Stress Corrosion Cracking of X80 Pipeline Steel in Near-Neutral pH Environment under Constant Load Tests with and without Preload

Abstract

Constant load tests in NS4 solution purged with N2–5%CO2 gas mixture were conducted on American Petroleum Institute (API) X80 pipeline steel applied in the 2nd West-East Gas Pipeline project with and without preload. The results show that cracks could initiate and propagate in X80 pipeline steel in near-neutral pH environment under a constant load condition. The life of crack initiation and propagation increased with decreasing applied stress. Preload did not change its corrosion behavior obviously. However, preload reduced the time for crack initiation.