Ultrasonic wheel units may be used for which examination types?

• A. Straight or longitudinal examinations
• B. All of the above
• C. Angle beam or shear wave examinations
• D. Surface wave or Rayleigh wave examinations

Answer: (B)

Ultrasonic wheel units are versatile probes designed to scan curved surfaces and deliver ultrasound in different modes by changing how the beam is launched and coupled. For straight or longitudinal examinations, the wheel can be set so the beam enters the material normally, allowing direct, through-thickness inspection of internal features. For angle beam or shear wave examinations, the wheel’s geometry or an attached wedge redirects the beam to enter at an oblique angle, producing shear waves that are useful for detecting flaws oriented in specific directions, such as those in welds. For surface wave or Rayleigh wave examinations, the setup can excite waves that travel along the surface, which are particularly sensitive to near-surface defects.

Because a wheel unit can be configured to support these multiple wave modes, all of the listed examination types are achievable with this type of probe.