US4008604A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Determination of carbon analysis in irons
Assignee: Deere and Co
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Filing: 1976-04-07
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Granted: 1977-02-22
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Expires: 1996-04-07
Abstract
Abstract A new, accurate method for the determination of percent total carbon in a molten hypoeutectic or hypereutectic iron is disclosed. It has been found that percent total carbon content of a molten iron is related to a straight-line function of the difference in liquidus and eutectoid transformation (i.e., austenite to pearlite) temperatures of the iron. A standard liquidus - eutectoid transformation temperature difference (based on total carbon content) is generated. A molten iron sample is cooled through the eutectoid transformation temperature and the difference in the liquidus and eutectoid transformation temperatures is compared with the standard liquidus-eutectoid transformation temperature difference to determine the percent total carbon of the sample.
Inventors
- 👤 Maurice P. Roach
- 👤 Ann E. Schoenjahn
- 👤 Larry G. Carmack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:07
CPC Classifications
G; G01; G01N; G01N25/00; G01N25/02; G01N33/00; G01N33/20; G01N33/202; G01N33/2022; G01N33/2025
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
137 words
A method for determining the total carbon content of carbon-containing iron which comprises: allowing samples of molten iron of known total carbon content to cool at least through the first eutectoid transformation temperature; determining the temperature difference between the liquidus and first eutectoid transformation temperature for each of the said samples of known total carbon content; determining a standard liquidus-first eutectoid transformation temperature difference with respect to carbon content; allowing a sample of iron of unknown total carbon content to cool at least through the first eutectoid transformation temperature; determining the liquidus-first eutectoid transformation temperature difference for the said sample of unknown total carbon content; and comparing the resulting liquidus-first eutectoid transformation temperature difference for the sample of unknown total carbon content with the standard liquidus-first eutectoid transformation temperature difference to determine the total carbon content thereof.
Claim 2
Independent Claim
137 words
A method for determining the total carbon content of carbon-containing iron which comprises: allowing samples of molten iron of known total carbon content to cool at least through the first eutectoid transformation temperature; determining the temperature difference between the liquidus and first eutectoid transformation temperature for each of the said samples of known total carbon content; determining a standard liquidus-first eutectoid transformation temperature difference with respect to carbon content; allowing a sample of iron of unknown total carbon content to cool at least through the first eutectoid transformation temperature; determining the liquidus-first eutectoid transformation temperature difference for the said sample of unknown total carbon content; and comparing the resulting liquidus-first eutectoid transformation temperature difference for the sample of unknown total carbon content with the standard liquidus-first eutectoid transformation temperature difference to determine the total carbon content thereof.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein the molten iron is a hypereutectic iron.
Claim 4
Dependent Claim
13 words
The method of claim 1 wherein the molten iron is a hypoeutectic iron.
Claim 5
Independent Claim
68 words
A method for directly determining the percent total carbon of a molten iron sample which comprises cooling said sample; detecting the liquidus and eutectoid temperatures of said cooled sample and obtaining a value representing the difference in said temperatures; and comparing the value obtained with a reference standard of liquidus-eutectoid temperature differences based on percent total carbon content to obtain the percent total carbon of the said sample.
Claim 6
Independent Claim
68 words
A method for directly determining the percent total carbon of a molten iron sample which comprises cooling said sample; detecting the liquidus and eutectoid temperatures of said cooled sample and obtaining a value representing the difference in said temperatures; and comparing the value obtained with a reference standard of liquidus-eutectoid temperature differences based on percent total carbon content to obtain the percent total carbon of the said sample.
Claim 7
Dependent Claim
13 words
The method of claim 4 wherein said molten iron is an unalloyed iron.
Claim 8
Dependent Claim
40 words
The method of claim 5 wherein said reference standard is derived from the equation % Total Carbon = -0.004265 (Δ T) + 7.000 where Δ T is the difference in degrees Fahrenheit between the liquidus temperature and the eutectoid temperature.
Claim 9
Dependent Claim
12 words
The method of claim 4 wherein the iron is a hypoeutectic iron.
Claim 10
Dependent Claim
12 words
The method of claim 4 wherein the iron is a hypereutectic iron.
Claim 11
Dependent Claim
26 words
The method of claim 4 wherein the reference standard is obtained by linear regression analysis of liquidus-eutectoid temperature differences of iron samples of determined carbon content.
Claim 12
Dependent Claim
20 words
The method of claim 4 wherein the reference standard is expressed in the form of a table, chart or graph.
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) | 1980-02-22 | 1980-08-23 | 1981-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-22 | 1984-08-23 | 1985-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-22 | 1988-08-23 | 1989-02-22 | $7700.00 | Window Closed / Lapsed |