Main features of Ultrasonic Inspection:

Surface and slight sub-surface detection

This detection method uses high frequency sound waves, typically above 2MHz to pass through a material

A probe is used which contains a piezo electric crystal to transmit and receive ultrasonic pulses and display the signals on a cathode ray tube or digital display

The actual display relates to the time taken for the ultrasonic pulses to travel the distance to the interface and back

An interface could be the back of a plate material or a defect

For ultrasound to enter a material a couplant must be introduced between the probe and specimen


Rapid results

Both surface and sub-surface detection


Capable of measuring the depth of defects

May be battery powered



Trained and skilled operator required

Requires high operator skill

Good surface finish required

Defect identification & No permanent record

Couplant may contaminate & Calibration required

Ferritic Material (Mostly)