Analysis of the development of stress corrosion cracking in pipelines of compressor stations

Abstract

The problem of corrosion cracking in underground gas pipelines has been a focus of attention of gas-transporting enterprises for more than 15 years, but so far there is neither an unambiguous assessment of the main causes of this phenomenon nor acceptable methods for reducing it (except detection of stress corrosion cracking (SCC) flaws by means of in-tube flaw detection and the subsequent elimination of these flaws). One important feature of the manifestation of the problem of SCC in main gas pipelines is the selectivity of cracking (SCC is identified in a small fraction of pipes), the causes of which are unknown. It is still not clear whether this feature is due to the time delay of SCC or this effect has another origin and is associated with the resistance of the greater part of pipes to stress corrosion damageability. This issue is directly related to forecasting of the further development of stress corrosion damageability both for gas pipelines in which SCC has already been detected and for segments in which SCC problems have not yet arisen. An especially pressing task is assessing the possibility of the development of SCC in process pipelines of compressor stations situated in regions where the presence of the SCC process on linear segments has been identified, because equipment operation and the presence of maintenance staff on the station territory involve increased risk.