Ultrasounds in NDT are very close to medical ultrasonics used for echography. Mostly, we use yhe same word « echography » in non destructive testing. It uses to be a transducer, sending an ultrasonic wave inside the material to be inspected. This material can be metallic, plastic, composite, ceramic. Then, the same transducer will catch any signal coming from the part and any inside discontinuities such as cracks, porosities, inclusions, delaminates… This method is able to detect and to locate internal defects. This is the reason why ultrasonic inspection is a volumic method against penetrant testing, magnetic particle inspection or eddy current which are only able to detect surface defects. Ultrasonic inspection can be used in manual inspection or automatic using only one side ces, even for large parts or components or for long parts. At the opposite of radiography, ultrasonic inspection doesn’t have risk for security and health.
Ultrasonic inspection request a quite high level of technicity and knowledge for inspectors, but new technologies are emerging such as TOFD or Phased Array which are simplifying detection and analysis.