Which non-destructive testing method is specifically used to reveal surface-breaking defects with a penetrant liquid?

Which non-destructive testing method is specifically used to reveal surface-breaking defects with a penetrant liquid?

• A. Dye penetrant
• B. Visual inspection
• C. Eddy current
• D. Ultrasonic testing

Answer: (A)

Dye penetrant testing uses a penetrant liquid to reveal cracks that are open to the surface. The liquid seeps into surface-breaking defects by capillary action, then the excess is removed and a developer is applied. The developer draws penetrant out of the defect and to the surface, creating a visible colored indication (or a fluorescent glow under UV light) that shows where flaws exist. This method is specifically geared toward detecting flaws that break the surface, not subsurface or internal defects. The other methods work differently: visual inspection relies on what you can see on the surface without liquids; eddy current detects flaws via electromagnetic response in conductive materials; ultrasonic testing uses high-frequency sound to identify internal and near-surface defects. None of these use a penetrant liquid to reveal surface-breaking flaws.

Dye penetrant testing uses a penetrant liquid to reveal cracks that are open to the surface. The liquid seeps into surface-breaking defects by capillary action, then the excess is removed and a developer is applied. The developer draws penetrant out of the defect and to the surface, creating a visible colored indication (or a fluorescent glow under UV light) that shows where flaws exist. This method is specifically geared toward detecting flaws that break the surface, not subsurface or internal defects.

The other methods work differently: visual inspection relies on what you can see on the surface without liquids; eddy current detects flaws via electromagnetic response in conductive materials; ultrasonic testing uses high-frequency sound to identify internal and near-surface defects. None of these use a penetrant liquid to reveal surface-breaking flaws.