What Is Ultrasonic Testing?

What is Ultrasonic Testing?

Ultrasonic testing is a form of nondestructive testing that uses sound waves to evaluate the mechanical properties of materials. 

The term ultrasonics is often used to describe this family of techniques, although it is more accurate to refer to them as ultrasonic testing.

Ultrasonic testing is used to characterize the material being tested and detect flaws within the material. It can be used as a non-destructive test (NDT) technique for determining the thickness of materials and measuring internal flaws such as cracks. 

Ultrasonic testing can be used with other NDT techniques such as magnetic resonance (MR), infrared (IR), and x-ray testing.

Ultrasonic testing is used in many industries, including:

  • Steel and metal construction
  • Metallurgy
  • Manufacturing
  • Aerospace industrial applications and more

What’s the Application of Ultrasonic Testing?

The ultrasound pulses excite the flaws or cracks and measure the time taken to emit the sound waves, known as the ‘time of flight.’ This can be used to determine the size of the flaw or crack and hence its impact on performance.

Ultrasonic testing is used in metallurgy and manufacturing industries to determine the size of internal flaws or cracks within a material before being used in production. This is done by measuring the time for an ultrasonic pulse to travel through a material and then comparing it with an outstanding value of 0.9mm (at 10MHz).

Ultrasonic testing is also called acoustic emission (AE) testing, which uses ultrasonic vibrations to measure the thickness, density, hardness, and elastic modulus of materials such as metals, ceramics, concrete, etc. 

Ultrasonic testing is used in the automotive industry for measuring the thickness of metals in vehicles to ensure that they are not thinner than specified. The thickness measurement is made by transmitting ultrasonic pulses through a strip of material, measuring the time taken for them to travel.

Ultrasonic testing is used to measure the thickness of pipes, tubes, cylinders, channels, etc., to monitor steel pipes and tubing corrosion. This is done by transmitting ultrasonic pulses through a pipe or tube at different frequencies and measuring the time for an ultrasonic pulse to travel through a pipe or tube at each frequency. 

Ultrasonic testing is performed on composite materials to evaluate their mechanical properties. The test material is placed in the ultrasonic transducer. The ultrasonic signal is then used to excite the composite material, emitting a sound wave that travels through the material and returns to the transducer as an echo. The time taken for this sound wave to return determines the density of the material and hence its stiffness or strength.

What’s the Advantage of Ultrasonic Testing?

1. Low Cost

Ultrasonic testing is an inexpensive test method to determine the quality and integrity of steel materials.

2. Convenient

Ultrasonic testing can be done in any location and by anyone who has a small ultrasonic transducer (UT) or hand-held probe unit. 

This makes it very simple to perform on-site inspections of steel or other materials from inside the material, or from outside the material, for example, on pipelines, ships, or bridges. 

It is also possible to inspect sheet metal parts by using a hand-held probe unit placed in contact with the material being inspected.

3. Quick

Ultrasonic testing can be completed within seconds at high speed, making it suitable to inspect large numbers of parts continuously in operation over long periods, such as in factories where products are being manufactured continuously. 

More rapid measurements are possible using modern digital signal processing techniques that reduce the time required for measurement by orders of magnitude.

4. Accurate

Ultrasonic testing provides high-accuracy measurements, which are accurate to plus or minus 0.001 inches. 

It is possible to perform measurements of thickness and composition at a resolution of 0.01 inch or better, which makes it possible to detect minute flaws within the material being tested.

5. No Risk Of Harm

Ultrasonic testing does not involve any physical contact with the tested materials, so there is no danger of damage to the material being inspected or any risk that a falling object may injure an operator during testing. 

This greatly reduces the risk of damage to equipment and people from accidental contact during construction, maintenance, and repair work on steel structures exposed to windstorms, earthquakes, or other hazards.

NDT-KITS is the world’s leading manufacturer of ultrasonic testing and inspection equipment. Established in 1988, it is a high-tech enterprise that has been devoted to developing and manufacturing ultrasonic testing and inspection equipment for more than 20 years. 


The application of ultrasonic testing is quite broad, and the technique can be used to detect flaws in steel, concrete, composites, wood, and other materials. It is also used in the mechanical industry to check the quality of metal components.

Ultrasonic testing can be beneficial to find out the thickness of pipes, wires, and other metals or other materials. It can also be used for many other purposes, such as checking cracks and corrosion on pipelines, measuring the thickness of metal sheets for heat-treating purposes, etc.

If you would like to learn more about Ultrasonic Testing or speak with one of our experts, don’t hesitate to get in touch with us at + 852 3078 0889 or email us at sales@ndt-kits.com.

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