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.
QNDE 2010 Annual Review of Progress in Quantitative Nondestructive Evaluation, July 18-23, 2010, San Diego, California, USA
Series: AIP Conference Proceedings; no. 1335