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In this paper, the stress corrosion cracking (SCC) behaviors of X100 pipeline steel are studied in a carbonate/bicarbonate solution with different concentrations of chloride (Cl−) by using slow stress-strain tests, electrochemical measurements, x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The effect of Cl− on the SCC process is discussed based on the change of surface state and the force of crack propagation. The results showed that the SCC susceptibility of the steel increased with the rise of Cl− concentration. Cl− promoted the SCC process by providing a high driving force for crack propagation and accelerating anodic dissolution. Furthermore, Cl− reduced the FeCO3 content in the film on the steel surface, which facilitated the initiation of SCC. [ABSTRACT FROM AUTHOR]

The effect of alternating magnetic field on electrochemical behavior of 316L and TA2 in simulated seawater was studied by potentiodynamic polarization, electrochemical impedance spectra, potentiostatic polarization, and surface morphology topology. Results show that the alternating magnetic field induces convection and enhances mass transport, which promote destruction of the passive film caused by chloride ion and accelerate cations to leave the electrode/solution interface, consequently resulting in dissolution of passive film and metal substrate of 316L. Changes of TA2 induced by magnetic field are quite weak due to superior resistance of TiO2 of the top layer of passive film. [ABSTRACT FROM AUTHOR]

The stress corrosion cracking (SCC) of 2205 duplex stainless steels (DSSs) with different microstructures in simulated sea environments were studied by electrochemical measurements, electron backscattered diffraction and slow strain rate tensile tests. Heat treatments were used to obtain different microstructures. The DSSs were held at 1350 and 850 °C for 30 min and then quenched in the water. The results showed that the DSSs had a higher SCC susceptibility in simulated shallow sea environment than in the simulated deep-sea environment. Electrochemical mechanism of the SCC process was controlled by environment factors (temperature, hydrostatic pressure and dissolved oxygen content). The mechanisms of SCC changed from anodic dissolution in the simulated shallow sea environment to hydrogen embrittlement in the simulated deep-sea environment. Moreover, the quenched DSSs, especially the steel held at 850 °C, were more vulnerable to SCC than as-received steel in the simulated sea environment due to the deterioration of the microstructure. [ABSTRACT FROM AUTHOR]

This study investigated the effect of flowing velocity and impact angle on the fluid-accelerated corrosion (FAC) of X65 pipeline steel in a wet CO2-containing environment by corrosion morphology analysis, electrochemical measurement, and hydromechanical numerical analysis. It has been found that the corrosion behavior was controlled by the ion diffusion rate and shear stress due to the flowing gas. With an increase in the flowing velocity, the pitting corrosion initially decreased and then increased when the flowing velocity exceeded 14 m/s; this increase is caused by the augmentation of shear stress. When the impact angle decreased, the position of serious corrosion gradually moved outwards. [ABSTRACT FROM AUTHOR]