Nondestructive evaluation of the formability of cold-rolled steel sheets using electromagnetic acoustic transducers (EMATs).

Abstract

An ultrasonic technique for determining the r-value in cold-rolled steel sheets is developed. The theory is reviewed for the interrelation between the velocity anisotropy of guided modes along the sheets and the texture (or preferred orientation), which is defined by the orientation distribution coefficients. The electromagnetic acoustic transducers, fabricated with permanent magnets and meanderline coils, allow the quick and easy measurement of transit time of the lowest symmetric (S0) mode. The in-plane average of transit times shows a close correlation with both the r^- -value and {111} pole intensity obtained through X-ray diffraction experiments.