Non Destructive Testing Liquid Penetrant. Liquid penetrant inspection methods are used to check nonporous materials for defects open to the surface and surface defects can be found with penetrant inspection. It can change invisible defects to visible defect by using liquid dye.
In liquid penetrant, the test object or material is coated with a visible or fluorescent dye solution. Ndt liquid penetrant testing or dye penetrant inspection (dpi) is used to locate surface material defects through the application of a die penetrant and developer powder. Its popularity can be attributed to two main factors, which are its relative ease of use and its flexibility.