In nondestructive testing, which method is primarily used to locate surface-breaking defects by applying a liquid penetrant?

In nondestructive testing, which method is primarily used to locate surface-breaking defects by applying a liquid penetrant?

• A. Radiographic
• B. Ultrasonic
• C. Magnetic Particle
• D. Liquid Penetrant

Answer: (D)

Liquid penetrant testing focuses on surface-breaking flaws. A penetrant liquid is applied to the cleaned surface and seeps into any cracks or voids that are open to the surface by capillary action. After a dwell time, the excess penetrant is removed, and a developer is applied. The developer draws the penetrant out of the flaw, creating a visible or fluorescent indication that reveals the defect under the appropriate lighting (visible dye with white light or fluorescent dye with UV light). This method is quick, simple, and cost-effective for locating surface flaws in non-porous materials, though it only detects defects that reach the surface and is limited for certain materials or coatings.

Liquid penetrant testing focuses on surface-breaking flaws. A penetrant liquid is applied to the cleaned surface and seeps into any cracks or voids that are open to the surface by capillary action. After a dwell time, the excess penetrant is removed, and a developer is applied. The developer draws the penetrant out of the flaw, creating a visible or fluorescent indication that reveals the defect under the appropriate lighting (visible dye with white light or fluorescent dye with UV light). This method is quick, simple, and cost-effective for locating surface flaws in non-porous materials, though it only detects defects that reach the surface and is limited for certain materials or coatings.