L51911 Conditions that Lead to the Generation of Stress Corrosion Cracking Environments - A Review

Abstract

Current knowledge of the conditions leading to generation of environments that cause stress corrosion cracking (SCC) of high-pressure pipelines was reviewed, and a database of references was compiled. In addition to the surface preparation of the steel pipe and the type of coating that is used, the level of cathodic protection (CP) reaching the pipe surface and the partial pressure of CO2 in the ground water are important factors. The balance between the level of CP reaching the surface and the CO2 partial pressure in the ground water is critical in determining the pH at the steel surface, and hence, whether high-pH SCC, near-neutral-pH SCC, or neither, occurs. Corrosion at pits and other localized sites may be a part of the SCC pre-initiation process. Under ground water conditions that simulate those of near-neutral-pH SCC, hydrogen enters and permeates line pipe steels. The findings of a review on conditions that lead to generation of stress corrosion cracking environments is presented in this report. The literature citations have been organized using Reference Manager, a searchable database of references. About 1,600 citations to references available in the literature as well as to industry reports are listed in the Reference Manager, covering all aspects of stress corrosion cracking, including issues relevant to generation of environments that cause SCC, such as coatings. Selected items from the Reference Manager database are listed in the Appendix of this report.