L51443 Evaluation of Flaw-Depth Measurement Accuracy Using Ultrasonic Inspection Techniques

The objectives of this project were to: 1) Establish the accuracies of four ultrasonic flaw-sizing techniques; and 2) Provide a direction for future work in the transfer of flaw-characterization technique(s) from the laboratory to field use. The four ultrasonic techniques for sizing flaws in pipeline girth welds were evaluated against a set of seventeen girth-weld flaws that included cracks, incomplete fusions, inadequate penetrations, slag inclusions, a gas pocket and a porosity. The correlations were poor for the results obtained by two versions of the decibel-drop technique. The best results were obtained from the supplemented satellite-pulse observation technique.