US4567427A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method non-destructively identifying different kinds of rolled steel for structural purposes
Assignee: Samtec Co Ltd
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Filing: 1983-12-30
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Granted: 1986-01-28
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Expires: 2003-12-30
Abstract
Abstract A method of non-destructively identifying different kinds of rolled steel for structural purposes is disclosed, which is based on a synchronous detection process using a minute AC signal current. Four terminal probes arranged in a row and spaced apart at a precisely uniform pitch are held urged against a measuring surface of steel under test. The signal current is passed through the steel via the opposite end terminal probes. A potential difference is detected between the other two terminal probes. A resistivity corresponding to the detected potential difference is determined, and a corresponding value of silicon content in the steel is determined. The kind of steel is identified according to the determined silicon content.
Inventors
- 👤 Takeo Hattori
- 👤 Tohru Sasakura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:44
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/041; G01N33/00; G01N33/20; G01N33/202; G01N33/2022
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
136 words
A method of non-destructively identifying different kinds of rolled steel for structural purposes comprising the steps of: removing the coating film and/or oxide film of part of the surface of structural rolled steel under test to provide an exposed measuring surface; holding the tips of four resistivity measuring terminal probes in forced contact with said measuring surface in along a straight line and at a uniform interval; passing a current at a low frequency between the opposite end terminal probes in the row; detecting the potential difference between the other two terminal probes than the opposite end terminal probes; determining a resistivity corresponding to said detected potential difference; determining a silicon content of the steel under test according to said determined resistivity; and identifying the kind of the steel under test from said determined silicon content.
Claim 2
Independent Claim
136 words
A method of non-destructively identifying different kinds of rolled steel for structural purposes comprising the steps of: removing the coating film and/or oxide film of part of the surface of structural rolled steel under test to provide an exposed measuring surface; holding the tips of four resistivity measuring terminal probes in forced contact with said measuring surface in along a straight line and at a uniform interval; passing a current at a low frequency between the opposite end terminal probes in the row; detecting the potential difference between the other two terminal probes than the opposite end terminal probes; determining a resistivity corresponding to said detected potential difference; determining a silicon content of the steel under test according to said determined resistivity; and identifying the kind of the steel under test from said determined silicon content.
Claim 3
Dependent Claim
27 words
The method according to claim 1, wherein the allowance of the pitch of arrangement of the tips of said terminal probes is within 1/50 of said pitch.
Claim 4
Dependent Claim
25 words
The method according to claim 1, wherein the frequency of said current passed between said opposite end terminal probes is not higher than 1 kHz.
Claim 5
Dependent Claim
31 words
The method according to claim 1, wherein said detected potential difference between said opposite end terminal probes is coupled to a selective amplifier for selectively amplifying only the signal frequency component.
Claim 6
Dependent Claim
19 words
The method according to claim 4, wherein the output of said eleective amplifier is converted into a corresponding resistivity.
Claim 7
Dependent Claim
11 words
The method according to claim 5, wherein said resistivity is displayed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-01-27 | 1989-07-29 | 1990-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-27 | 1993-07-29 | 1994-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-27 | 1997-07-29 | 1998-01-28 | $7700.00 | Window Closed / Lapsed |