Stress corrosion cracking poses a serious threat to aging underground cathodically protected gas pipelines. As coatings deteriorate, conditions conducive to both corrosion and stress corrosion cracking become more common. There have been many ruptures in various pipelines throughout the world attributed to SCC. One of the most important steps in combating failure by stress corrosion cracking is regular, reliable and cost effective monitoring of the pipelines. Current methods available (including hydrotesting and MT) are either expensive, time consuming, or not entirely reliable. Regular testing...
Stress corrosion cracking poses a serious threat to aging underground cathodically protected gas pipelines. As coatings deteriorate, conditions conducive to both corrosion and stress corrosion cracking become more common. There have been many ruptures in various pipelines throughout the world attributed to SCC. One of the most important steps in combating failure by stress corrosion cracking is regular, reliable and cost effective monitoring of the pipelines. Current methods available (including hydrotesting and MT) are either expensive, time consuming, or not entirely reliable. Regular testing of pipes would also improve understanding of stress corrosion cracking initiation and propagation. Field trials of a prototype remote control stress corrosion cracking (SCC) detection vehicle took place from the May 21st 1990 to the June 1st 1990, at Peterborough in South Australia, as part of an agreement with the Pipeline Research Committee, of the Pipeline Research Council International, Inc. The present vehicle is self-contained, battery powered and is controlled by an on board computer. The vehicle can operate in an evacuated line and maintains a telemetry radio link with a monitoring computer at the pipe entry position. The detection system consists of two piezoelectric ultrasonic wheel probes fired by dedicated electronics. The vehicle is programmed to move through a certain section of pipe to record areas of ultrasonic activity corresponding to SCC in the bottom section of the pipe.