Influence of Annealing Temperature on Pitting Corrosion Resistance of 316L Stainless Steel Electropolished by Wiping Method

This study investigated annealing temperature influence on the structure and pitting corrosion resistance of 316L stainless steel surfaces electropolished using a wiping method. The 316L stainless steel specimens were annealed in air at 523 K, 623 K, and 723 K for 1 hr. After annealing at 523 K, the oxide film thickness on the 316L stainless steel surface increased from approximately 3.5 nm to 5.0 nm, and the pitting potential shifted in the positive direction. After annealing at 623 K, the oxide film thickness increased to approximately 15.5 nm. However, the corrosion resistance was decreased by cracks occurring in the oxide film. After annealing at 723 K, the corrosion resistance decreased considerably because of increased concentration of iron oxide phases on the oxide film surface. These results indicate approximately 523 K as the optimum annealing temperature for improving pitting corrosion resistance of 316L stainless steel electropolished using the wiping method.