Improvement of pitting corrosion resistance of AISI type SS 304L in chloride medium
摘要
Chloride ions in the chemical, nuclear, pharmaceutical, food, marine, petrochemical industries, and body fluid medium cause pitting corrosion in stainless steel (SS). In this research, the pitting corrosion resistance behaviour of SS 304L was evaluated in simulated marine environment (SME) and simulated body fluid (SBF) solutions. A solution annealed coarse-grain (CG) SS 304L was severely plastic deformed (SPD, up to 90%) at liquid N2 temperature. This leads to the formation of ultra-fine grain (UFG) microstructure. UFG specimens were further annealed at 1050°C for 1-h, and gamma-ray irradiated separately at a dose of 7 kGy. Pitting was evidenced for the as-received CG, UFG-deformed and UFG-deformed, followed by annealed (1050°C for 1 h) specimens, whereas pitting corrosion was not observed for the UFG specimen after gamma-ray irradiation in both SME and SBF solutions.