Disadvantages: low sensitivity, limited to surface defects, requiring smooth surface, unable to detect depth.
Color flaw detection is a nondestructive testing method and a surface testing method. It is mainly used to detect surface damage such as cracks that can't be recognized by naked eyes, such as near-surface defects (cracks), pores, delamination, incomplete penetration and incomplete fusion of stainless steel materials (also called PT detection). It is suitable for inspecting dense metallic materials (welds), nonmetallic materials (glass, ceramics, fluoroplastics) and defects (cracks, pores, etc.). ) on the surface of the product.
Basic principle of color flaw detection;
Paint colorant on the surface of the material, and the colorant permeates into the damaged part. After standing for a period of time, the colorant on the surface is washed away. Apply developer to the cleaned surface, and the damaged part can be seen clearly because the colorant has penetrated.
Capillary phenomenon mainly uses capillary phenomenon to make penetrant penetrate into defects, removes surface penetrant with cleaning agent, and leaves penetrant in defects, and then uses capillary action of developer to adsorb residual penetrant in defects, so as to achieve the purpose of inspecting defects.