Stahlbauknoten sind Verbindungselemente in Bauwerken. Sie haben die Aufgabe, verschiedene Bauteile wie Träger und Stützen in einem Bauwerk miteinander zu verbinden. In der konventionellen Fertigung werden diese Anschlusselemente vor allem durch sehr einfach zu fertigende und montierende Geometrien realisiert. Hierfür wird das Material häufig unwirtschaftlich eingesetzt. Dies gilt sowohl für Standardanschlüsse als auch für individuelle Knotenausführungen. Konstruktionen, welche über eher einfache Knoten verfügen, sind bspw. Industriehallen. Eine Konstruktion, welche ausschließlich aus Individualknoten besteht, ist die Gitterschale.

Wire arc additive manufacturing (WAAM) of titanium parts shows promising potential for aerospace application due to its high deposition rates allowing a fast and economical production of large integral parts. However, due to the demands of aerospace industry an extensive qualification procedure is necessary to enable the parts as ready to fly. Nowadays, qualification for additive manufactured parts is a time-consuming process, so the advantages in additive manufacturing cannot be fully utilized. For this reason, a complete process qualification for WAAM would reduce the costs drastically in contrast to qualifying manufactured parts individually. As a first step the robustness and reproducibility of the energy reduced WAAM process was investigated. Thick-walled samples are manufactured layer by layer with an oscillating welding head motion. The mechanical properties of the samples are compared on an adequate statistical basis. Microstructural-and computer tomography analysis are conducted to comprehend shown interactions. The reproducibility is investigated in dependence of different heat treatment states, different directions of mechanical testing and two manufacturing systems of the same type.

SYNOPSIS Wire-arc additive manufacturing (WAAM) is a directed-energy deposition technology that uses arc welding procedures to produce computer-aided designed parts, such as three-dimensional printed metal components. A challenge of additive manufacturing is the anisotropy. Interstitial elements play a significant role in the mechanical properties of Ti6Al4V of different grades. In this research, the mechanical properties of Grade 5 and Grade 23 Ti6Al4V were compared for this application. Samples were extracted from WAAM-produced Ti6Al4V walls in different directions (horizontal and vertical) and at different positions (top and bottom). The samples were subjected to optical microscopy and tensile and hardness tests. Grade 5 Ti6Al4V samples were found to have greater strength, greater hardness, and lower ductility, owing to the higher content of interstitial elements compared with Grade 23. The bottom samples had higher strength than the top samples, which is attributed to thermal cycling during manufacturing, resulting in different microstructures. Keywords: Ti6Al4V, wire-arc additive manufacturing, anisotropy, heat accumulation, interstitial elements.