SCC of Oil and Gas Pipeline in High-pH Environment

In the experiment,a study was made of SCC mechanism of the X70 pipeline steel in a high pH value soil environment,which was simulated in Na2CO3+NaHCO3 solution,the cracking mode is intergranular with the mechanism of anode dissolution.The susceptibility to SCC increased with the decrease of the cathodic potentials.With the extra-electric potential moving negatively,X70 steel SCC sensitivity increase.In the anodic polarization electric potential area,X70 steel SCC sensitivity reduces rapidly with the extra-electric potential moving positively.The results can be used as reference for preventing the stress corrosion of operating pipelines and new gas pipelines.