Liquid Penetrant Testing Level 2 (PT-2) Practice Exam

Which penetrant process excels in detecting very fine discontinuities?

1. Solvent removable

2. Water washable

3. Post emulsifiable

4. Magnetic particle

The correct answer is: Post emulsifiable

The post-emulsifiable penetrant process is particularly effective in detecting very fine discontinuities due to its unique methodology. In this process, the penetrant is first applied to the surface, allowing it to seep into any surface-breaking flaws. After a specified dwell time, an emulsifier is applied on top of the penetrant. This emulsifier allows for the washing away of excess penetrant while enabling the penetrant that has entered discontinuities to remain in place. One of the key features of this method is its ability to utilize a sensitizing emulsifier, which improves the retention and development of fine defects. This process allows for greater sensitivity and consistency in results, particularly for detecting very fine cracks or porosities that may go unnoticed with other methods. In contrast, while other processes may also detect discontinuities, they may not perform as well on very fine defects. Solvent removable and water washable processes can dilute the penetrant or wash it away too quickly, which may not be optimum for detecting very subtle indications in the material.