penetrant method of nondestructive testing

penetrant method of nondestructive testing

An essentially noninstrumental method of nondestructive testing that is not dependent on radiation. A special penetrant substance is applied freely on the test object and allowed to work into tight cracks. The penetrant is removed from all surface areas, and the piece is sprayed with a developer. The developer dries to an even white coating, while the penetrant bleeds up from any flaws through the developer, forming bright-red or fluorescent indications on the white surface. The size of the defect is indicated by the richness of the color, the speed of the bleed-out, and the observed dimensions. Also called dye penetrant testing
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