Measurement of ultrasonic scattering attenuation in austenitic stainless steel welds: realistic input data for NDT numerical modeling.
Multipass welds made of 316L stainless steel are specific welds of the primary circuit of pressurized water reactors in nuclear power plants. Because of their strong heterogeneous and anisotropic nature due to grain growth during solidification, ultrasonic waves may be greatly deviated, split and attenuated. Thus, ultrasonic assessment of the structural integrity of such welds is quite complicated. Numerical codes exist that simulate ultrasonic propagation through such structures, but they require precise and realistic input data, as attenuation coefficients. This paper presents rigorous measurements of attenuation in austenitic weld as a function of grain orientation. In fact attenuation is here mainly caused by grain scattering. Measurements are based on the decomposition of experimental beams into plane-wave angular spectra and on the modeling of the ultrasonic propagation through the material. For this, the transmission coefficients are calculated for any incident plane wave on an anisotropic plate. Two different hypotheses on the welded material are tested: first it is considered as monoclinic, and then as triclinic. Results are analyzed, and validated through comparison to theoretical predictions of related literature. They underline the great importance of well-describing the anisotropic structure of austenitic welds for UT modeling issues.
Aix-Marseille Université, CNRS - LMA UPR 7051 site LCND, Avenue Gaston Berger, 13625 Aix-en-Provence, France. Electronic address: marie-aude.ploix@univ-amu.fr.
Marie-Aude
MA
Ploix
LVA, INSA Lyon, 25bis Avenue Jean Capelle, 69621 Villeurbanne Cedex, France.
Philippe
P
Guy
EDF R&D, Département MMC, Site des Renardières, 77818 Moret-sur-Loing, France.
Bertrand
B
Chassignole
Aix-Marseille Université, CNRS - LMA UPR 7051 site LCND, Avenue Gaston Berger, 13625 Aix-en-Provence, France.
Joseph
J
Moysan
Aix-Marseille Université, CNRS - LMA UPR 7051 site LCND, Avenue Gaston Berger, 13625 Aix-en-Provence, France.
Gilles
G
Corneloup
LAUM, Université du Maine, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9, France.
Rachid
R
El Guerjouma
Attenuation measurement; Austenitic weld; Grain scattering; Plane-wave angular spectrum; Triclinic material