Accurate sizing
Flaw height is measured from the diffracted tip signals, independently of the flaw’s orientation and reflectivity.
Time of Flight Diffraction (TOFD)
Time of Flight Diffraction (TOFD) testing of welds for accurate flaw height sizing, by operators certified to ISO 9712 Level 2 and Level 3.
Time of Flight Diffraction
Precise sizing of flaw height
TOFD uses two probes placed on either side of the weld, one transmitting and one receiving. Instead of relying on the amplitude of a reflection, it measures the time of flight of the signals diffracted from the tips of a flaw, which gives an accurate measurement of the flaw’s through-wall height.
- TOFD testing of welds
- Operators certified to ISO 9712 Level 2 and Level 3
- Recorded scans for review and documentation
- Reporting against the acceptance criteria of the project
Why TOFD
Strengths and limits
Fast scanning
The whole weld volume is covered in a single scan along the weld, with a permanent record of the results.
Combined with PAUT
TOFD has limited coverage close to the surfaces, so it is often combined with phased array. Its use on welds is described in ISO 10863.
Related methods
Often combined with
Phased array (PAUT)
Imaging of the weld, including the near-surface zones.
Learn moreAutomated UT (AUT)
TOFD and PAUT on a mechanised scanner.
Learn moreInspection & QC
NDT as part of the complete inspection plan.
Learn moreNeed TOFD on your welds?
Tell us the material, the wall thickness and the acceptance standard.