Time of flight diffraction (TOFD) inspection is an ultrasonic inspection that can locate and size defects in welds and other components. This method is commonly performed on welds and weld overlays, piping, pressure vessels, clad material, storage tanks, and structural steel. Heavy wall vessels and piping can be thoroughly assessed for fabrication flaws with TOFD.
TOFD can be combined with pulse-echo (angle) techniques to improve data reliability, probability of detection, and accuracy of sizing. The TOFD and pulse echo probes are attached to a scanner simultaneously. Line scans are performed parallel to the weld direction.
