In this study, the monotonic and cyclic material properties of steel material of medium static strength produced additively in the wire arc additive manufacturing (WAAM) process were investigated. This investigated material is expected to be particularly applicable to the field of mechanical engineering, for which practical applications of the WAAM process are still pending and for which hardly any characteristic values can be found in the literature so far. The focus of the investigation was, on the one hand, to determine how the material characteristics are influenced by the load direction in relation to the layered structure and, on the other hand, how they are affected by different interlayer temperatures. For this purpose, monotonic tensile tests were carried out at room temperature as well as at elevated temperatures, and the cyclic material properties were determined. In addition, the hardness of the material and the residual stresses induced during production were measured and compared. In addition to the provision of characteristic properties for the investigated material, it was aimed to determine the extent to which the interlayer temperature influences the strength characteristics, since this can have a considerable influence on the production times and, thus, the economic efficiency of the process.

The present investigations on generative manufacturing using metallic materials pursue the idea of transferring the microscopic structural morphology of a dual-phase steel in modified form to the macroscopic level. The aim is to be able to join materials of different lattice modifications and to combine their positive properties. This applies in particular to the combination of high tensile strength and good formability. For this investigation, a specimen was created from a high-strength ferritic/martensitic (25%) and an austenitic (75%) material with a defined welding sequence. The specimen was deliberately manufactured anisotropically using welding layers in order to quantify its properties. Tensile tests were performed on specimens with different weld seam orientations to determine the direction-dependent properties. As can be proven by the results, the application of welding processes with different materials results in an anisotropic behaviour in generative manufacturing. With regard to tensile strength and elongation, there is an integral value of the mechanical-technological properties of both base materials. The existing anisotropy can be utilized with regard to the design by adapting the alignment of the weld layers to the load.

New alloys are needed to adapt the material properties and to improve the weldability of arc-based additive manufacturing processes. The classic development of welding filler materials is time-consuming and cost-intensive. For this reason, an alternative alloy concept is investigated and qualified here. This is based on the thin-film coating of welding filler materials by means of PVD coating. An HSLA steel DIN EN ISO 14341-A G 50 7 M21 is used as the base material. This is alloyed with the elements Al, Cr, Nb, Ni and Ti by means of PVD thin-film coating. This procedure represents an alternative alloy concept. In the scope of the qualification, the influence of the process and material properties is investigated, and the alternative alloying concept is compared with the classical alloying concept of secondary metallurgy. The investigations have shown that the thin film coating on the surface of the welding filler metal affects the process properties in the form of a changed arc length. Furthermore, the mechanical properties and the effect on the microstructure morphology were investigated. These were compared in the same chemical composition with a Mn4Ni2CrMo produced by secondary metallurgy. The results are in agreement with regard to the mechanical properties and the effect on the microstructure morphology.