Which statement is false about penetrant testing?

Which statement is false about penetrant testing?

• A. It is not necessary to remove a film of oil from a part prior to penetrant testing because the penetrant is basically an oil
• B. A film of oil on the surface must be removed prior to testing
• C. Oil on the surface does not affect indications
• D. Cleaning with appropriate solvent is recommended

Answer: (A)

Penetrant testing relies on a clean, oil-free surface so the penetrant can flow into surface flaws by capillary action and produce clear indications after the developer is applied. An oil film on the surface actually interferes with the penetration process and can mask or distort indications, which is why removing any oil before testing is essential. The statement that you don’t need to remove a film of oil is therefore not correct. In practice, you must remove oil from the surface prior to testing, using an appropriate cleaner or solvent and then rinse and dry. Cleaning with a suitable solvent is recommended to ensure the surface is free of contaminants, and oil on the surface does affect indications, so that point is also important to understand.

Penetrant testing relies on a clean, oil-free surface so the penetrant can flow into surface flaws by capillary action and produce clear indications after the developer is applied. An oil film on the surface actually interferes with the penetration process and can mask or distort indications, which is why removing any oil before testing is essential. The statement that you don’t need to remove a film of oil is therefore not correct. In practice, you must remove oil from the surface prior to testing, using an appropriate cleaner or solvent and then rinse and dry. Cleaning with a suitable solvent is recommended to ensure the surface is free of contaminants, and oil on the surface does affect indications, so that point is also important to understand.