Ultrasonic Testing, also known as UT, is a method of characterizing the thickness or internal structure of a test piece through the use of high frequency sound waves.

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UT utilises transmission of very high-frequency sound waves into a material to detect discontinuities or to locate changes in material properties.

 

The most commonly used ultrasonic testing technique is pulse echo, wherein sound is introduced into a test object and reflections (echoes) are returned to a receiver from internal discontinuities or from the part's geometrical surfaces.

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Ultrasonic Inspection is a very useful and versatile NDT method. Some of the advantages of ultrasonic inspection that are often cited include:

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• It is sensitive to both surface and subsurface discontinuities.

• The depth of penetration for flaw detection or measurement is superior to other NDT methods.

• Only single-sided access is needed when the pulse-echo technique is used.

• It is highly accurate in determining reflector position and estimating size and shape.

• Minimal part preparation is required.

• Electronic equipment provides instantaneous results.

• Detailed images can be produced with automated systems.

• It has other uses, such as thickness measurement, in addition to flaw detection.

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