Estimation 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 hydrogen charging has been developed. It consists in preliminary rigid loading of specimens in the elastic or plastic regions, electro­lytic hydrogen charging and recording of stres­ses. On the example of 17G1С pipe steel (an analogue of API 5L X52), the occurrence of internal tensile stresses under the action of hydrogen is established. The amplitude of stres­ses and their reversibility depended on both the intensity of hydrogen charging and the character of the previous load. The obtained results were analyzed taking into account the different state of hydrogen in the steel – diffusible and trapped in defects of the microstruc­ture.