Time of Flight Diffraction- An Alternate Non-Destructive Testing Procedure to Replace Traditional Methods

Time-of-flight-diffraction Technique (TOFD) is considered as one of the fastest methods of Non-destructive testing (NDT) since a weld can be characterized to a certain degree with one single scan along its length with two probes. An image of the complete weld is created showing component and, more importantly, any defect information. In this paper a comprehensive review of the TOFD technique covering many aspects, e.g. accuracy, coverage, resolution, repeatability, and last not least speed where the real value of TOFD lies-despite its few inherent limitations is presented. This paper presents the results of experimental investigations carried out using various NDT techniques including TOFD on specimens such as welds with various types of defects. The results of these investigations are compared and the feasibility of using TOFD as an alternative NDT procedure to replace the traditional NDT methods of inspecting fabricated pressure vessel components are examined