Pitting Corrosion Resistance of a 316L Stainless Steel Manufactured by the Direct Metal Laser Sintering Process

摘要

Direct metal laser sintering (DMLS) is an additive manufacturing process that utilizes a laser to sinter powdered metal to make geometrically complex parts. However, DMLS generally produces material with lower mechanical performance and higher anisotropy as compared to conventional manufacturing approaches of the same material. Furthermore, components made by DMLS are believed to be more vulnerable to corrosion due to the presence of residual porosity, as well as laser induced microstructural deformations. This research focuses on the evaluation of the pitting corrosion resistance of 316L stainless steel manufactured using DMLS. Rolled 316L stainless steel specimens with similar chemical composition were used as a reference to compare their microstructural characteristics, porosity and pitting corrosion resistance. The microstructure of the DMLS samples was also compared to specimens annealed to eliminate laser induced scan tracks. Porosity of the DMLS specimens were determined per ASTM B311. Profilometry, compositional analysis and quantification of the corrosion resistance were performed, before and after the corrosion pitting resistance test, per ASTM G48 Method A (ferric chloride pitting test).