Corrosion mechanism of high temperature and O2 content in steamed CO2/O2/SO2 system and failure behavior of 20G steel on steam-injection pipelines

The corrosion mechanism and failure behavior of 20 G steel in steamed CO2/O2/SO2 environment (7.8 MPa, 100–301 °C) are studied. The surface characterization technology is adopted to analyze the corrosion rate and the microscopic morphology of corrosion product film, where the corrosive influencing factors are determined. The influence of temperature on the film formation kinetics is greater than that of cathodic reaction thermodynamics, wherein the corrosion product film has good performance for anti-corrosion. The interaction between H+ and Cl- leads to the degradation of mechanical properties. The residual-life evaluation model is proposed to recommend the reinspection period of the steam injection pipeline.