Fatigue Crack Growth Evaluation Of Pipeline Steels And Girth Welds

Abstract Fatigue test specimens were prepared and tested with an API 5 L X70 spiral welded pipe steel and girth weld. For a few selected specimens, two unloading compliance techniques (elastic compliance and back-face strain compliance) were applied simultaneously to a single specimen for direct comparisons of in situ crack size estimation. This paper also includes fatigue crack growth rate (FCGR) data of other pipe steels and welds available in the literature. It was observed that most FCGR curves of pipeline steels (X65–X100) remained within the BS 7910 mean and upper bound design curves in the Paris region. It was noted that the FCGR of austenitic stainless pipe steel and girth weld obtained from Arora et al. (2014), “Fatigue Crack Growth Studies on Narrow Gap Pipe Welds of Austenitic Stainless Steel Material,” Procedia Eng., 86, pp. 203–208) showed a very superior fatigue property.