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.
- Inventors:
-
- Sunnyvale, CA
- Issue Date:
- Research Org.:
- Ames Laboratory (AMES), Ames, IA; Iowa State Univ., Ames, IA (United States)
- OSTI Identifier:
- 866293
- Patent Number(s):
- 4675605
- Application Number:
- 06/698,369
- Assignee:
- SRI International (Menlo Park, CA)
- Patent Classifications (CPCs):
-
G - PHYSICS G01 - MEASURING G01N - INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- DOE Contract Number:
- W-7405-ENG-82
- Resource Type:
- Patent
- Country of Publication:
- United States
- Language:
- English
- Subject:
- eddy; current; probe; method; flaw; detection; metals; detecting; shown; pair; ferrite; cores; in-line; gaps; close; proximity; insulating; non-magnetic; non-conducting; holder; fills; supports; manner; form; v-shape; core; provided; excitation; winding; windings; connected; series; parallel; rf; connection; radio; frequency; source; differentially; wound; circuit; detector; voltage; measuring; instrument; directly; engage; metal; surface; piece; scanned; presence; voltages; unbalanced; unbalance; detected; profile; conforms; prominent; feature; facilitate; movement; typically; edge; corner; measuring instrument; metal surface; eddy current; close proximity; radio frequency; voltage measuring; flaw detection; frequency source; current probe; ferrite core; series circuit; facilitate movement; /324/
Citation Formats
Watjen, John P. Eddy current probe and method for flaw detection in metals. United States: N. p., 1987.
Web.
Watjen, John P. Eddy current probe and method for flaw detection in metals. United States.
Watjen, John P. Tue .
"Eddy current probe and method for flaw detection in metals". United States. https://www.osti.gov/servlets/purl/866293.
@article{osti_866293,
title = {Eddy current probe and method for flaw detection in metals},
author = {Watjen, John 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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jun 23 00:00:00 EDT 1987},
month = {Tue Jun 23 00:00:00 EDT 1987}
}