TIME OF FLIGHT DIFFRACTION

TOFD is another advancement in Ultrasonics and IRC Engineering is the only company presently in the Northern Part of India to have procured it. In a TOFD system, a pair of ultrasonic probes sits on opposite sides of a weld. One of the probes, the transmitter, emits an ultrasonic pulse that is picked up by the probe on the other side, the receiver. In undamaged pipes, the signals picked up by the receiver probe are from two waves: one that travels along the surface and one that reflects off the far wall. When a crack is present, there is a diffraction of the ultrasonic wave from the tip(s) of the crack. Using the measured time of flight of the pulse, the depth of a crack tip can be calculated automatically by simple trigonometry. This method is even more reliable than traditional radiographic, pulse echo manual and automated weld testing methods. IRC Engineering has PCN and ASNT NDT LEVEL-II experts who can perform these specialised tests. TOFD has been widely used due to its capability of getting accurate results of defect size.

Advantages

1. Results obtained are digital and can be stored for life time period.
2. Defect Sizing is highly accurate and thus the system can be used to carry out Fitness For Service and Residual Life Assessment.
3. Due to exact defect sizing, Acceptance and Rejection of flaw is possible during erection activities.
4. No Radiation Hazard.
5. Erection activities can be performed in parallel with inspection activities.