Ultrasonic Wall Thickness Testing (WT) or sometimes referred to as Ultrasonic Wall Thickness Measurement (UTM) is a limited form of Ultrasonic Testing (UT) in which ultrasonic sound waves are used to gauge the thickness of different materials.

 

Using a straight beam (zero degree) ultrasonic transducer, high frequency sound waves are transmitted into the test object. These waves travel through the material at a fixed velocity and are reflected by the back surface of the material back to the transducer.

 

The transducer receives the reflected sound wave and converts the amount of time taken by the ultrasound wave to return to the surface to a displayed UNIT usually in millimeters relating to the thickness of the material under test.

 

This type of measurement is typically performed with an ultrasonic thickness gauge.