What does the term “A-scan” represent in ultrasonic testing?

The term “A-scan” in ultrasonic testing refers to a one-dimensional display representing the amplitude of the echo signals as a function of time. This technique involves transmitting ultrasonic waves into a material and measuring the echoes that return from internal features, such as flaws or boundaries. The resulting graph displays the amplitude of these echoes on the vertical axis against the time it takes for the echoes to return on the horizontal axis. Each peak in the A-scan represents a reflection from an internal feature, giving technicians valuable information about the presence and location of defects within the material.

This distinction is crucial because it provides a foundational understanding of how ultrasonic testing works and how A-scans are utilized to interpret the integrity of materials. Unlike visual methods that might represent material contours or two-dimensional mappings, the A-scan focuses solely on the temporal characteristics of the reflected sound waves, making it an essential tool for evaluating material conditions.