High-frequency sound waves are reflected if they hit any obstacle on their travelling path. Depending on the angle of impact, the reflected signal may or may not reach the receiving probe. The signal coming to the receiving probe is observed as an echo indication on the screen of the ultrasonic examination device. Thus, according to the position and height of the echo, the coordinates of the reflector in the inspection part can be calculated and it is possible to comment on the type of reflector.
Significant regional variations in sound velocity and sound attenuation characteristics within the test piece make it difficult to make an accurate assessment. In materials where the grain structure is coarse or where the sound attenuation is too high due to absorption, inspection may sometimes be impossible. To obtain accurate and reliable results, probes specially designed for the inspection surfaces should be used. Since the surface condition of the inspection part directly affects the inspection results, reference blocks are also required.
