RESIDUAL STRESS IN GIRTH WELDS: SEEING MEASUREMENT DATA DIFFERENTLY

This paper studies some of the recent residual stress measurement data on pipeline girth welds, which are available in the open literature, using a statistical approach. The measurement data points from residual stresses profiles are separated into three different zones, ie, outer zone, inner zone and middle zone, to study their distributions statistically. This statistical analysis indicates that for the region close to the outer surface, where welding is most likely to produce critical flaws, most of the reported measurement data points lie below the yield strength of the base metal. The paper concludes by presenting a case study using deterministic and probabilistic fracture analyses and providing some recommendations for further improvement of the relevant codes and standards.