Evaluation of Acoustic Anisotropy to Image Defects in Weld Metal by Ultrasonic Phased Array

An ultrasonic phased array (PA) does not work well in some weld metals owing to the strong acoustic anisotropy. However, the analysis of anisotropy for the compensation of the shift of the defect image in the PA has not been performed. In this study, we compared the results of imaging a slit in a Ni-based weld metal, commercially available as Inconel alloy 600, in an experiment and in simulations using the analytical solution of group velocity or the finite-difference time-domain (FDTD) method. As a result, we succeeded in reproducing the shift and broadening of the defect image obtained in an experiment by the simulations.