Which non-destructive testing method is commonly used to detect surface-breaking defects by applying a liquid penetrant?

Which non-destructive testing method is commonly used to detect surface-breaking defects by applying a liquid penetrant?

• A. Visual inspection
• B. Liquid penetrant testing
• C. Magnetic particle testing
• D. Radiographic testing

Answer: (B)

Liquid penetrant testing is a non-destructive method that targets flaws open to the surface. The idea is simple: you apply a penetrant liquid to the cleaned surface, and it seeps into any surface-breaking cracks or porosities. After a dwell time, you remove the excess penetrant and apply a developer. The developer draws the penetrant out of the defect and creates a visible or fluorescent indication that shows where the flaw is. This method is ideal for surface-breaking defects because it relies on capillary action at or very near the surface and doesn’t involve radiation or magnetization. It’s fast, cost-effective, and versatile for many materials, but it won’t reveal flaws that don’t reach the surface, and it requires clean, properly prepared surfaces for reliable results.

Liquid penetrant testing is a non-destructive method that targets flaws open to the surface. The idea is simple: you apply a penetrant liquid to the cleaned surface, and it seeps into any surface-breaking cracks or porosities. After a dwell time, you remove the excess penetrant and apply a developer. The developer draws the penetrant out of the defect and creates a visible or fluorescent indication that shows where the flaw is. This method is ideal for surface-breaking defects because it relies on capillary action at or very near the surface and doesn’t involve radiation or magnetization. It’s fast, cost-effective, and versatile for many materials, but it won’t reveal flaws that don’t reach the surface, and it requires clean, properly prepared surfaces for reliable results.