Mechanical and geometrical properties of normal-strength additively manufactured steel structures

Metal Additive Manufacturing (AM) has found applications in diverse sectors such as medicine and aerospace, with growing recognition of its potential in the construction industry. Among these technologies, Wire Arc Additive Manufacturing (WAAM) has recently been employed in structural applications including the repair and strengthening of existing components and the fabrication of geometrically complex, often thin-walled, parts. Its capability to produce larger components with intricate geometries highlights its promise for future structural innovations. This study investigates the mechanical performance of normal-strength structural steel (ER70S-6) fabricated using WAAM, through a series of tensile and compressive coupon tests. Surface roughness is quantified for a variety of orientations via high precision laser scanning, and an idealized representation is proposed. The microstructure of different coupons was characterized using scanning electron microscopy and energy dispersive spectroscopy to investigate differences in ductility. Additionally, fracture behavior is evaluated using a Level 1 calibration method for the Lode Modified Void Growth Model (LMVGM), offering insight into the response over the full-range plastic deformation of the material. Moreover, a power-law model is proposed to capture the effect of surface roughness on the initiation of fracture.