What information does a C-scan typically display in an ultrasonic test?

A C-scan in ultrasonic testing is a method that provides a two-dimensional, plan view representation of the test specimen, effectively illustrating the location and size of discontinuities within the material. This visual representation is obtained by scanning the surface with an ultrasonic transducer that collects data points across the area of interest. Each data point corresponds to the reflected ultrasonic wave, which identifies flaws or discontinuities.

What makes the C-scan particularly valuable is its ability to give a comprehensive overview of the internal structure of the material, allowing inspectors to quickly assess the nature and extent of any detected issues. The image format provides an intuitive understanding of where discontinuities are located, as well as their relative dimensions, which is crucial for evaluating the integrity of the material being tested.

In contrast, the other options relate to different parameters not directly represented by a C-scan. Material density and thickness, wave velocity distribution, and surface roughness profiles may be evaluated by other methods or different types of scans in ultrasonic testing but are not directly depicted in a typical C-scan output.