Manufacturing and mechanical performance of a large-scale stainless steel vessel fabricated by wire-arc direct energy deposition

Wire-arc direct energy deposition was used in this study to manufacture a standing pressure vessel made of stainless steel. Considering the thickness of the additively manufactured sections, the fabricated part was divided into two major components: the shell and the head. The shell with a nominal wall thickness of 5 mm was manufactured using a single-pass technique, while the relatively thicker head, with a maximum thickness of 30 mm, was fabricated using a multi pass approach. The transition from the shell to the 15–30 mm thick head was done by variating wall thickness, enabled by additive manufacturing. After additive manufacturing, the full-scale component was tested up to the maximum internal water pressure of 111 bar (defined per the vessel's industrial application). Further, to evaluate the mechanical properties of the additively manufactured steel and the effects of pressure loads on it, quasi-static tensile and fatigue tests were conducted on coupons prepared from the material in two conditions: as-built (without any preload) and preloaded (after the pressure test) extracted from various sections. Finally, metallurgical characterization was performed to establish a correlation between the microstructural features and the mechanical performance. The results showed that it is possible to manufacture high-performance and quality pressure vessels using the wire-arc direct energy deposition method.