Showing papers on "Time-of-flight diffraction ultrasonics published in 1995"

Device for the non-destructive testing of hollow tubular objects by means of ultrasound

Abstract: A device for the non-destructive testing of hollow tubular objects using ultrasound. The device has a stage for transmission of ultrasonic waves and a stage for reception of ultrasonic signals. The transducer structure includes an assembly of annular individual transducers which are juxtaposed in a coaxial fashion or, in an alternative embodiment, two annular arrays, each of which consists of an assembly of juxtaposed individual transducers. Moreover, the stages for the transmission and reception can simultaneously select, from the assembly or from each of the assemblies, at least one transmitter transducer (2(I)) and at least one receiver transducer (2(j)). This selection forms a transducer sub-assembly which can be displaced at will by electronic scanning along the axis of the succession of transducers in order to enable optimum execution of the so-called TOFD testing method.

TOFD used to replace radiography

Abstract: During the construction of a refinery in the Rotterdam area, AEA Sonomatic has used the ultrasonic Time-Of-Flight Diffraction (TOFD) technique on a large scale as an alternative to radiography. The use of the technique resulted in major cost savings and increased confidence in the end-product.

High-accuracy defect sizing for CRDM penetration adapters using the ultrasonic TOFD technique

Abstract: Ultrasonic time-of-flight diffraction (TOFD) is the preferred technique for critical sizing of throughwall orientated defects in a wide range of components, primarily because it is intrinsically more accurate than amplitude-based techniques. For the same reason, TOFD is the preferred technique for sizing the cracks in control rod drive mechanism (CRDM) penetration adapters, which have been the subject of much recent attention. Once the considerable problem of restricted access for the UT probes has been overcome, this inspection lends itself to very high accuracy defect sizing using TOFD. In qualification trials under industrial conditions, depth sizing to an accuracy of {<=} 0.5 mm has been routinely achieved throughout the full wall thickness (16 mm) of the penetration adapters, using only a single probe pair and without recourse to signal processing. (author).