A metrological based realization of Time-of-Flight Diffraction technique

Time-of-Flight Diffraction (ToFD) is a technique of non-destructive testing by ultrasound used for detecting faults and discontinuities in different components. The development and implementation of this technique was based on ISO 16828: 2012 (Non-Destructive testing - Ultrasonic Testing - Time-of-Flight Diffraction Technique as a method for Detection and Sizing of Discontinuities). Controlling the different characteristics of the system, from the specification of the ultrasonic characteristics, to the imaging technique, was possible to identify the sources of uncertainty and estimate the ToFD measurement uncertainty. For a 25 mm deep stainless steel test object, expanded uncertainties less than 0.5% (0.093 mm) was achieved with ToFD. For larger ultrasonic paths, the technique is able to depict even lower uncertainties, regarding some care are taken in the ultrasonic measurement setup. (C) 2015 The Authors. Published by Elsevier B.V.