Stress corrosion mechanism and susceptibility of X80 steel under a disbonded coating in an acidic soil solution

摘要

The stress corrosion mechanism and susceptibility of X80 steel under a disbonded coating in a simulated acidic soil solution was investigated by a disbonded coating simulation device. According to the ex situ slow strain rate tension (SSRT) tests and potentiodynamic polarization measurement results, the environmentally assisted cracking (EAC) process was controlled by both anodic dissolution (AD) and hydrogen embrittlement (HE), and the range of critical potential values for different EAC mechanisms were also confirmed. Due to the accumulation of H+ and Cl- at the bottom of the crevice under the disbonded coating, the X80 steel exhibited the highest EAC susceptibility. A low strain rate provides sufficient action time and allows the adequate diffusion of hydrogen atoms on the steel surface, thereby resulting in an increase in the EAC susceptibility of X80 steel.