Acoustical characterization of austenitic stainless steel welds for experimental and modeling NDT

抄録

Multipass welds made in 316-L stainless steel are specific welds of the primary circuit in nuclear power plants. Their complex structure complicates ultrasonic assessment of their structural integrity : they present a heterogeneous anisotropy that modifies wave propagation (deviation and division of the beam, high attenuation, high grain noise…). In order to understand ultrasonic propagation in such media, a finite-element model called Athena was developed (INRIA-EDF). Athena predicts ultrasonic beam and particle's velocity in heterogeneous and anisotropic materials, but attenuation has still to be integrated to the code. Our work aims at providing realistic input data of attenuation compatible with the existing model by studying mechanisms leading to attenuation in anisotropic structures. Experimental measurements are made with two immersion techniques using longitudinal waves. Results are presented and compared with theoretical predictions of the literature.