Stress Corrosion Cracking Mechanisms of UNS S32205 Duplex Stainless Steel in Carbonated Solution Induced by Chlorides

Abstract

Herein, the chloride-induced stress corrosion cracking (SCC) mechanisms of UNS S32205 duplex stainless steel (DSS) reinforcing bars in alkaline and carbonated solutions are studied. Electrochemical monitoring and mechanical properties were tested using linear polarization resistance and electrochemical impedance spectroscopy, coupled with the slow strain rate tensile test (SSRT) to evaluate the SCC behavior and unravel the pit-to-crack mechanisms. Pit initiation and crack morphology were identified by fractographic analysis, which revealed the transgranular (TG) SCC mechanism. HCO3− acidification enhanced the anodic dissolution kinetics, thus promoting a premature pit-to-crack transition, seen by the decrease in the maximum phase angle in the Bode plot at low frequencies (≈ 1 Hz) for the carbonated solution. The crack propagation rate for the carbonated solution increased by over 100% compared to the alkaline solution, coinciding with the lower phase angle from the Bode plots, as well as with the lower charge transfer resistance. Pit initiation was found at the TiN nonmetallic inclusion inside the ferrite phase cleavage facet, which developed TG-SCC.

Seawater Corrosion Resistance of Duplex Stainless Steel and the Axial Compressive Stiffness of Its Reinforced Concrete Columns

“…Duplex stainless steel is a resource-saving, high-performance steel product, and its production and application are consistent with the future development of stainless steel [1][2][3][4][5][6][7]. The development of ocean-related resources has always been a research hotspot.…”

“…Based on the lateral stiffness theory, the 18 short columns in the tests were taken as objects, and the calculations were conducted with the theoretical Equation (2). The comparison between the theoretical and test values for lateral stiffness is presented in Table 8.…”

Integrity Assessment of Stress Corrosion Cracking Susceptibility of Duplex UNS S32205 and Austenitic UNS S31653 Stainless Steel Reinforcements

“…UNS S32205 showed major areas of ductile areas, with microvoids and coalescence of dimples attributed to the ductile behavior of the γ-phase (see Figure 3a) [43]. However, when UNS S32205 developed brittle fracture, cracks on the ferrite facets were seen, thus showing that the α-phase is the more SCC-susceptible phase (see Figure 3d) [28,44]. UNS S31653 also developed microvoids and coalescence of dimples for the ductile fracture (see Figure 3b), nevertheless, for the brittle fracture, cracks inside the dimples were the predominant feature, besides the development of cleavage planes (see Figure 3e) [45].…”

“…However, a few studies are found on the SCC mechanisms of the steel reinforcement [27][28][29][30]. While it is less studied, SCC of the steel reinforcement causes a sudden brittle fracture, leading to a catastrophic failure without any previous sign of damage.…”

Electrochemical Corrosion Behavior of 310S Stainless Steel in Hot Concentrated Tap Water

“…Tap water contains anions (e.g., Cl − , HCO 3 − , SO 4 2− ) and cations (e.g., Ca 2+ , Mg 2+ ), which play important roles in the corrosion of heating tubes [9][10][11][12]. Cl − ions must adsorb on the metal surface and subsequently cause the breakdown of passive films and the occurrence of pitting corrosion.…”