Evaluating the grain size in curved components using the ultrasonic attenuation method with diffraction correction

Ultrasonic wave propagation in curved components was simulated based on the Multi-Gaussian beam theory to eliminate the negative influence of the surface curvature and water path on grain size attenuation evaluation. The multi-frequency weighted attenuation evaluation model with diffraction correction was introduced into the measured attenuation spectrum to control the systematic error. The experimental results show that for 6 blocks with different curvatures and the same mean grain size, the relative error was reduced from 15.41% to 4.28% by using the presented method, and the standard deviation of the error was 15.92% of that of the traditional method.