Applicability of different artificial defects in qualification of ultrasonic testing method

Ultrasonic properties of real stress corrosion cracks and artificially produced defects were examined in a comparative round robin exercise. Seventeen professional ultrasonic testing (UT) examiners inspected eleven different defects. Detection and sizing results together with opinions about applicability of different reflector types were collected. The information was recorded to assess the detectability and sizing accuracy of reflectors and some insight was obtained on the indication features that inspectors use to examine the reflector properties. Reflector properties that are typical for real defects were identified. The most important reflector characteristics were the stagger/specular of surface, echo dynamics generated and the influence of probe rotation (skew angle variation). It can be considered that the ultrasonic aspect is dominant and the geometric appearance of an artificial reflector does not need necessarily to be similar with the real defect. (orig.)