ABSTRACT
Ultrasonic methods have been applied to nondestructive testing (NDT) and material characterization in numerous ways and are among the most important of the techniques used for inspecting metal products. Ultrasonic inspection is safe, versatile, and economical. Effective use of ultrasonic NDT requires skilled operators. It also requires an understanding of the theory of wave propagation and of the characteristics of available equipment on the part of the person responsible for prescribing the testing procedure. Measuring the propagation characteristics of ultrasonic energy is a means of determining internal structures. The ultrasonic techniques have been used successfully in assessing the structure of heat-treated steel castings, the form and amount of graphite in iron castings, the tensile strength of materials, the hardening depth or quality of chilled iron rolls, and the grain size and orientation in uranium, brass, and other alloys. E. D. Nemkina et al. evaluated the use of ultrasonic attenuation in determining the grain orientation of transformer steel.
