Ultrasonic Non-destructive testing, also known as ultrasonic Testing or simply UT, is a method of characterizing the thickness or internal structure of a test piece through the use of high frequency sound waves. The frequencies, or pitch, used for ultrasonic testing are many times higher than the limit of human hearing, most commonly in the range from 500 KHz to 20 MHz.
Ultrasonic inspection can be used for flaw detection/valuation, dimensional measurements, material characterization, and more. A common example is ultrasonic thickness measurement, which tests the thickness of the test object, for example, to monitor pipe work corrosion.
Ultrasonic testing is often performed on steel and other metals and alloys, though it can also be used on concrete, wood and composites, albeit with less resolution. It is a form of non-destructive testing used in many industries including aerospace, automotive ,Power and other Oil and Gas sectors.
Detecting flaws early on is of utmost importance. But you don't want the process to be time consuming or costly.