Non-Destructive Testing (NDT) Practice Test

What is a necessary step after applying the fluorescent penetrant?

1. Drying the surface completely.

2. Washing off excess penetrant.

3. Heating the component.

4. Performing a visual inspection.

The correct answer is: Washing off excess penetrant.

Washing off excess penetrant is an essential step after applying the fluorescent penetrant in the non-destructive testing process. This step is crucial because it ensures that only the penetrant that has entered any surface discontinuities or flaws remains on the surface of the test material. If excess penetrant is not removed, it can obscure the indications of any defects, leading to potential false readings during the inspection process. Proper washing techniques help to enhance the visibility of the defects under ultraviolet light, as the residual penetrant that remains within the cracks or voids will fluoresce brightly, while the excess on the surface will be removed, allowing for a clearer assessment of the material's integrity. Following the removal of excess penetrant, other processes, such as drying the surface and performing a visual inspection, are indeed important, but the immediate necessity after application is to wash off any excess material to ensure accurate evaluation of the component being tested.