Circumferential SCC in Pipeline Due to Land Creeping

This paper describes the analyses performed in a circumferential rupture that occurred in a pipeline crossing a high slope region in the Southern part of Brazil. The pipeline was made of API 5L-X46 steel, coal tar coated, and has been in operation since 1977. The failure occurred after a period of heavy rains and was clearly associated to land creeping. The fracture occurred in parent metal 2770 mm away from the nearest circumferential welding. This fracture initiated in an approximately 3×70 mm external surface crack. Besides, several secondary parallel cracks were detected at a 6 o’clock position.