Ultrasonic Testing (UT) uses short ultrasonic waves with frequencies higher than the human ear can hear.
Frequencies are typically in the range of 500 KHz to 20 MHz and are used for detecting discontinuities. Pulses penetrate the material to identify internal flaws or provide material characterization.
A probe sends a sound wave into a test material. There are two indications, one from the initial pulse of the probe, and the second due to the back wall echo. A defect creates a third indication and simultaneously reduces the amplitude of the back wall indication. The depth of the defect is determined by the ratio D/Ep.
Types of flaws that can be detected with UT
UT can be helpful in identifying discontinuities such as hidden porosity, inclusions, voids, and cracks in a material.
Types of material that can be tested using UT
Most commonly Ultrasonic Testing is used on steel and various metals and alloys. This technology is also widely used in the medical industry.
Advantages of UT
There are many positive aspects to using UT a few key points include:
- Ultrasonic Testing is Non Destructive, material will not need to be sectioned, cut, altered or exposed to chemicals
- There are no hazards to your health, unlike other methods that require the use radiation or chemicals
- When used correctly, the results are very reliable
- This method is typically less expensive than radiography
Disadvantages of UT
Although Ultrasonic Testing are a great tool, it is important to remember a few things:
- Extensive technical knowledge, training and specialized equipment are required to perform this method
- Inspection of certain geometries can be very challenging
- Machines and gages must be calibrated
Industries that use UT
UT can be used in many industries including:
- Oil and Gas
- Power Generation