Which inspection technique involves the use of a liquid during the assessment of parts?

Liquid penetrant inspection is the correct technique that involves the use of a liquid during the assessment of parts. This method is specifically designed to reveal surface discontinuities by applying a liquid penetrant to the surface of the material. After a dwell time, excess penetrant is removed, and a developer is applied, drawing the penetrant out of flaws and making them visible for inspection.

This technique is effective for detecting small surface cracks and is widely used in various industries, including aerospace, to ensure the integrity of components. The use of a liquid is vital because it enables the penetrant to enter and highlight defects that might otherwise go unnoticed.

Other methods, such as ultrasonic and magnetic particle inspections, employ different principles and techniques. For example, ultrasonic inspection uses high-frequency sound waves to detect imperfections, while magnetic particle inspection employs magnetic fields to identify flaws. Visual inspection relies on direct observation without any additional liquids or penetrants. Liquid penetrant inspection specifically stands out due to its reliance on liquid media to find surface defects.