Nondestructive testing is a form of materials testing used when the materials being examined cannot be destroyed in the process of testing. This type of testing is used when permanently changing the material during testing is not an option for any number of reasons from safety to expense. In some cases, it may reveal the need for more thorough testing methods, some of which could cause permanent alteration or damage. Turning to nondestructive testing first can save money and increase efficiency on a project.
In nondestructive testing, a large array of techniques are available for evaluating a material without changing it. Imaging studies are a common technique. X-ray and other imaging methods allow people to look inside a material for issues like cracks and flaws without causing any damage. Ultrasound is another popular technique for both imaging and stress testing, as changes in the sound waves can reveal changes in the integrity of the object being tested, highlighting issues like bubbles and fractures inside the material.
People can also use techniques like covering something in a penetrant and then imaging it. If the material is sound, the penetrant will lie on the surface. If there are cracks, holes, and other issues, it can seep inside, spreading through the material. This will not endanger the substance, and the penetrant can be easily removed after testing. Nondestructive testing also includes standard activities like weighing and measuring the material, collecting information about how light refracts off it, and using chemical sniffing to learn more about its composition.
At the conclusion of nondestructive testing, a detailed report will be generated to provide information about the material being studied. This report can be used for anything from forensic testimony in court about the circumstances of an accident to supporting documentation for a manufacturer's patent application for a newly developed material. The documentation will discuss any flaws or shortcomings in the testing so someone evaluating the results of the test can identify areas of concern.
Numerous firms offer nondestructive testing of materials, for fees that vary, depending on the nature of the material and how much testing is required. Some companies perform their own testing in-house first and may start with nondestructive methods to collect basic information without needing to destroy the objects they are testing. Generally, people who plan to use nondestructive test results to support applications for government approval, cases in court, or other legal matters will need testing performed by a non-biased third party.