Identification of flaw signals in the angle beam ultrasonic testing of welded joints with geometric reflectors

Abstract

The identification of flaw signals in ultrasonic testing of welded joints is quite often very difficult in the angle beam testing of welded joints due to the presence of geometric reflectors, such as weld roots and counter bores, generating non-relevant signals. This paper describes a new approach to perform the flaw identification in such a problematic situation. This approach involves four steps: 1) acquisition of “reference” signals for both flaws and geometric reflectors, 2) normalizing both reference signals and testing signals, 3) deconvolution of angle beam testing signals by references, and 4) discrimination of flaw signals from geometric reflections by means of the patterns of deconvolution results. As results, proposed technique has a great potential to identify similar signal, especially to distinguish notch signals from the geometric reflections. The similarity function has narrow width in time domain, and could improve accuracy in time of flight.