, and the lack of possibility to create multi-material structures with one heat source in-situ. Within this work, the 3D plasma-metal deposition (3DPMD) method, based on a plasma powder deposition process is introduced. 3DPMD has some advantages compared to the established plasma powder process and wire-based CMT process. Basis for this evaluation is the production of geometrically complex structures by the different methods (CMT & 3DPMD) and their subsequent characterization. Structures are fabricated using welding robots with the path control directly generated from the CAD files. In summary, 3DPMD offers increased flexibility in terms of material selection as well as the possibility to build graded structures. By using subroutines realized from a special postprocessor, it is possible to generate metal structures with standard welding robots directly from the CAD drawings. Microstructures and properties are directly related to the process and therefore material-process-property relationships are discussed within this work.