Evaluation of stresses caused by electrochemical hydrogenation of pipe carbon steel

The internal corrosion of gas steel pipelines can be accompanied by electrochemical hydrogenation, and hydrogen transportation can intensify this process. A method for the study of stresses in steel caused by electrolytic hydrogenation was developed. It consists of preliminary rigid loading of specimens in the elastic or plastic regions, electrolytic hydrogenation, and recording of stresses. On the example of 17H1S pipe steel (an analog of API 5L X52), the occurrence of internal tensile stresses under the action of hydrogen is established. The amplitude of stresses and their reversibility depend on both the hydrogenation intensity and the previous load’s character. The obtained results are analyzed considering different states of hydrogen in the steel—diffusible and trapped hydrogen in the microstructure defects.