Characterization and Interpretation of Ultrasonic Structural Echoes in Bimetallic Welds
Ultrasonic testings of bimetallic welds often show the presence of false calls. In pulseecho mode at oblique incidence, these false calls are detected close to the backwall. They are generally distributed along lines parallel to the buterrings. The phenomenon is disturbing because it limits the efficiency of ultrasonic testing in the area of the backwall: false calls can be misinterpreted for echoes from defects or they can mask the presence of real defects. If a defect is detected, they also limit the possibility of characterization.