Which method is NOT recommended for removing grease from a penetrant test specimen?

Removing grease from a penetrant test specimen is critical to ensure accurate testing results. Each method has its advantages and limitations based on the test material and the contaminants involved.

Hot water rinsing is not considered an effective method for removing grease because it may not adequately dissolve or emulsify oil-based contaminants. Although hot water can help in loosening grease, it might not remove it completely, particularly if the grease is stubborn or has bonded well with the surface. Additionally, using hot water risks the potential for water to penetrate areas where it shouldn’t, possibly leading to further contamination or affecting the integrity of the specimen.

On the other hand, solvent wiping is a common practice because specific solvents can dissolve grease effectively, allowing for thorough cleaning. Ultrasonic cleaning employs high-frequency sound waves in a liquid solution to agitate and remove contaminants, making it highly effective for intricate parts. Pressure washing can be suitable as well, especially when combined with appropriate degreasing agents, ensuring that surface contaminants are blasted away without leaving residues.

In summary, while hot water rinsing can assist in some cleaning tasks, it's not recommended for greasing removal from penetrant test specimens due to its limited effectiveness against oils and the risk of incomplete cleaning.