Effects of different post surface treatments on the surface characteristics, corrosion resistance and metal migration from L-PBF additively manufactured 316L stainless steel

Additive manufacturing (AM) using Laser Powder Bed Fusion (L-PBF) enables the fabrication of complex metal components with high precision. However, the as-printed surfaces often exhibit high roughness, residual stresses, and partially fused particles, which can negatively impact the mechanical performance, corrosion resistance, and fatigue life. Surface treatments are therefore required to improve surface integrity, reduce defects, and enhance functional properties such as corrosion resistance. This study explores the impact of chemical and mechanical post-processing methods including pickling, clean hot isostatic pressure (HIP), Hirtization, shot peening (SP), and isotropic super finishing (C.A.S.E.) on the microstructure, surface composition and topography of L-PBF printed HIP treated 316L stainless steel surfaces in relation to their corrosion resistance and extent of metal dissolution in artificial tap water with and without chlorides (1 and 3 wt% Cl⁻). Corrosion studies were also performed in NaCl (2.1 wt% Cl⁻) based on the ASTM G61 standard. The utilization of a combination of electrochemical, chemical, microscopic, and spectroscopic techniques discerned notable differences for the differently surface treated AM 316L in terms of microstructure, surface topography, surface roughness, surface oxide composition and barrier properties, metal dissolution, corrosion resistance as well as pitting corrosion resistance.