Salauze, Ophelie; EDF Centre d'Expertise et d'Inspection dans les Domaines de la Realisation et de l'Exploitation; France
Salauze, O.; EDF Direction Industrielle; France
Session: Meta Modeling
Time: 16:00 - 16:20
Complex materials like multi-pass welds in austenitic stainless steels greatly disturb the propagation of ultrasonic waves and make ultrasonic non-destructive testing difficult. Such welds show anisotropic and heterogeneous structures, with elongated grains, inducing deviation and/or division of the ultrasonic beam associated with a strong attenuation of wave amplitude.
The ATHENA 2D finite elements simulation code has been developed to simulate ultrasonic propagation in the weld, and to properly reproduce these beam distortion phenomena.
The feasibility study presented in this paper aims at developing and testing a new approach with ATHENA, based on simulation, to evaluate the performance of an ultrasonic inspection in terms of zone coverage and sensitivity. The weld, made by manual shield metal arc welding (SMAW), was modeled, using information extracted from welding reports, with the MINA model which predicts columnar grains orientation. Then, the ultrasonic beam was simulated at each scanning position of the probe. The amplitude of the transmitted sound field was computed and compared to the field in the isotropic parent material. The overlay of these beams allowed us to determine the areas of the weld which are not sounded below a given threshold, and to identify areas where the response of a defect is assumed to be weaker. Data compilation obtained with the analysis of the beams calculated in the two scanning directions and with different probes provide additional technical justifications for the evaluation of the performance of ultrasonic testing in austenitic steel welds.