Discontinuities in wrought products tend to be oriented in which direction?

• A. Randomly
• B. In the direction of grain flow
• C. At right angles to the entry surface
• D. At right angles to the grain flow

Answer: (B)

Discontinuities in wrought products tend to align with the direction of grain flow created during forming. When metal is worked by rolling or forging, grains elongate along the direction of deformation and any defects—such as inclusions, porosity, or seams—tend to become elongated or aligned in that same path. This means they commonly run parallel to the grain flow, not randomly distributed and not perpendicular to it or to the entry surface. Knowing this helps in inspection, because the ultrasound is most sensitive to planar features when the sound beam is oriented along the defect plane, i.e., parallel to the grain flow.