In angle beam testing of plate, laminations parallel to the front surface are often missed.

In angle beam testing of plate, laminations parallel to the front surface are often missed.

• A. Perpendicular to the sound wave
• B. Laminations parallel to the front surface
• C. Random orientation
• D. Not present

Answer: (B)

In angle beam testing, the transducer sends an oblique wave into the plate and looks for reflections from planar discontinuities. A lamination that lies parallel to the front surface presents a defect plane almost parallel to the surface, so the incident energy does not meet that plane at an angle that produces a strong back reflection. The wave tends to skim along or transmit across the laminate rather than reflect toward the transducer, resulting in a weak or missing echo. Because backscatter strength depends on the orientation of the defect relative to the beam, laminations parallel to the front surface are particularly hard to detect with angled beams, whereas defects with planes more perpendicular to the beam generate stronger reflections. This is why those laminations are often missed in angle-beam plate inspections.

In angle beam testing, the transducer sends an oblique wave into the plate and looks for reflections from planar discontinuities. A lamination that lies parallel to the front surface presents a defect plane almost parallel to the surface, so the incident energy does not meet that plane at an angle that produces a strong back reflection. The wave tends to skim along or transmit across the laminate rather than reflect toward the transducer, resulting in a weak or missing echo. Because backscatter strength depends on the orientation of the defect relative to the beam, laminations parallel to the front surface are particularly hard to detect with angled beams, whereas defects with planes more perpendicular to the beam generate stronger reflections. This is why those laminations are often missed in angle-beam plate inspections.