Knowing what technique to use, when and how are the trademarks of a successful NDT technician.
That’s why NDT Classroom's online courses focus on ensuring students fully understand different applications of techniques and how and when to implement them. For example, let’s look at the pulse echo technique (also known as reflection), which the following image demonstrates:
This image is an example of a standard compression wave technique reflecting sound from the back wall or discontinuities. The image is used to assess the integrity of the test material for service. In order to obtain a reflection, it is necessary for the reflector to be oriented so that part of its surface is parallel to the scanning surface, otherwise known as 'normal' to the beam. Laminar discontinuities and volumetric discontinuities like gas pores and nonmetallic inclusions are all suitably orientated. However, discontinuities that are angled to the scanning surface may not reflect at all or may reflect the sound away from the transducer.