Title: Remote field eddy current tube inspection using giant magneto-resistance sensors

Authors: Dário Jerónimo Pasadas; A. Lopes Ribeiro; Tiago Jorge Rocha; Helena Maria Geirinhas Ramos

Addresses: Instituto de Telecomunicações, IST, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal ' Instituto de Telecomunicações, IST, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal ' Instituto de Telecomunicações, IST, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal ' Instituto de Telecomunicações, IST, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal

Abstract: This paper presents a probe that permits the detection of longitudinal and circumferential defects in stainless steel tubes. The defect detection is made by a measurement system based on eddy current (EC) and remote field testing (RFT). The probe includes an excitation coil and a giant magneto-resistance (GMR) magnetic sensor. This GMR sensor has high sensitivity in a large frequency range (0 Hz-1 MHz) which makes it a good candidate to analyse several defects in tubes using a remote field testing method. Experimental data were acquired by a measurement system to verify the sensitivity of the GMR in defect detection and to create a new probe. A simulation was made in order to verify the veracity of the obtained experimental results when the remote field testing method is applied. Finally, 2D maps representing the GMR output response at several angles of rotation around the defects were made and compared in this paper.

Keywords: nondestructive testing; NDT; remote field testing; RFT; giant magneto-resistance; GMR sensors; eddy current; tube inspection; stainless steel tubes; tube defects; simulation.

DOI: 10.1504/IJIED.2014.064093

International Journal of Industrial Electronics and Drives, 2014 Vol.1 No.3, pp.167 - 173

Received: 19 Oct 2013
Accepted: 19 Jan 2014
Published online: 30 Aug 2014 *

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