Abstract
The attenuation measurement of ultrasonic waves in normalized 0.75% carbon steel with various grain sizes is carried out in the frequency range from 2 to 25 megacycles per second. The attenuation increases with frequency slowly in the low frequency range, while very rapidly in the high frequency range, becoming the rate of increase steeper for larger grain size. The coefficient of attenuation α will be expressed by α=B_1f+B_2f^4where f is the frequency and B1 and B2 are the coefficients depending upon the grain sizes. The constant B2 is shown to be proportional with grain size of the steel. It seems possible that the said characteristics of the attenuation of waves are explained basing on Raighley’s theory of the scattering of waves in heterogeneous medium.
