Effect of CO2 on Stress Corrosion of P110 Steel in Wet H2S and CO2 Environment
CO2对H2S/CO2环境中P110钢应力腐蚀的影响研究

Constant load tensile test, electrochemical corrosion measurement and SEM analysis were adopted to study the sulfide stress corrosion cracking (SSCC) of P110 steel in H2S/CO2 NACE standard solution. The results show that, in the initial stage of loading, the E corr of P110 steel drops sharply and increases slowly again after reaching a minimum value. Then the Eorr increases to constant value until fracture occurs, and the brittle cleavage fracture appears correspondingly. When the content of CO2 increasing to 17%, the Ecorr of P110 steel decreases, the corrosion current increases, the process of SSCC is speeding up, and thereby complete cleavage fracture appears correspondingly. With the content of CO2 further increasing, the Ecorr of P110 steel increases slightly, and the corrosion current decreases, the time to fracture is extended. When the content of CO2 increasing to 50%, small quantity of toughness dimples on the fracture surface appears correspondingly. This phenomenon has the relevance to the combination of competitive adsorption of H2S/CO2 on the surface of steel with tensile breakdown and regeneration of surface film on P110 steel in stress corrosion environment.