Corrosion Failure Analysis of 316L Stainless Steel Exposed to the China's Bohai Sea Water‐Air Interfacial Environment for 2.5 years

ABSTRACT This work aims to investigate the corrosion electrochemical behavior of 316L stainless steel (SS) exposed to the seawater‐air interfacial environment in China's Bohai Sea for 2.5 years. A floating platform was established for a 2.5 year on‐site exposure test of large‐scale 316L SS specimens (200 mm × 1000 mm × 3 mm) in the Bohai Strait, with the exposed surface divided into splash, waterline, and full immersion zones. Corrosion behaviors were analyzed via morphology observation and electrochemical tests. Results showed the full immersion zone had the severest corrosion (deepest pits, thickest rust, heaviest biofouling), followed by the splash zone, while the waterline zone was mildest. Electrochemically, the waterline zone exhibited the highest corrosion potential, polarization resistance, and oxide film thickness, indicating optimal corrosion resistance. Barnacles accelerated corrosion in the full immersion zone via synergistic mechanical damage and biochemical effects. This study provides references for marine engineering material selection and corrosion protection of SS.