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

Which type of developer would you use to obtain the highest sensitivity test results?

1. Dry

2. Non-aqueous wet

3. Aqueous wet

4. Lipophilic

The correct answer is: Non-aqueous wet

Using a non-aqueous wet developer is essential for achieving the highest sensitivity in liquid penetrant testing. This type of developer works by creating a thin film over the surface of the part being tested, allowing for maximum visibility of penetrant that has been drawn out of surface flaws. The non-aqueous nature means that it can provide a clearer contrast against the penetrant, enhancing the detection of smaller or finer discontinuities. Non-aqueous wet developers also have properties that make them particularly effective in situations where contaminants or residual oils may be present on the part's surface. By using this type of developer, the ability to visualize defects is significantly enhanced, which is crucial in critical applications where safety and integrity are paramount. In contrast, dry developers may not provide the same level of sensitivity, as they tend to produce a less pronounced contrast between the penetrant and the developer. Aqueous wet developers, while useful in many scenarios, typically have a tendency to bind with water, which may dilute the penetrant and reduce the visibility of indications on certain surfaces. Lipophilic developers focus on oil-based penetrants and are effective in specific applications but may not be the best option for overall sensitivity compared to non-aqueous wet developers. This makes