Which mounting method is commonly used for curved surfaces or complex geometries?

• A. Contact with wedge
• B. Immersion
• C. Air-coupled transducer
• D. Wedgeless contact

Answer: (B)

Immersion mounting uses a water-filled path between the transducer and the part, so the coupling layer is flexible and conforms to curves and complex shapes. This makes it easy to scan curved surfaces and geometries without fighting with gaps or maintaining a precise contact angle. The liquid provides uniform coupling across the irregular surface, allowing consistent inspection sensitivity as you move over the part.

Other methods rely on solid contact or air coupling. A wedge sets a fixed angle and requires a smooth, flat or regularly contoured surface for reliable contact, which is hard to maintain on curved or intricate geometries. Wedgeless contact still needs good direct contact and uniform coupling, which can be difficult over complex shapes. Air-coupled transducers depend on an air gap, which greatly attenuates and distorts the signal, making it unsuitable for precise flaw detection on curved surfaces.