It is used in the detection of planar and volumetric faults as well as crack type discontinuities in metallic materials.

High-frequency sound waves are produced by piezoelectric crystals in a piece called a “probe”.

As a general principle; High-frequency sound waves sent into the material are reflected if they hit an obstacle. Depending on the angle of impact, the receiver may or may not come to the probe. The location of the error can be determined by the coordinates of the reflected signal reaching the receiving probe on the screen of the ultrasonic inspection device. An interpretation of the size of the reflector is made by looking at the height of the echo.

Evaluation becomes difficult if the sound velocity and sound attenuation characteristics of the inspection piece show strong regional variations. In cases where the coarse grain structure and sound attenuation are too much, it is sometimes difficult to perform the examination.