Liquid Penetrant Testing
Penetrant testing is a non-destructive method for detecting surface-breaking defects. A colored or fluorescent liquid is applied to cracks, which are then made visible by capillary action.
Physical-Chemical Mechanism of Action
A colored or fluorescent liquid is applied to the surface to be tested. This liquid penetrates cracks and fissures by capillary action, a physical property where liquids are drawn into narrow gaps or cracks.
Metallurgical Relevance & Welding Risks
Penetrant testing is especially important for checking weld quality and integrity. Missing or too-small cracks can be hard to detect, but they can lead to later failures. The test also reveals surface defects like corrosion or contamination.
Workshop Practice & Instructions
1. Prepare the surface to be tested clean and dry.
2. Spray the colored or fluorescent liquid into the cracks.
3. Let the liquid sit for a few minutes to fully penetrate.
4. Clean the surface with a developer, if necessary, to make the defect visible.
5. Document all found defects and note the test results.