The term used to define the period of time in which the test part is covered with penetrant is

The term used to define the period of time in which the test part is covered with penetrant is

• A. Penetration time (dwell time)
• B. Drying time
• C. Exposure time
• D. Curing time

Answer: (A)

Dwell time, also called penetration time, is the period during which the penetrant is left on the part to enter surface-breaking defects. This interval relies on capillary action to fill cracks and porosities, so the penetrant has enough time to get into defects but not so long that it bleeds and creates excess surface film. If the dwell time is too short, defects may not be penetrated; if too long, surface bleeding can obscure indications and reduce readability. After dwell, excess penetrant is removed, the part is dried, and a developer is applied to bring the penetrant out of defects for inspection.

Dwell time, also called penetration time, is the period during which the penetrant is left on the part to enter surface-breaking defects. This interval relies on capillary action to fill cracks and porosities, so the penetrant has enough time to get into defects but not so long that it bleeds and creates excess surface film. If the dwell time is too short, defects may not be penetrated; if too long, surface bleeding can obscure indications and reduce readability. After dwell, excess penetrant is removed, the part is dried, and a developer is applied to bring the penetrant out of defects for inspection.