| 摘要 |
FIELD: nondestructive inspection. ^ SUBSTANCE: method and device can be used for conducting nondestructive inspection of surface layers of current-conducting materials (CCM) during production and exploitation. Surface electric resistance Rn is used as flaw detection parameter, which resistance is measured at constant base l. Value of resistance is used to judge on availability of defects. Method allows eliminating influence of oxide and other coatings having high resistance as well as subsurface defect-free layers with lower electric resistance onto measured value. Coating with high resistance is punched by means of special prods till getting contact with CCM being subjected to inspection. Contact is judged from acute drop in resistance registered by ac ohmmeter tuned for the highest of its measurement current. Resistance is measured at frequency that provides nondestructive inspection of CCM having specified thickness. Device has two prods provided with removable needles having different edge radius. Prods rest against springs having adjusted compression which provide punching of coatings. For taking measurements at small constant bases l, the prods are disposed inside the same case. The prods have eccentricity to provide subsequent adjustment of constant base. ^ EFFECT: improved truth of revealing defects. ^ 2 cl, 1dwg |
