Ultrasonic Measurement of Anisotropy in Rolled Materials Using Surface Wave

An ultrasonic technique for measuring the velocity of surface wave is proposed, and is applied to determine the velocity as a function of propagating direction in aluminum 5052, 5083 and 6061, and steel SM41A. From these data, each slowness diagram in the specimens was determined and it was found that this diagram can be approximated to a ellipse. As a measure of an anisotropy in the surface, BR was taken, where BR is a relative difference in the major and minor axes of the sllipse. The values of BR obtained in the specimens were the order of 10-3 to 10-4, and were smaller than Bs, the measure of anisotropy obtained by shear wave.