Ultrasonic Testing of Materials

Abstract

A pulse-echo method using shouldered samples has been used for the first time to determine the ultrasonic attenuation at room and elevated temperatures. The theory of the method has been worked out and the method is applied to carbon and stainless steels at 5 MHz in the temperature range 20°-800°C. It is observed that the attenuation due to grain scattering of ultrasonic waves according to Bhatia's theory together with Papadakis's refinements is not sufficient to explain the entire temperature dependence of attenuation. A maximum in the attenuation is observed in carbon steels at 200°C, which is the Curie temperature of the ferromagnetic cementite structure. In nonmagnetic stainless steel (18/8) the acoustic attenuation in the sample heated at 800°C for 1 h remains practically constant with respect to temperature. © 1968 The American Institute of Physics.