Ultrasonic Testing (UT)

Ultrasonic testing (UT) is an NDT method that sends a high-frequency sound pulse into the steel through a coupled probe and times the echo: a back-wall echo gives wall thickness, and an earlier echo from a discontinuity gives flaw depth and size. It is the workhorse for hull thickness measurement at survey and for sizing planar weld defects, lack of fusion and cracks, that radiography can miss. Angle-beam, phased-array, and time-of-flight-diffraction variants extend it to complex weld geometry. Class welding rules set the UT extent and acceptance to ISO 11666 quality levels; thickness gauging follows ISO 16809. Calibration on a known reference block and a trained operator govern the result’s reliability.