The color penetrant inspection process is to spray or coat the penetrant containing pigments and phosphors on the surface of the inspected part of the weldment, and use the capillary action of the liquid to penetrate into the surface defects of the opening.Then, the permeate remaining on the surface is removed, and after drying, a developer is applied, and the permeate that has penetrated into the defects is adsorbed on the surface to show traces of defects. The disadvantage of penetrant inspection is that it can only detect the surface defects of the open slope, but cannot detect the buried defects of the surface layer.
1. Characteristics and application scope of color penetrant inspection method
Color penetrant inspection method can also be divided into dry imaging method, wet imaging method and developer-free imaging method according to different imaging processes.
Color penetrant inspection method can be used for the inspection of the following parts:
1) Inspection of bevel cut surface or machined surface before welding.
2) Inspection of the weld and the surface of the near seam area.
3) Inspection of the weld bead surface during the welding process.
4) Inspection of the surface of the weld scar after the temporary assembly and positioning of the tie-bar plate is removed.
2. Colored penetrant flaw detector
1) Washable color penetrant: The principle of action is similar to that of the washable fluorescent penetrant, but it does not require an ultraviolet light source, and the inspection cost is lower.
2) Post-emulsion coloring penetrant: The principle of action is similar to that of the post-emulsion fluorescent coloring penetrant, but it does not require an ultraviolet light source, and the inspection cost is lower.
3) Solvent-removing color penetrant: It can be used in sprinkler irrigation, easy to carry, suitable for on-site inspection of large-scale structural welds, and can also be used for on-site weld inspections.