Wire arc additive manufacturing (WAAM), also known as directed energy deposition (DED) process, is an efficient additive manufacturing technology, offers high potential to rapidly fabricate large-scale parts with complex geometries layer-by-layer. However, the fundamental understanding of the fatigue behaviour of such parts and the material requirements need to be significantly improved at all levels before this unique technology can be implemented for critical applications. This work aims to investigate the fatigue behaviour of WAAM built ER70S-6 steel under uniaxial, torsion and multiaxial loading conditions. Specimens were extracted in two different orientations: vertical and horizontal, to explore if the orientation direction has any effect on the fatigue results. Scanning Electron Microscopy (SEM) was conducted to examine the fracture surface of broken specimens and identify crack initiation regions and fracture mechanisms. The obtained results were compared with the fatigue data available in the literature on common structural steels fabricated using conventional welding and WAAM technique, showing similar fatigue behaviour with wrought S355 specimens. Moreover, the uniaxial data set on ER70S-6 WAAM specimens was evaluated according to the DNV RP-C203 standard for continuous welds, demonstrating advantageous fatigue resistance in the examined material.

电弧增材制造 (WAAM)，也称为定向能量沉积 (DED) 工艺，是一种高效的增材制造技术，为逐层快速制造具有复杂几何形状的大型零件提供了巨大的潜力。然而，在将这种独特的技术应用于关键应用之前，需要在各个层面上显着提高对此类零件的疲劳行为和材料要求的基本理解。本工作旨在研究 WAAM 制造的 ER70S-6 钢在单轴、扭转和多轴载荷条件下的疲劳行为。从两个不同的方向提取试样：垂直和水平，以探索方向方向是否对疲劳结果有任何影响。进行扫描电子显微镜 (SEM) 以检查断裂试样的断裂表面并确定裂纹起始区域和断裂机制。将获得的结果与文献中可用的关于使用传统焊接和 WAAM 技术制造的普通结构钢的疲劳数据进行比较，显示出与锻造 S355 试样相似的疲劳行为。此外，ER70S-6 WAAM 试样的单轴数据集根据 DNV RP-C203 连续焊缝标准进行了评估，证明了所检查材料具有优越的抗疲劳性。显示与锻造 S355 试样相似的疲劳行为。此外，ER70S-6 WAAM 试样的单轴数据集根据 DNV RP-C203 连续焊缝标准进行了评估，证明了所检查材料具有优越的抗疲劳性。显示与锻造 S355 试样相似的疲劳行为。此外，ER70S-6 WAAM 试样的单轴数据集根据 DNV RP-C203 连续焊缝标准进行了评估，证明了所检查材料具有优越的抗疲劳性。