What information can be derived from a B-scan in ultrasonic testing?

• A. A three-dimensional image of the specimen
• B. A detailed surface profile of the material
• C. A two-dimensional cross-sectional view revealing internal structures and flaws
• D. A graphical representation of external dimensions only

Answer: (C)

In ultrasonic testing, a B-scan provides a two-dimensional cross-sectional view of the internal structures of a specimen. This visualization is essential because it allows inspectors to assess the presence of flaws, such as cracks or voids, within the material. Unlike other scanning techniques that may focus on surface details or external dimensions, the B-scan specifically highlights the internal features by displaying amplitude information from ultrasonic signals as they interact with the materials being tested. This capability makes it invaluable for detecting and characterizing subsurface discontinuities, thus providing a deeper insight into the integrity of the material without causing any damage.