Testing defects in automated ultrasonic testing and radiographic testing

For high-value pipeline projects, the NDT system used for weld inspection is frequently qualified by testing the system with flawed welds made deliberately for the purpose. Such deliberately fabricated flaws cannot be made to be completely realistic. Past work for pipeline inspection has shown a degree of tolerance to this when testing automated ultrasonic testing (AUT) systems, but this is not always the case. Comparing the shapes of the flaws from metallurgical sections with their ultrasonic detection suggests that shape is not the only determining factor and shows that ultrasonic testing (UT) diversity is key to a robust performance. Indeed, it is shown that a well-designed AUT system can be tolerant to a wide range of differences in materials, welding and geometry.