Ultrasonic Testing

Ultrasonic testing (UT) is a form of Non-destructive Testing (NDT) that uses very short ultrasonic sound waves to conduct examinations and make measurements. These short ultrasonic sound waves are directed into materials to detect any evidence of cracks, corrosion, or other hidden internal faults.

The UT method of application first involves preparing the material for testing by cleaning it of oil and other contaminates. An ultrasound transducer is then connected to the UT diagnostic machine and passed over the material being examined. From this point there are two methods of receiving the ultrasound sound wave.

The first uses a pulse-echo mode, where the transducer sends and receives the pulsed waves as a “sound” reflected back into the machine, and the distance and arrival time is then measured. The second uses through-transmission mode, where the transducer sends ultrasound through one surface and a separate receiver detects the amount that has reached it on another surface after travelling through the material. Cracks, corrosion and other hidden faults between the transducer and receiver reduce the amount of sound being transmitted, thus highlighting their presence.

The main advantage of using UT is because of its non-destructive nature, which means the material being tested doesn’t need to be cut or exposed to chemicals to be tested. Other advantages include its sensitivity, being able to identify the tiniest faults, and only one side needs to be accessed during testing. UT is most commonly performed on steel and other metals, but can also be used on concrete, wood, ceramics and plastics. This form of testing is used in many industries, including automotive, aerospace and locomotive.