Progress of research on key influencing factors of stress corrosion cracking of X80 buried pipeline

With the rapid development of the construction of high-pressure, large-diameter and long-distance X80 pipelines in China, Stress Corrosion Cracking (SCC) has become an important factor threatening the safe operation of pipelines. Herein, the key influencing factors of SCC of X80 pipeline steel in soil environment were summarized and analyzed. The influence of Alternating Current (AC) stray current on the SCC behavior of X80 pipeline steel and its influencing mechanism were analyzed, and it was pointed out that the alternating current and the elastic stress can cooperate with each other to jointly promote the anodic dissolution of X80 pipeline steel and destroy the state of dense corrosion product film on the steel surface, further accelerating the corrosion. In addition, the research status of the SCC mechanism of pipeline steel caused by Sulfate Reducing Bacteria (SRB) in soil environment was reviewed. It was concluded that the microbiologically-assisted cracking mechanism of X80 pipeline steel was mainly associated with the physiological activity of bacteria, its metabolites and the formation of biological film. Finally, suggestions on the selection of cathodic protection potential of X80 pipeline steel under SRB were proposed. Further, it is also recommended to include the microbial factors into the SCC evaluation system of pipeline steel. Therefore, the research results can provide theoretical guidance for the design and safety service of high-strength steel pipeline in China.