How does a penetrant test typically begin on a specimen?

A penetrant test begins with pre-cleaning the surface of the specimen to ensure the accuracy and effectiveness of the inspection. This step is crucial because any contaminants such as dirt, grease, oil, paint, or rust can interfere with the ability of the penetrant to enter defects or discontinuities on the surface of the material. Proper cleaning prepares the surface for the penetrant application, allowing for better penetration into any flaws and ensuring that the test results are reliable.

Removing any surface contamination lays the foundation for the subsequent steps, which include applying the penetrant and then the developer to reveal any defects. This sequence is essential for achieving clear and interpretable testing outcomes, as any residue left from pre-cleaning can mask potential indications of defects.