Ultrasonic Testing - UT
UT is an NDT method that uses ultrasonic sound waves which are above the audible range of the human ear. Frequencies used range typically from 0.1 to 15 MHz. In UT there are 4 basic ways in which the sound waves propagate through the material that is being inspected. Those wave forms are:
As the ultrasonic sound waves enter the part they are reflected by the back surface or discontinuity and return back to the transducer. The returned sound waves are then converted into an electrical display as either an A-Scan, B-Sac, or C-Scan.
There are multiple techniques within UT. Most common is contact testing where a gel is used between the transducer and material surface to allow for the ultrasonic wave to enter the part. Another commonly used technique is one the utilizes water for sound waves to propagate into the part and is called immersion testing
Ultrasonic Testing can be done either manually, semi-automated, or automated. Some of the ultrasonic specialized equipment can include multiple transducers and scan presentations.