Liquid Penetrant Testing Level 1 (PT-1) Practice Exam

Which surface condition could negatively impact a liquid penetrant test?

1. Dry surface

2. A rough weld

3. Clean surface

4. Polished surface

The correct answer is: A rough weld

The surface condition that could negatively impact a liquid penetrant test is a rough weld. A rough weld can create a challenging environment for penetrant to adequately permeate into any surface-breaking defects. The grooves and uneven surfaces may disrupt the capillary action needed for the penetrant to be drawn into cracks or voids, resulting in insufficient indication or missed defects during the inspection process. In contrast, a dry surface is beneficial as it helps ensure that the penetrant spreads uniformly without dilution or contamination. A clean surface is essential because any contaminants can interfere with the adhesion or penetration of the liquid into the defects. A polished surface, while smooth, can still be suitable for testing if it is free of contaminants; however, if overly smooth, it may require careful consideration to ensure good penetrant retention. In essence, while surface conditions such as dryness and cleanliness are beneficial, a rough weld specifically hinders the effectiveness of liquid penetrant testing by affecting the penetrant's ability to detect flaws properly.