Realistic Evaluation of the Height of an Infinite- Length Reflector Perpendicular to the Surface in T, X Welds with Ultrasound

The height of the unwelded root part in T and X welds whose length exceeds the sound-beam width at the contact point between the sound and the reflector can according to methods known today only be estimated by applying the tandem technique with two ultrasonic transverse probes from one single access area, or two access areas, the latter usually not possible in practice. However, with sheets having wide surfacing welds even one-surface access is not applicable due to angle probe dimensions and wide surfacing welds; therefore, an operator often uses a single miniature angle probe of 70 or 80° and the AVG method which uses a circular reflector as a reference for comparison, while the actual reflector is an infinite-length reflector inclined towards the direction of the sound beam axis. It therefore follows that the AVG method can in no way enable the estimation of the unwelded root height as the reflected sound wave completely fails to make contact with the receiving probe. Due to instances where the abovementioned welds were demolished in constructions, nearly causing death, we had to look for a more reliable method to control directed reflectors: the transformation of the longitudinal wave into a transverse wave.