Influence of near-field on the TCG calibration of phased array ultrasonic testing

In international and domestic standards of phased array ultrasonic testing for welded joints, Time-corrected gain (TCG) calibration are usually required or recommended to be used to compensate the sensitivity of reflectors at different depths, so as to ensure the accuracy of detection result. At the same time, in the corresponding phased array ultrasonic acceptance standard, the acceptance method based on the amplitude and length is mostly adopted, so the accuracy of TCG calibration is the basis of phased array ultrasonic detection application, its importance is self-evident. In this paper, the influence of near field on phased array ultrasonic TCG calibration is analyzed through calculation and comparative test. The research results can provide reference for the selection of probe and wedge and the setting of parameters in phased array ultrasonic testing.