METHOD FOR DETECTING FLAW BY PENETRATION OF QUICK-DRYING LIQUID

PROBLEM TO BE SOLVED: To detect even a surface flaw of an interior part hard to access or a narrow part, by letting a quick-drying penetration liquid penetrate a surface of a body to be tested, drying the liquid and monitoring an adhesion state of the penetration liquid of the surface. SOLUTION: A fiberscope 3 while monitored at a monitor 4 is inserted to a through hole 10 of a body 9 to be tested and stopped at a hole of a flaw detection part. A volatile penetration liquid (alcohol, acetone or the like) as a quick-drying penetration liquid is applied from the hole of the flaw detection part to the periphery of the hole by a penetration liquid application device 1. Thereafter, while the monitor 4 is observed, air, fluorine, nitrogen or the like is sent by a dryer 2 to dry the penetration liquid. An adhesion state of the penetration liquid at a surface is observed. If a defect is present, the penetration liquid exudes in the periphery of the defect. A size of the exudation is measured by eyes or by image-processing, etc., so that the presence/absence and a size of the defect can be specified. Since a work for removing an excessive penetration liquid or applying a developer is not necessary, workability is improved.