Effects of Process-Induced Defects on the Corrosion of Additively Manufactured Stainless Steel 304L

Abstract

This study investigates the impact of process-induced defects such as gas pores, lack of fusions, and surface roughness on corrosion behavior of stainless steel 304L (SS304L) fabricated by laser powder bed fusion additive manufacturing. Specimens are printed with optimized process parameters but selected from different locations on the build plate. Parallel and perpendicular surfaces to the build direction are investigated and compared with corrosion properties of wrought SS304L in 5 wt% NaCl. The results reveal significant difference in corrosion behavior among specimens due to variations in their defect features. Pitting potential, pit initiation, and growth rates are found to be influenced by specimen location on the build plate. The specimen located in downstream of the shielding gas flow shows the least corrosion resistance. While no clear trends are observed between some corrosion properties and defect features, other properties show strong correlations. For example, no trend is observed for the corrosion properties in relation to pore average area fraction. However, strong correlations are observed for the corrosion properties as functions of defects maximum area. Corrosion properties linearly deteriorate as the defects maximum area increases. Roughness shows a mixed relationship with pitting potential. Comprehensive discussions on all these effects are presented.