Additive manufacturing with steel offers new opportunities for the construction sector. In particular, direct energy deposition (DED) processes such as Wire Arc Additive Manufacturing (WAAM or DED-Arc), are able to create large structures with a high degree of geometric freedom, like force-flow-optimized steel nodes and frameworks, as well as truss structures. By using high-strength steel, manufacturing times can be shortened because less material has to be applied. In order to enable the usage of WAAM components in the construction industry, profound knowledge of the material behavior is necessary. Based on reliable process parameters, extensive experimental and numerical investigations are carried out to characterize the influence of layer orientation and overhang angle on the mechanical parameters of WAAM high-strength low-alloy steel (HSLA) walls. The results have been compared to HSLA steel sheet material. It is shown that comparable characteristics exist for Young’s modulus E, yield strength $R_{p,0.2}$ and tensile strength $R_m$ with regard to civil engineering applications. The influence of the loading direction on the material level is similar. Only the yield strength shows a slight dependence on the layer orientation for WAAM walls (difference 4.5%). The overhang angle has no influence on the material parameters.

Additive manufacturing of metal components offers a high potential for many industrial applications due to the cost-efficient manufacturing of geometrically complex and individualized components, for example, to manufacture connections for steel constructions. Different process classes of metal additive manufacturing exist. The powder bed fusion and the directed energy deposition processes are especially relevant for industrial applications. In comparison, the powder bed fusion processes achieve a higher accuracy but have a lower build rate than directed energy deposition processes. This publication focuses on the combination of powder bed fusion of metals using a laser beam and directed energy deposition using a plasma arc for the fabrication of 316 L stainless steel. The differences in temperature profiles and solidification conditions between the two processes cause variations in the microstructure of the 316 L material. These microstructural differences lead each processed version of 316 L to develop distinct properties. The microstructure and mechanical properties were investigated in detail. All tensile specimens failed away from the interface. The integral tensile properties were in between the values of the individual materials. The microstructure showed five different zones. These were attributed to the different thermal characteristics of the two processes and the effect of the heat input of the directed energy deposition additive manufacturing on the powder bed fusion material, which was fabricated first. The results give insight into the differences in the metallurgical and mechanical properties of 316 L manufactured by these two processes. The results also highlight the importance of characterizing the process and material combination for applying a hybrid additive manufacturing process routine.