What is non-destructive testing?

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NDT is the abbreviation for Non-destructive testing. NDT refers to a testing method applied to materials or workpieces that does not damage them or affect their performance or usability in the future. By using NDT, it is possible to detect defects present inside and on the surface of materials or workpieces, to measure their geometric characteristics and dimensions, and to determine the internal composition, structure, physical properties, and state of the materials or workpieces. NDT can be applied in various areas such as product design, material selection, manufacturing, final product inspection, and in-service inspection (maintenance), playing a key role in optimizing quality control and reducing costs. NDT also helps to ensure the safe operation and/or effective use of products. NDT encompasses a variety of methods that can be effectively applied, with the most commonly used NDT methods being: radiographic testing, ultrasonic testing, eddy current testing, magnetic particle testing, penetrant testing, visual inspection, leak detection, acoustic emission testing, and fluoroscopic testing. Since various NDT methods each have their own scope of application and limitations, new NDT methods are continuously being developed and applied. Generally, as long as it meets the basic definition of NDT, any physical, chemical, or other possible technical method can be developed into an NDT method. In our country, the term \"non-destructive testing\" was initially referred to as \"flaw detection\" or \"non-destructive flaw detection.\" The various methods used for this purpose were also called flaw detection methods, such as radiographic testing, ultrasonic testing, magnetic particle testing, penetrant testing, and so on. This term or notation has been widely spread and is still in use to this day; its frequency of use is no less than that of the term \"non-destructive testing\". Abroad, the English term corresponding to the phrase \"non-destructive testing\" is mostly identical in its first part, that is, the word \"non-destructive\", but the spelling of its second part varies. In Japan, it is commonly written as \"inspection\"; in many European countries, it was previously written as \"flaw detection\", but now \"testing\" is used uniformly. In the United States, in addition to \"testing\", terms such as \"examination\" and \"evaluation\" seem to be preferred. When combined with the first part, the abbreviations formed from these words are NDI, NDT, and NDE; in Chinese, they are translated as various terms such as non-destructive testing, non-destructive inspection (non-destructive examination), non-destructive inspection, non-destructive testing, and non-destructive evaluation. In fact, these different English terms and their corresponding Chinese terms have the same meaning; they are synonyms. To this end, the International Organization for Standardization’s Technical Committee on Non-Destructive Testing (ISO/TC 135) developed and issued a new international standard (ISO/TS 18173:2005) aimed at standardizing these terms in their various forms and spellings, clarifying that they refer to the same concept and are synonyms, all equivalent to non-destructive testing. Different ways of writing are simply due to differences in linguistic habits. Therefore, as a standardized term, the use of “non-destructive testing” is recommended, with the corresponding English term being “Non-destructive testing”. For the names of various non-destructive testing methods, it is also recommended to use the term “testing”, such as radiographic testing, ultrasonic testing, magnetic particle testing, penetrant testing, eddy current testing, and so on. When translating, English terms such as inspection, examination, and evaluation that are used in conjunction with Non-destructive should all be translated as “non-destructive testing”; efforts should be made to avoid using expressions like “non-destructive flaw detection,” “non-destructive inspection,” “non-destructive examination,” or “non-destructive evaluation.” This translation method is also applicable to the translation of names of various non-destructive testing methods. Note: Terms such as inspection, examination, and evaluation are recommended to be translated as “inspection” only when translating the names of non-destructive testing methods; in other cases, they should be translated according to the content of the original text and common Chinese usage. English names and abbreviations of common NDT methods: Ultrasonic testing – UT; Magnetic particle testing – MT; Computed tomographic testing – CT; Visual testing – VT; Radiographic testing – RT; Penetrant testing – PT; Acoustic emission testing – AT/AE; Eddy current testing – ET; Leak testing – LT