What is Non-Destructive Testing?

What is Non-Destructive Testing?
8/16/2013 4:22:34 PM

Non-destructive testing (NDT) is a great industry to be in, as it's a very complex and wide-ranging field.

As such, the precise definition of NDT is generally very long, extremely complex – and quite frankly confusing for many people.

It doesn't have to be that way! Here’s a shorter, simplified version of the definition: Non-destructive testing is a method of testing materials for structural integrity without destroying or damaging the material.

What is Non-Destructive Testing?

The advantage of non-destructive testing over other methods is that the material or component being tested – for example, a pipe weld – can still be utilized after testing is completed.


While non-destructive testing is most commonly utilized in the industrial sector to test metal materials such as oil & gas pipelines and various metal machinery components, it also has applications in everything from engineering to medicine and various scientific fields. However, for the purposes of this discussion, we will focus on the industrial applications of non-destructive testing.


Oil & gas companies and various other industrial businesses use non-destructive testing to help ensure that metal materials that are subjected to high loads or high pressure will not fail due to defects, flaws or wear. A perfect example of a defect is a crack in a pipeline weld. Non-destructive testing can allow the defect to be detected and repaired before the pipeline fails – thus potentially averting a dangerous and costly situation.


There are four major methods of non-destructive testing including ultrasonic testing, radiography, magnetic particle testing and liquid penetrant testing. These methods may be utilized to test virtually anything made of metal.


Ultrasonic testing (UT) is a non-destructive testing technique that utilizes high-frequency sound waves to detect imperfections in metal materials, as well as changes in properties within the materials that could cause problems or failure of the component being tested.


Radiography testing (RT) is a non-destructive testing technique that utilizes x-rays or radioactive isotopes to test metal materials – much the same way that doctors analyze "x-ray images” taken of their patients.


Magnetic particle testing (MT) is a non-destructive testing technique utilized to detect defects (such as cracks) at or near the surface in metals. This technique utilizes a magnetic field, combined with the application of fine magnetic particles (similar to iron shavings) to reveal defects.


Liquid penetrant testing (LT) is a non-destructive testing technique where the material being tested is coated with a liquid dye solution (sometimes fluorescent dye is used). The dye is then removed and a developer is applied – which acts to "draw” the dye out of any defects present, allowing the defect to be seen easily.


Non-destructive testing techniques are particularly useful in the industrial sector as a cost-effective way to evaluate the integrity of metal materials and equipment. In many instances, older materials and bonding methods are still in active use – particularly in the oil & gas industry. With non-destructive testing, companies are able to help ensure that these materials can continue to be utilized safely – reducing the likelihood of structural failure and potential accidents. As such, non-destructive testing often plays a critical role in both quality control and safety for many industrial businesses.


Tech Service Products is a leading distributor of non-destructive testing products and industrial supplies.

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