Eddy current probe and method for flaw detection in metals

Patent · Tue Jun 23 00:00:00 EDT 1987

OSTI ID:866293

Watjen, John P ^[1]

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1. Sunnyvale, CA

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.

• Research Organization: Ames Laboratory (AMES), Ames, IA; Iowa State Univ., Ames, IA (United States)
• DOE Contract Number: W-7405-ENG-82
• Assignee: SRI International (Menlo Park, CA)
• Patent Number(s): US 4675605
• Application Number: 06/698,369
• OSTI ID: 866293
• Country of Publication: United States
• Language: English

Related Subjects

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/