Experimental investigation on the geometric characteristics and mechanical properties of WAAM S308L stainless steel

Wire arc additive manufacturing (WAAM) is an emerging metal 3D printing technology, and it is deemed to be suitable for constructional sector due to its high fabrication speed, flexibility, and cost efficiency. This paper investigates the geometric characteristics and mechanical properties of WAAM S308L stainless steel plate and tube through experimental investigation. 3D scanning was employed for geometric measurement to reveal the variations in the geometric properties of the WAAM S308L specimens. In addition, the monotonic tensile test, Vickers hardness test, bend test, and Charpy V-notch impact tests were conducted to assess its mechanical properties. The effects of specimen shape and loading directions relative to the material deposition orientation on the mechanical properties were examined. Material anisotropy behaviour was observed, as the 45° specimen exhibited 14% higher strength and an 80% higher Young’s modulus compared to the 90° specimen. Excellent ductility was found, as indicated by the values of ratios σ u / σ 0.2 ≥ 1.1, ɛ u / ɛ 0.2 ≥ 15, and ɛ u ≥ 15%. The 45° sample exhibited approximately 8% greater impact energy absorption ability than the 90° sample. Curved tensile specimens exhibited a 20% higher 0.2% proof strength than plate specimens. Based on the tensile test results, the Ramberg-Osgood model is adopted to describe the full range of the stress-strain curve. Additionally, the plane orthotropic model and Hill’s yield criterion are used to accurately model the material’s elastic and plastic anisotropic behaviour. Overall, the investigated WAAM S308 L stainless steel exhibited obvious anisotropy in the mechanical properties, with qualified strength, ductility, and impact toughness for engineering practice.