Time of Flight Diffraction (TOFD)

SNS is an experienced provider of TOFD ultrasonic testing as both a standalone inspection method or in conjunction with PAUT for comprehensive weld examination programs. This technology is offered in both manual scanning formats as well as in multi-channel mechanized AUT systems.

TOFD is a highly reliable and accurate testing method for pipe weld examinations, in particular crack detection and sizing (depth), as it is very sensitive to defects located near the ID and OD surfaces of piping. TOFD measures the time of flight of an ultrasonic pulse to determine the position of a reflection. It also uses tip diffraction techniques to determine the size and/or depth of the defect and its acceptability to the applicable code.

TOFD is a versatile NDT technology with a variety of applications, including fast and efficient crack sizing and rapid scans of pipeline long seam welds as well as circumferential butt welds. TOFD is typically complemented by conventional or phased array ultrasonic testing methods.