What is the term used to define the duration for which a test part is covered with penetrant?

The term that defines the duration for which a test part is covered with penetrant is referred to as the dwell period. This period is critically important in nondestructive testing, specifically in penetrant testing (also known as liquid penetrant testing). During this time, the penetrant seeps into any surface-breaking defects, allowing for a thorough inspection.

The dwell period must be adequately timed to ensure that the penetrant has enough time to fill any flaws present on the surface. If the dwell period is too short, the penetrant may not adequately penetrate defects, reducing the effectiveness of the testing process.

In nondestructive testing contexts, other terms such as penetration time, exposure time, and inspection duration may have different meanings. Penetration time typically refers to the time it takes for the penetrant to enter a defect after exposure, while exposure time may refer to the duration the penetrant is applied to a surface before removal. Inspection duration usually pertains to the total time allotted for inspecting the test part after applying the penetrant, which could include time spent on interpreting the results.