US3582772A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of calibrating eddy current flaw detection equipment utilizing attachable slugs to simulate flaws
Assignee: Republic Steel Corp
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Filing: 1968-11-29
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Granted: 1971-06-01
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Expires: 1988-11-29
Abstract
Abstract A method of calibrating eddy current flaw detection equipment comprises placing one or more metallic slugs in surface contact with a material of a type to be tested. The equipment is adjusted to respond to the presence of the slug or slugs producing electrical indications which are equated to defects of one or more levels of severity.
Inventors
- 👤 Herman J Hammer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:12
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/72; G01N27/82; G01N27/90; G01N27/9073; G01N27/9086
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
131 words
A method of calibrating an eddy current detector for detecting flaws in a metallic workpiece and having circuit means for, upon detection of a flaw, developing an output signal; and variable means coupled to said circuit means for adjusting the value of said output signal, comprising the steps of: a. securing to a surface of said workpiece a metallic slug of predetermined dimensions to thereby simulate a flaw of predetermined dimensions; b. detecting said slug and said workpiece with said eddy current detector and thereby developing an output signal in said circuit means; and, c. adjusting said variable means so that said output sigNal is of substantially the same value as that value which would be developed by a flaw of said predetermined dimensions when detected by said eddy current detector.
Claim 2
Independent Claim
131 words
A method of calibrating an eddy current detector for detecting flaws in a metallic workpiece and having circuit means for, upon detection of a flaw, developing an output signal; and variable means coupled to said circuit means for adjusting the value of said output signal, comprising the steps of: a. securing to a surface of said workpiece a metallic slug of predetermined dimensions to thereby simulate a flaw of predetermined dimensions; b. detecting said slug and said workpiece with said eddy current detector and thereby developing an output signal in said circuit means; and, c. adjusting said variable means so that said output sigNal is of substantially the same value as that value which would be developed by a flaw of said predetermined dimensions when detected by said eddy current detector.
Claim 3
Dependent Claim
19 words
The method of claim 1, wherein said workpiece and said slug have substantially identical magnetic permeabilities and electrical conductivities.
Claim 4
Independent Claim
19 words
The method of claims 1, wherein said workpiece and said slug are of the same material substantially identically treated.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein said slug is secured to said workpiece in good electrical contact therewith.
Claim 6
Dependent Claim
17 words
The method of claim 4, wherein said slug has a thickness of less than approximately 0.010 inch.
Claim 7
Independent Claim
194 words
A method of calibrating an eddy current detector for detecting flaws in a metallic workpiece and having a plurality of channels; each of said channels having circuit means for, upon detection of a flaw, developing an output signal; and variable means coupled to each said circuit means for adjusting the sensitivity of said circuit means so that said channels are responsive to flaws of different magnitudes and comprising the steps of: a. securing to a surface of said workpiece a plurality of metallic slugs of different predetermined dimensions to thereby simulate flaws of different predetermined dimensions; b. detecting said slugs and said workpiece with said eddy current detector and thereby developing output signals in the circuit means of the various channels; and, c. adjusting said variable means in each channel so that the output signal in each channel is respectively developed in response to the presence of one of said slugs of different dimensions and is of substantially the same value as that which would be developed by one of said flaws of different dimensions, when detected by said eddy current detector so that said channels respectively respond to flaws of different predetermined dimensions.
Claim 8
Independent Claim
194 words
A method of calibrating an eddy current detector for detecting flaws in a metallic workpiece and having a plurality of channels; each of said channels having circuit means for, upon detection of a flaw, developing an output signal; and variable means coupled to each said circuit means for adjusting the sensitivity of said circuit means so that said channels are responsive to flaws of different magnitudes and comprising the steps of: a. securing to a surface of said workpiece a plurality of metallic slugs of different predetermined dimensions to thereby simulate flaws of different predetermined dimensions; b. detecting said slugs and said workpiece with said eddy current detector and thereby developing output signals in the circuit means of the various channels; and, c. adjusting said variable means in each channel so that the output signal in each channel is respectively developed in response to the presence of one of said slugs of different dimensions and is of substantially the same value as that which would be developed by one of said flaws of different dimensions, when detected by said eddy current detector so that said channels respectively respond to flaws of different predetermined dimensions.
Claim 9
Dependent Claim
19 words
The method of claim 6, wherein said workpiece and said slugs have substantially identical magnetic permeabilities and electrical conductivities.
Claim 10
Independent Claim
19 words
The method of claims 6, wherein said workpiece and said slugs are of the same material substantially identically treated.
Claim 11
Dependent Claim
16 words
The method of claim 8, wherein said slugs have thicknesses of less than approximately 0.010 inch.
Claim 12
Dependent Claim
16 words
The method of claim 7 wherein said slugs have thicknesses of less than approximately 0.010 inches.
References Cited (Backward Citations)
US2918621A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |