Mechanical Analysis of Thick-Walled Low-Carbon Steel Structures Produced by Wire Arc Additive Manufacturing with Zig-Zag Trajectories

This study investigates the mechanical properties of multilayer thick WAAM components using a zigzag deposition strategy. Four different low carbon steel (ER70S-6) walls with two deposition angles and two turning radii were evaluated. The comprehensive design of experiment focuses on microstructural analysis and mechanical properties, including hardness, tensile strength, and Charpy V-Notch (CVN). Non-destructive Testing (NDT), including ultrasound and radiography, was also performed to assess the integrity of the wall. The fracture surfaces from CVN and tensile test samples were examined with Scanning Electron Microscope. The results reveal a negligible anisotropy of global mechanical properties and a limited influence of deposition angle and turning radius. Overall, CVN results have shown ductile failure with a few brittle outliers. These results suggest that the selected deposition strategy does not have a significant effect on global mechanical properties, which showed an isotropic behaviour. Nevertheless, the CVN outliers underline the critical role of local microstructural heterogeneities in fracture toughness. These findings contribute to the characterisation of the WAAM process for thick parts.