Mechanical testing and microstructural analysis of wire laser metal deposited stainless steel

Abstract Laser metal deposition (DED‐LB), or wire laser beam directed energy deposition (DED‐LB), is a metal 3D printing technique with growing appeal in civil engineering due to its efficiency and cost‐effectiveness in producing large‐scale components. However, limited data on the mechanical and geometric properties of DED‐LB steels hinder broader adoption. This study presents a comprehensive experimental investigation of ER 308LSi stainless steel DED‐LB plates. Laser scanning, tensile testing and microstructural characterisation were conducted on 2 mm and 8 mm thick coupons, with varying surface finishes and orientations. The results showed minimal geometric irregularity and comparable mechanical properties between as‐built and machined specimens. Thinner coupons exhibited reduced strengths and greater anisotropy, attributed to coarser grains and a strong crystallographic texture. An or‐thotropic constitutive model, adapted from WAAM stainless steel, was successfully applied to describe the material's anisotropic behaviour in both the elastic and inelastic regimes. The findings highlight the potential for using DED‐LB in construction, offering a viable alternative for fabricating large‐scale metal components of complex geometries.