Remote-field eddy current signal representation

Journal Article · Thu Jul 01 00:00:00 EDT 1993 · Materials Evaluation; (United States)

OSTI ID:6463131

Atherton, D L; Mackintosh, D D; Sullivan, S P; Dubois, J M.S.; Schmidt, T R ^[1]

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1. Queen's Univ., Kingston, Ontario (Canada). Dept. of Physics.

While conventional reflected impedance eddy current testing (ET) techniques are limited by skin depth considerations to near surface defects, the RFEC (remote field eddy current) technique exploits skin effects. The RFEC method is a through-wall inspection technique. Only the field which has made a double transit of the pipe wall is detected. The skin depth equation can be used to predict the approximate effect of metal loss on the RFEC signal. Metal loss effectively reduces the shielding so that the attenuation and phase lag of the field is less. A method of analyzing RFEC defect signals is therefore to compare the signals with the phase and amplitude in uncorroded pipe. RFEC probes are used for inspecting ferromagnetic and nonferromagnetic tubulars for corrosion and, since eddy current detectors are generally well suited to crack detection, there is considerable interest in their potential to detect stress corrosion cracking in pipelines. Here the authors first of all summarize the impedance plane representation and scope monitor displays customarily used for conventional exploring coil ET probes in tubes. They then present the normalized voltage plane and monitor displays that are most appropriate for RFEC probes. They discuss the similarities and differences between the preferred monitor displays.

• OSTI ID: 6463131
• Journal Information: Materials Evaluation; (United States), Journal Name: Materials Evaluation; (United States) Vol. 51:7; ISSN MAEVAD; ISSN 0025-5327
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420500* -- Engineering-- Materials Testing
AMPLITUDES
CHEMICAL REACTIONS
COMPUTER OUTPUT DEVICES
COMPUTER-GRAPHICS DEVICES
CORROSION
CRACKS
DATA ANALYSIS
DEFECTS
DIAGRAMS
DISPLAY DEVICES
EDDY CURRENT TESTING
ELECTROMAGNETIC TESTING
IMPEDANCE
INSPECTION
MATERIALS TESTING
MEASURING INSTRUMENTS
NONDESTRUCTIVE TESTING
PIPELINES
SIGNALS
STRESS CORROSION
TESTING