Nondestructive Analysis of Textures in Rolled Sheets by Ultrasonic Techniques

Abstract

The preferred grain orientation in polycrystals causes a direction dependence of the ultrasonic wave velocities. In an extensive study, the texture influence on different ultrasonic wave velocities is measured in series of cold-rolled ferritic steel sheets. Based on that, ultrasonic techniques are developed to characterize the texture in terms of the three fourth-order expansion coefficients of the orientation distribution function (ODF). Evaluation equations are given for the application of free ultrasonic longitudinal and shear waves as well as for the application of ultrasonic SH-waves.Furthermore, linear correlations are found between the Δr- and rm-values, characterizing the deep drawability of the sheets and the expansion coefficients C413 and C411, evaluated by ultrasonic techniques. The study demonstrates that ultrasonic techniques hold high promise to evaluate the fourth-order expansion coefficients of the ODF and to characterize the deep drawing behavior of rolled sheets by the use of calibration experiments.