Shaped Metal Deposition of 308 Austenitic Stainless Steel

Shaped Metal Deposition (SMD) is an innovative near net-shape technique for additive layer manufacturing, particularly suitable for rapid prototyping and repair of metal components where tooling is limited. This study investigates the application of type 308 austenitic stainless steel in SMD for the first time, aiming to produce components with enhanced corrosion resistance and ductility. Employing continuous layer-by-layer deposition utilizing conventional tungsten inert gas (TIG) welding in an Argon atmosphere, the research focuses on the microstructural behavior of 308 steel during the SMD process. The material's weldability is examined alongside the influence of cooling rates on the formation of austenite and ferrite phases, as well as the precipitation of chromium carbides at grain boundaries, which can compromise mechanical properties. Our findings indicate that while SMD allows for the creation of components with a dominated heat-affected zone (HAZ), attention must be paid to the potential degradation of ductility and corrosion resistance. This study contributes to the understanding of SMD processes and offers insights into optimizing material properties for aerospace and other demanding applications.