What is the recommended condition of materials before conducting LPT?

The recommended condition of materials before conducting Liquid Penetrant Testing (LPT) is that the surface must be clean and free of contaminants. For LPT to be effective, the surface must allow the penetrant to access any discontinuities without interference from substances that can obstruct its penetration. Contaminants such as oils, grease, dirt, rust, or paint can fill cracks or voids and impair detection of flaws because they create a barrier between the penetrant and the material.

A clean surface ensures that the penetrant can seep into any surface-breaking discontinuities, allowing for accurate evaluation of the material. Proper surface preparation is critical for optimal results, ensuring that the penetrant adequately adheres to and enters any defects present in the material being tested.