Excess penetrant (all penetrant except that which is in discontinuities) is removed from the specimen

Excess penetrant (all penetrant except that which is in discontinuities) is removed from the specimen

• A. Before dwell time
• B. During dwell time
• C. Never
• D. After the required penetrant dwell time has elapsed

Answer: (D)

In liquid penetrant inspection, the penetrant is allowed to dwell so that it can enter surface-breaking flaws by capillary action. After the required dwell time has elapsed, you remove the excess penetrant from the surface, leaving only the penetrant that has entered discontinuities. This step is crucial because the developer will draw out that trapped penetrant to create visible indications. If you remove excess too early, penetration into flaws may be incomplete and you could miss indications. If you never remove the excess, surface film would mask or obscure the indications, reducing contrast and detection capability.

In liquid penetrant inspection, the penetrant is allowed to dwell so that it can enter surface-breaking flaws by capillary action. After the required dwell time has elapsed, you remove the excess penetrant from the surface, leaving only the penetrant that has entered discontinuities. This step is crucial because the developer will draw out that trapped penetrant to create visible indications. If you remove excess too early, penetration into flaws may be incomplete and you could miss indications. If you never remove the excess, surface film would mask or obscure the indications, reducing contrast and detection capability.