2013 Frank Newman Speller Award Lecture: Integrity Management of Natural Gas and Petroleum Pipelines Subject to Stress Corrosion Cracking

Stress corrosion cracking (SCC) can be a serious threat to the integrity of natural gas and petroleum pipelines. This paper describes how the pipeline industry responded to this threat by performing a comprehensive research program to determine the cause(s) of the failures and investigate various techniques for preventing future failures. The paper focuses on a relatively concise list of discoveries that have had a measurable impact on mitigation of the SCC threat. Starting with the first recognized SCC failure in 1965, the research is described in which the intergranular form of cracking (known as high-pH SCC or classical SCC) was investigated to identify the causative agent and the controlling metallurgical, environmental, and stress-related factors. In the 1980s, a second, transgranular form of SCC (near-neutral-pH SCC) was discovered in Canada, resulting in a similar scope of research activities designed to develop mitigation methods for this form of cracking. The paper then discusses how the information developed in these research programs is incorporated into pipeline integrity management programs.