Characterization of an Austenitic Stainless Steel Preform Deposited by Wire Arc Additive Manufacturing

This work aimed to evaluate the chemical composition, microstructure and mechanical and electrochemical behavior of the 316L stainless steel manufactured by WAAM, comparing it with a sample of the same alloy in the annealed condition. The results indicate that the use of ER316LSi wire produces a component with chemical composition equivalent to the conventional 316L alloy. However, the microstructure of the deposited material is different with the presence of ferrite in an austenitic matrix. Two regions whose microstructure had different morphologies were also identified. In the region close to the fusion line between the deposited layers, the austenite grains are smaller, with a higher concentration of ferrite, causing an increase in microhardness in this region, when compared to the region more at the center of each layer. The WAAM process caused a decrease in the mechanical strength properties of the alloy, however it still meets the minimum requirements for most industrial applications required for the material studied. The electrochemical results in simulated seawater solution indicate that the corrosion resistance of the deposited sample is similar to that of the conventional specimen, with the potential for the passivating layer of the first to be superior to that of the second.