Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The electrochemical corrosion behavior of X70 steel in CO2 saturated solution with various concentrations of acetic acid was studied by means of potentiodynamic polarization measurement and EIS. Whilst the influence of acetic acid on the top localized corrosion (TLC) of X70 steel pipelines was examined in a set of high temperature and high pressure autoclave. The results showed that in the CO2 saturated solution, the X70 steel was inactive state. While the free corrosion potential of X70 steel shifted positively and its corrosion current density increased with the increasing concentration of acetic acid, which may be related to the rising H+ concentration, so that the cathodic reaction was promoted. In addition, because of the presence of acetic acid, the corrosion scale become loose and easy to detach from the substrate. Finally a pitting corrosion model was proposed to describe the initiation and evolution of the pitting process.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: none
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: With the increasingly exploiting the gas field, several corrosion related failure cases, such as perforation and fracture of tubing steel did occurr in Xushen gas fields, which was thought to be the result of CO2 induced localized corrosion. In order to reveal the nature of those failure cases, the corrosion behavior of N80 steel a commonly used material for pipelines, in a high temperature and high pressure environment was studied, which arms to simulate the CO2 induced localized corrosion in the actual gas well processing practice, thereby to figure out the relation of the sensitivity to corrosion of the tubing steel with the relavant processing parameters. By characterizing the corrosion morphology and the sensitivity to localized corrosion and summing up the effect of environmental factors (temperature and CO2 partial pressure) on the CO2 induced localized corrosion of N80 steel, a corrosion map could be constructed to describe the relation of corrosion types of the N80 steel with the processing parameters temperature and CO2 partial pressure etc., thereafter, a prediction model for configuring a range of environment parameters, within which the N80 steel would be sensitive to the CO2 induced localized corrosion. Finally, it is noted that the prediction of corrosion types and the range of parameters responsible to the CO2 induced localized corrosion of N80 steel show a good agreement with the observation of the practical failure cases in Xushen gas fields.