Contoured surfaces in immersion testing commonly produce which type of false indication?

• A. Broad based indication
• B. Hashy signal
• C. Peaked indication
• D. Narrow based indication

Answer: (A)

When the surface is contoured, the ultrasonic beam encounters varying angles and path lengths across that surface in immersion testing. This causes the reflected energy to arrive over a range of times, spreading the signal rather than returning as one clean, sharp echo. The outcome is a broad, diffuse reflection that shows up as a broad-based indication. It's important to recognize this as a geometry artifact rather than a real defect, since a true flaw typically produces a sharper, more localized response. Other patterns—such as a single sharp peak, a noisy or hashy signal, or a very narrow, tightly confined response—don’t match the way a curved surface scatters energy in immersion testing.