What should the cleanliness of the test surface ensure during PT?

The cleanliness of the test surface is crucial in Liquid Penetrant Testing because it ensures visibility for indications. A clean surface allows for better penetration of the liquid penetrant into any discontinuities or defects present. Surface contaminants such as dirt, grease, oil, or oxidation can obscure the indications created when the penetrant is drawn out of these defects during the developer application. If the surface is not appropriately cleaned, the presence of these contaminants can hinder the ability to correctly identify and assess flaws in the material, leading to false negatives or missed indications. Therefore, maintaining a clean test surface is fundamental to the effectiveness and reliability of the liquid penetrant testing process.