Abstract:

：Due o the difficulty of the accurate description of the grain structure and orientation, discrepancy occurs between the ultrasonic inspection simulation and experimental results for anisotropic coarse-grained materials. A modeling method based onelectron backscattered diffraction (EBSD) technique is proposed to quantitative describe the grain structure and orientation. A 96 mm×12 mm crystal orientation map for the radial-axial cross section of a centrifugally cast austenitic stainless steel (CCASS) specimen is acquired using the EBSD technique. A 15° misorientation angle is selected for the grain “orientation unification”. The bond transformation is used to determine the stiffness matrix of the grains with different orientations in the model, thus realizing quantitative description of the complex elastic characteristics. A CCASS ultrasonic inspection model is built and numerically calculated by finite difference time domain method. The simulation results of CCASS ultrasonic testing reproduced typical structural noise and decrease of central frequency quite well. The modeling method provides effective solution to reveal the mechanism of ultrasonic scattering in the anisotropic coarse-grained structure.

Key words: anisotropic, coarse-grained, simulation, ultrasonic inspection, electron backscattered diffraction