L51685 Effect of Weld Metal Matching on Girth Weld Performance Volume II-Experimental Investigation

This is the second volume of a three-volume study (see also L51651 and L51711).

The integrity of girth weld defects in gas transmission pipelines is ensured by non-destructive inspection procedures. The acceptance level of pipe line girth weld defects revealed by non-destructive testing is commonly based on workmanship quality control. Unfortunately, workmanship defect acceptance levels are based on experience and are, by necessity, both arbitrary and often conservative.

This report presents the results of an experimental study of the failure behavior of 11.6 mm (0.457 in.) pipe segments taken from 36-inch diameter pipes with defects in the girth weld. Small-scale and fatigue pre-cracked, curved, wide-plate test specimens were used. The objectives were to: (1) determine the effect of pipe and weld metal yield strength differences on girth weld performance; (2) verify the assumption that the CTOD test is a reliable indicator of girth weld performance; and (3) evaluate the usefulness of the Charpy V-Notch test for predicting girth weld failures.