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.

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.

Due to the inherent properties of the process, arc-based generative manufacturing offers the possibility, of specifically applying different material properties locally. One possibility to realize this is the use of different materials. Three approaches are presented to illustrate this option. First, anisotropic behavior in the welding direction is generated. For this purpose, a FeNi36 is specifically combined with a low-alloy ultra-high-strength fine-grained structural steel filler metal. It will be shown that the integral component properties can be specifically adjusted in the welding direction. In addition, the metallurgical and welding characteristics will be discussed. As a second possibility, the use of well plasticizable materials to locally increase the material strength under cyclic loading with locally notched components is presented. For this purpose, an austenitic FeNi36 with good plasticizability and a good yield strength ratio for the application was applied to a fillet weld of a high-strength fine-grained structural steel in the weld seam toe. It is shown that the tolerable cyclic load can be improved by 35% by this procedure. Thirdly, it is shown that the required thickness of corrosion protection layers can be reduced by 50% through a targeted production sequence in arc-based generative manufacturing.

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