DETERMINATION OF CRYSTALLOGRAPHIC TEXTURE IN STEEL PLATES USING LASER-GENERATED SURFACE WAVES.

A laser-ultrasonic approach based on the propagation of surface skimming longitudinal wave (P-wave) and Rayleigh wave (SAW) is investigated for the measurement of crystallographic texture in moderately thick steel plates. The angular dependence of the P-wave and SAW velocities presents different patterns, both of amplitude of a few % attributed to texture. Results obtained from fitting the angular profiles using relevant expressions for P-wave and SAW confirm that texture coefficients may accurately be measured by this approach. Moreover, the difference of the P-wave and SAW profiles is shown to be very robust against small path length changes or other detrimental effects such as surface roughness. For actual measurements on large plates, a solution based on the rotation of a generation line using an axicon lens is tested. Texture variations across the width of steel plates and the influence of residual stress are discussed. [ABSTRACT FROM AUTHOR]