What is nondestructive testing (NDT)?

Nondestructive testing(NDT) is a testing method to check the surface and internal quality of the inspected parts on the premise of not damaging the working state of the workpiece or raw materials.


The commonly used nondestructive testing methods are: X-ray inspection, ultrasonic testing, magnetic particle testing, penetrant testing, eddy current testing, gamma ray testing, fluorescent testing, dye testing and so on.

Magnetic particle testing for large diameter elbow welds

Magnetic particle testing for large diameter elbow welds


Through the detection of the internal defects of the product, the product is improved from the following aspects

  1. Improve manufacturing process;
  2. Reduce manufacturing cost;
  3. Improve the reliability of products;
  4. Ensure the safe operation of the equipment.


Nondestructive testing is to use the sound, light, magnetic and electrical properties of the material to detect whether there are defects or non-uniformity in the tested object, and give the size, location, nature and quantity of defects on the premise of not damaging or affecting the performance of the tested object. Compared with destructive testing, nondestructive testing has the following characteristics. The first is non-destructive, because it will not damage the performance of the object to be tested; the second is comprehensive, because the detection is non-destructive, it can be 100% comprehensive detection of the tested object when necessary, which is impossible by destructive detection; the third is full-scale, destructive detection is generally only applicable to the detection of raw materials, such as machinists Generally used in the process of tension, compression, bending, destructive inspection is for the manufacturing of raw materials, for finished products and articles in use, unless they are not ready to continue service, otherwise destructive testing can not be carried out, and non-destructive testing will not damage the performance of the object to be tested. Therefore, it can not only be used for manufacturing raw materials, intermediate process links, until the final product for the whole process testing, but also for the equipment in service.

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