DocumentCode :
1066831
Title :
Eddy-Current-Based SQUID-NDE for Detection of Surface Flaws on Copper Tubes
Author :
Hatsukade, Yoshimi ; Okuno, Shinya ; Mori, Kazuaki ; Tanaka, Saburo
Author_Institution :
Toyohashi Univ. of Technol., Aichi
Volume :
17
Issue :
2
fYear :
2007
fDate :
6/1/2007 12:00:00 AM
Firstpage :
780
Lastpage :
783
Abstract :
An eddy-current-based SQUID-NDE system has been developed to detect shallow surface flaws of less than 50 mum in depth on heat-exchanger copper tubes using an HTS-SQUID gradiometer and an Helmholtz-coil-type inducer. In this study, detectable flaw sizes on the tubes were investigated by experiments and simulation. Copper tube specimens with flaws of various sizes were inspected by the system with an excitation field of 5.6 muT at 3 kHz. A magnetic anomaly due to the shallowest flaw of 10 mum depth, 100 mum width and 15 mm length was successfully detected. The experimental results showed that the magnetic signal amplitude due to a flaw was proportional to the effective flaw size given by the product of flaw depth, width and length. A numerical simulation was carried out to calculate the magnetic signal from a flaw on a copper tube to determine the dependence on the flaw size. It is concluded that a flaw with a volume of 106 mum3 should be detectable by improving the system parameters.
Keywords :
copper; eddy current testing; flaw detection; pipes; HTS-SQUID gradiometry; Helmholtz-coil-type inducer; detectable flaw sizes; eddy-current-based SQUID-NDE system; heat-exchanger copper tubes; shallow surface flaws detection; Coils; Copper; Eddy current testing; Eddy currents; Fabrication; Inorganic materials; Metals industry; Numerical simulation; Petroleum; Surface discharges; Copper tube; NDE; eddy current; flaw size HTS-SQUID; surface flaw;
fLanguage :
English
Journal_Title :
Applied Superconductivity, IEEE Transactions on
Publisher :
ieee
ISSN :
1051-8223
Type :
jour
DOI :
10.1109/TASC.2007.898131
Filename :
4277438
Link To Document :
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