Comparative Statistical Analysis of Pitting in Two 2205 Duplex Stainless Steel Variants

Abstract

The inherent variability of pitting poses challenges in accurately evaluating the pitting resistance due to potential disparities in test results. This study compares the pitting resistance of two commercial 2205 duplex stainless steels. Counterintuitively, 2205-B, despite having a higher Pitting Resistance Equivalent Number and better passive film performance, exhibited a lower Critical Pitting Temperature. Through the potentiostatic pulse test and potentiostatic polarization, it was observed that 2205-B had a greater number of pitting initiation sites. Further investigation, using SEM inclusion statistics, revealed an increased presence of inclusions rich in calcium oxides as the underlying cause of this unexpected phenomenon.