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Title: Eddy current probe and method for flaw detection in metals

Abstract

A flaw detecting system is shown which includes a probe having a pair of ferrite cores with in-line gaps in close proximity to each other. An insulating, non-magnetic, non-conducting holder fills the gaps and supports the ferrite cores in a manner such that the cores form a generally V-shape. Each core is provided with an excitation winding and a detection winding. The excitation windings are connected in series or parallel with an rf port for connection thereof to a radio frequency source. The detection windings, which are differentially wound, are connected in series circuit to a detector port for connection to a voltage measuring instrument. The ferrite cores at the in-line gaps directly engage the metal surface of a test piece, and the probe is scanned along the test piece. In the presence of a flaw in the metal surface the detection winding voltages are unbalanced, and the unbalance is detected by the voltage measuring instrument. The insulating holder is provided with a profile which conforms to that of a prominent feature of the test piece to facilitate movement of the probe along the feature, typically an edge or a corner. 9 figs.

Inventors:
Issue Date:
OSTI Identifier:
7003194
Patent Number(s):
4675605 A
Application Number:
PPN: US 6-698369
Assignee:
SRI International, Menlo Park, CA (United States) PTO; EDB-94-125139
DOE Contract Number:  
W-7405-ENG-82
Resource Type:
Patent
Resource Relation:
Patent File Date: 5 Feb 1985
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; EDDY CURRENT TESTING; PROBES; METALS; DEFECTS; DESIGN; ELECTRICAL INSULATORS; MATERIALS HANDLING EQUIPMENT; ELECTRICAL EQUIPMENT; ELECTROMAGNETIC TESTING; ELEMENTS; EQUIPMENT; MATERIALS TESTING; NONDESTRUCTIVE TESTING; TESTING; 420500* - Engineering- Materials Testing

Citation Formats

Watjen, J.P. Eddy current probe and method for flaw detection in metals. United States: N. p., 1987. Web.
Watjen, J.P. Eddy current probe and method for flaw detection in metals. United States.
Watjen, J.P. Tue . "Eddy current probe and method for flaw detection in metals". United States.
@article{osti_7003194,
title = {Eddy current probe and method for flaw detection in metals},
author = {Watjen, J.P.},
abstractNote = {A flaw detecting system is shown which includes a probe having a pair of ferrite cores with in-line gaps in close proximity to each other. An insulating, non-magnetic, non-conducting holder fills the gaps and supports the ferrite cores in a manner such that the cores form a generally V-shape. Each core is provided with an excitation winding and a detection winding. The excitation windings are connected in series or parallel with an rf port for connection thereof to a radio frequency source. The detection windings, which are differentially wound, are connected in series circuit to a detector port for connection to a voltage measuring instrument. The ferrite cores at the in-line gaps directly engage the metal surface of a test piece, and the probe is scanned along the test piece. In the presence of a flaw in the metal surface the detection winding voltages are unbalanced, and the unbalance is detected by the voltage measuring instrument. The insulating holder is provided with a profile which conforms to that of a prominent feature of the test piece to facilitate movement of the probe along the feature, typically an edge or a corner. 9 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1987},
month = {6}
}