Ultrasonic and structural characterization of anisotropic austenitic stainless steel welds: Towards a higher reliability in ultrasonic non-destructive testing

• Published in: NDT & E international : independent nondestructive testing and evaluation Vol. 43; no. 4; pp. 273 - 282
• Main Authors: Chassignole, B., El Guerjouma, R., Ploix, M.-A., Fouquet, T.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-06-2010; Elsevier
• Subjects: Acoustical measurements and instrumentation; Acoustics; Anisotropy; Attenuation; Austenitic stainless steels; Cross-disciplinary physics: materials science; rheology; Deviation; Engineering Sciences; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Materials science; Materials testing; Mathematical models; Mechanics; Modeling; Non-destructive testing; Nondestructive testing; Nuclear engineering; Physics; Ultrasonic; Ultrasonic testing; Wave propagation; Weld; Welded joints; Anisotropy; Nuclear engineering; Attenuation; Non-destructive testing; Modeling; Ultrasonic; Weld; Austenitic stainless steel; Nuclear industry; Acoustic measurement; Coolant; Anisotropic material; Pipe; Finite element method; Defect characterization; Welded joint; Piping; Sound scattering; Ultrasonic control; Defect size; Coarse grain structure; Metrology; Reliability; Non destructive test; modeling; attenuation
• ISSN: 0963-8695; 1879-1174
• DOI: 10.1016/j.ndteint.2009.12.005

The non-destructive testing of austenitic stainless steel welds of the primary coolant piping system is a significant problem for the nuclear industry. Ultrasonic techniques would be very helpful to detect, locate and size potential defects. Unfortunately, austenitic welds are coarse-grained, heterogeneous and anisotropic. This leads to aberration and scattering of the ultrasonic waves. In this paper, we present several experimental results of ultrasonic testing of two austenitic welds exhibiting high anisotropy. In order to explain the observed display of wave propagation phenomena such as beam deviation, we use finite element modeling. The modeling is associated with a complete characterization of the inspected welds. Two essential characteristics of the welds are determined: the average elastic constants of the weld and the grain orientations. The capability of the model is illustrated in different testing configurations. This work associating structural characterization and modeling shows that a better understanding of the phenomena of ultrasonic propagation should allow the interpretation and reliability of the industrial inspections of heterogeneous anisotropic welds to be improved
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