Material Sound Velocities
The table below lists typical longitudinal wave ultrasonic velocities in a variety of common materials that can be measured with ultrasonic thickness gages. Note that this is only a general guide. The actual velocity in these materials may vary significantly due to a variety of causes such as specific composition or microstructure, grain or fiber orientation, porosity, and temperature. This is especially true in the case of cast metals, fiberglass, plastics, and composites. For best accuracy in thickness gaging, the sound velocity in a given test material should always be measured by performing a velocity calibration on a sample of known thickness.