Time of Flight Diffraction Transducers

Features All TOFD transducers are highly damped with short pulse length, broad bandwidth and high sensitivity, utilising lead metaniobate crystals. There are four different waves involved in a TOFD image: A longitudinal wave generated by the transmitter and partially transformed into a spherical wave when the beam crosses the tip of the defect. The lateral wave that flows on the surface between the two transducers. The longitudinal wave reflected by the back wall. The shear waves generated by the mode conversion L/T on the interface of discontinuities.

20mm	12mm	6mm

Frequent Applications

One of the major applications of TOFD is the ultrasonic examination of welds after final heat treatment and/or hydraulic testing, to verify the absence of cracks not detectable by radiography and to prove conformity with prior ultrasonic manual examination carried out during construction.

Another current application of TOFD is its use in monitoring welds during the service life of components. Stored data acquired from initial examinations, made during the final stage of construction, can be compared with new data obtained from in-service inspection.

Transducers

Wedges

Code	Crystal Diameter (mm)	Frequency	Wedge Dimensions
			A	B	C
TFW6-XX	6	2, 5, 10	20	24	17
TFW12-XX	12	2, 5, 10	25	36	25
TFW20-XX	20	2, 5 35	35	40	35
Where XX equals the angle required