Nickel-based austenitic weldments are widely used in steam generator, however it’s difficult for inspection because of its inhomogeneous and anisotropic elastic behaviors. The anisotropic and heterogeneous characteristics of austenitic welds together with a coarse-grained structure (elongated and oriented grains) lead to the following phenomena: scattering, attenuation, skewing, splitting, and divergence of the ultrasonic beam. To improve the ultrasonic inspection, beam behavior in weld need to be understood theoretically and experimentally. For that purpose, water immersed C-scans have been performed with respect to different parts (base material, austenite weld) of the weldments using one 5MHz transducer as transmitter at one side of the specimen and one 5MHz pinducer on the other side as receiver. Beam skewing and splitting is observed, 2D FFT are performed to obtain scan image in frequency domain and echodynamic curve is extracted from the C-scan data. The experiments results are also compared with the simulation results using multi-Gaussian beam model.

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