Geometrically anisotropic probes: an improved eddy current technique

Journal Article · Mon Jun 01 00:00:00 EDT 1987 · J. Nondestr. Eval.; (United States)

DOI:https://doi.org/10.1007/BF00568889· OSTI ID:6287065

Mayos, M; Muller, J L

Geometrically anisotropic eddy current probes are a type of separate function probes especially fit to the detection of defects showing a preferential direction. This kind of flaw induces a coupling between the transmitter and the receiver by guiding eddy currents from the one to the other. On the other hand, this coupling will be almost non-existent in the presence of defects or spurious effects not displaying this geometrical particularity. Basic studies on an elementary two-coil set-up allow the acknowledgment of the intrinsic qualities of such probes: good signal-to-noise ratio, influence field practically constant on the whole defect length, ability to detect bridged defects, insensitivity to lift off. These results can be improved by achieving multicoils probes adapted to different kinds of problems. An application to continuous casting slabs testing yields very interesting results in the detection of cracks, while getting rid of the effect of oscillation marks with no need of any signal processing. These achievements are promising for the improvement of eddy current testing, in terms of detection sensitivity as well as of rapidity to obtain information.

• Research Organization: IRSID, Saint-Germain-en-Laye (France)
• OSTI ID: 6287065
• Journal Information: J. Nondestr. Eval.; (United States), Journal Name: J. Nondestr. Eval.; (United States) Vol. 6:2; ISSN JNOED
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
42 ENGINEERING
420500* -- Engineering-- Materials Testing
ALLOYS
ANISOTROPY
CRACKS
DEFECTS
DETECTION
EDDY CURRENT TESTING
ELECTRIC IMPEDANCE
ELECTROMAGNETIC FIELDS
ELECTROMAGNETIC TESTING
GEOMETRY
IMPEDANCE
INDUCTION
IRON ALLOYS
IRON BASE ALLOYS
MAGNETIC PROPERTIES
MATERIALS TESTING
MATHEMATICS
NONDESTRUCTIVE TESTING
PHYSICAL PROPERTIES
PROBES
SENSITIVITY
SIGNAL-TO-NOISE RATIO
STEELS
TESTING