Scratch Beneath the Surface: Corrosion Performance of Wire-Based AM 308L Stainless Steel and the Effect of Surface Finish

Abstract

Electron beam additively manufactured (EBAM) materials provide a path for the rapid generation of 3D components, but widespread use is limited by the understanding of how this process can impact the mechanical behavior and corrosion susceptibility of these materials. Gaps in property-process-structure- performance relationships limit the ability to develop reasonable qualification pathways for EBAM materials, and unknown process effects may require significant testing in order to prove that material behavior remains unchanged from other manufacturing processes. This work strived to reduce these gaps in wire-fed AM processes by evaluating baseline corrosion performance of both EBAM and wire arc additive manufacturing (WAAM) Type 308L Stainless Steel (308L SS). Baseline corrosion testing in room temperature 3.5% NaCl solution was performed on two EBAM builds and one WAAM build. Testing was performed in the as-built surface condition, in the electropolished condition, and in a ground and polished condition. Mechanically polished samples demonstrated pitting behavior on par with conventionally welded material and 316L SS laser powder bed fusion material, indicating that there is no inherent susceptibility of mechanically ground and polished EBAM or WAAM 308L SS. As a whole, this work has begun to improve the understanding of corrosion performance of AM materials to guide post-processing techniques.