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Time-of-Flight Diffraction (ToFD)

Inspect welds and base materials without interrupting production

What is time-of-flight diffraction ultrasonic testing?

Time-of-flight diffraction (or ToFD) ultrasonic testing is a multi-mode ultrasonic inspection technique that measures the flight time of the sound energy through the material under inspection, from one probe to another. ToFD ultrasonic inspection is typically used to inspect welds up to 300mm thick and base material for flaws, cracks, root erosion, corrosion and cladding conditions. It can completely cover a typical butt weld, the heat-affected zone (HAZ) and the base material adjacent to the weld from a single position.

ToFD ultrasonic testing is typically conducted in accordance with the requirements of ISO 10863, “Non-destructive testing of welds—Ultrasonic testing—Use of time-of-flight diffraction technique (TOFD).” Extensive experience in the use of the ToFD technique is generally required to accurately evaluate the results produced by ToFD ultrasonic testing.

What are the advantages of ToFD ultrasonic testing?

ToFD ultrasonic inspection can be performed in less time than a manual ultrasonic inspection, and can more accurately evaluate the through-wall dimension of defects. ToFD inspection devices can also produce an image that can be archived for repeat inspection, as a tool for ongoing monitoring of an identified ndefect. Perhaps most important, a ToFD inspection does not interrupt production compared to other radiographic inspection techniques.

Why use TÜV SÜD for your ToFD ultrasonic testing requirements?

TÜV SÜD Chemical Oil and Gas is a leading provider of advanced nondestructive testing services, including ToFD ultrasonic testing. TÜV SÜD personnel have extensive training and experience in the use of ToFD ultrasonic testing in a wide range of industrial environments and consistent with the requirements of ISO 10863. In addition, our inspectors are certified to the Level II and Level III requirements of the American Society of Nondestructive Testing (ASNT).


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