Reflection indications from a weld area using the angle beam technique may represent which of the following?

• A. Porosity
• B. Cracks
• C. All of the above
• D. Weld bead

Answer: (C)

In angle beam ultrasonic testing, a reflection appears whenever the wave meets a change in material properties or a boundary. Porosity inside the weld area consists of small gas pockets that act as many tiny reflectors, so the ultrasound bounces back and shows indications in the weld. Cracks present as planar discontinuities that reflect energy strongly, producing clear echoes at the inspection angle. The weld bead itself is a geometric and impedance change compared to the surrounding metal, so the weld bead region can reflect the wave even if there isn’t a flaw, due to shape, roughness, or boundary effects. Because any of these features can cause a reflection in the weld area, “All of the above” is the best choice. In practice, you’d interpret echoes by looking at their pattern, size, and orientation to tell whether they represent a defect, geometry, or a benign reflection.