Effect of Heat Treatment on the Passive Film and Depassivation Behavior of Cr-Bearing Steel Reinforcement in an Alkaline Environment

Using Cr-bearing low-alloy steel is an effective preventive measure for marine structures, as it offers superior corrosion resistance when compared to plain carbon steel. However, remains unclear how quenching and tempering heat treatment, which commonly applied reinforcement in some specific environments improve its mechanical properties, affects resistance. In the present work, impact of treatment on passive film depassivation behavior 0.2C-1.4Mn-0.6Si-5Cr are studied. The results reveal that result grain refinement steel, increases hardness. this causes significant degradation critical [Cl−]/[OH−] ratio after determined be approximately 6.6 times lower than normalization, rate 1.6 higher. After tempering, predominantly comprises iron oxides hydroxides, with relatively high water content defect density. Additionally, FeII/FeIII low. comparison, exhibits resistance, formed offering highest level protection.