Liquid penetration testing refers to the use of highly permeable liquids to penetrate the surface defects of components, and then try to make them show defects, which is a non-destructive testing method for surface defects. According to the different permeate used, it can be divided into color permeation method and fluorescent permeation method. When coloring and penetrating, spray a layer of colored penetrating liquid on the surface of the cleaned component. After the penetrating liquid penetrates into the defect, the surface color liquid is washed away. Then a layer of display agent is sprayed on, and the color liquid that has penetrated into the defect then penetrates into the display agent to show the defect.
