METHOD OF DETECTION AND CHECKING OF DEVELOPMENT OF DEFECTS ON METAL SURFACES OF OBJECTS Russian patent published in 1998 - IPC

FIELD: measurement technology. SUBSTANCE: method refers to checking the condition of surface of loaded metal constructions and objects positioned in corrosion media. Retarded magnetic wave is excited and spread in former of variable electromagnetic field. Surface of object being checked provided with protective coating is positioned in the above-indicated field. Variations of imaginary part of retarded wave propagation constant are converted to informative signal by which presence and size of defects are judged. To remove influence of properties of protective coating material in clearance on measurement results, energy of magnetic field formed by retarded wave is shifted to clearance area. In order to ensure required measurement sensitivity, clearance value is selected to be not in excess of λ_r/2π,, where λ_r- is length of retarded wave passing through former. Configuration of the latter should follow that of checked object surface. EFFECT: more efficient detection and checking. 4 cl