Development of SQUID-based non-destructive evaluation system for detecting fatigue induced transformation of δ-ferrite to non-magnetic phases

• Published in: NDT & E international : independent nondestructive testing and evaluation Vol. 40; no. 3; pp. 215 - 219
• Main Authors: Nagendran, R., Janawadkar, M.P., Pattabiraman, M., Baisnab, D.K., Baskaran, R., Vaidhyanathan, L.S., Hariharan, Y., Raj, Baldev, Nagesha, A., Valsan, M., Bhanu Sankara Rao, K.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.04.2007; Elsevier Science
• Subjects: Austenitic stainless steels; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fatigue; Fundamental areas of phenomenology (including applications); Materials science; Materials testing; Measurement and testing methods; Non-destructive testing; Physics; Solid mechanics; SQUIDs; Structural and continuum mechanics; 85.25.Dq; Austenitic stainless steels; Fatigue; 81.40.Np; Non-destructive testing; 81.70.Ex; SQUIDs; Data acquisition; Output signal; SQU#Ds; Non-destructive testing; Fatigue; Austenitic stainless steels; Ferrites; Ferrite; Fatigue test; Welded joint; Content; Superconducting quantum interferometer device; Cryostat; Liquid helium; Metrology; 85.25.Dq; 81.70.Ex; 81.40.Np; Fillet weld; Non destructive test; High temperature superconductor
• ISSN: 0963-8695; 1879-1174
• DOI: 10.1016/j.ndteint.2006.10.009

A SQUID based NDE set up based on a precision XY scanner developed and used to evaluate the transformation of δ-ferrite to non-magnetic phases during fatigue in weldment samples has been described. The SQUID based NDE system comprises of a SQUID insert housed in a liquid helium cryostat, precision XY scanner for the sample movement and the data acquisition module to acquire the SQUID output signal with respect to the sample coordinates for flat plate as well as cylindrical samples. The system has been used to detect δ-ferrite content of virgin and fatigue tested austenitic stainless steel weldments.