US3619302A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of heat-treating low temperature tough steel
Assignee: Yawata Iron and Steel Co Ltd
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Filing: 1968-11-18
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Granted: 1971-11-09
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Expires: 1988-11-18
Abstract
Abstract Heat-treating method of hot-rolled steel plate containing 1.5% to 10.0% Ni, 0.1% to 5.0% Mn and further at least one element selected from the group consisting of Mo, Cu, Cr, Nb and V, at need and the balance being substantially Fe, comprising subjecting one or more times repeatedly said hot-rolled steel plate to heating to and sequent quenching from a temperature within the range between Ac1 and Ac3 points, then subjecting the steel plate to tempering treatment at a temperature below Ac1 point, thereby to improve largely toughness at low temperature and obtain excellent workability.
Inventors
- 👤 Koichi Aoki
- 👤 Seinosuke Yano
- 👤 Hiroshi Mimura
- 👤 Tohru Inoue
- 👤 Hiroshi Sakurai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:47
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/08; C21; C21D; C21D1/00; C21D1/18; C21D1/185; C22C38/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
46 words
A method according to claim 1, wherein the heat-treatment comprising the heating of the hot-rolled steel plate to a temperature between the Ac1 transformation point and the Ac3 transformation point and the subsequent cooling from the said temperature is carried out repeatedly more than one time.
Claim 2
Dependent Claim
22 words
A method according to claim 2, wherein prior to said heat-treatment, said hot-rolled steel plate is subjected to a solid solution treatment.
Claim 3
Dependent Claim
148 words
A heat-treating method for producing a steel having an excellent toughness at an extremely low temperature and a high strength and good workability from a steel consisting essentially of less than 0.20 wt.% C, 0.05 to 0.40 wt.% Si, 0.10 to 5.0 wt.% Mn, to 1.50 to 10.0 wt.% Ni as basic components, comprising heating a hot-rolled steel plate having the said composition to a temperature below the austenite grain coarsening temperature above the Ac3 transformation point and subsequently cooling the steel plate from the said temperature at least at least at an air-cooling rate, then subjecting the steel plate to a heat-treatment comprising heating the steel plate to a temperature between the Ac1 transformation point and the Ac3 transformation point and subsequently cooling said steel plate from the said temperature at least at an air cooling rate and thereupon tempering the steel plate at a temperature below.
Claim 4
Dependent Claim
53 words
A heat-treating method according to claim 4, wherein the heat-treatment comprising the heating of the steel plate to a temperature between the Ac1 transformation point and the Ac3 transformation point and the subsequent cooling from the said temperature at least at an air cooling rate is carried out repeatedly more than one time.
Claim 5
Dependent Claim
49 words
A heat-treating method according to claim 4 wherein said hot-rolled steel plate is subjected to a solid solution treatment prior to heating the steel plate to a temperature below the austenite grain coarsening temperature above the Ac3 transformation point and subsequently cooling the steel plate from the said temperature.
Claim 6
Independent Claim
61 words
A method as claimed in 1, wherein said steel further comprises at least one element selected from the group consisting of 0.05 to 1.0 wt.% Mo, 0.1 to 2.0 wt.% Cu, 0.1 to 1.50 wt.% C, less than 1.0 wt.% Nb, less than 1.0 wt.% V and less than 0.05 wt.% sol. Al, and the rest being Fe and unavoidable impurities.
Claim 7
Dependent Claim
62 words
A method as claimed in claim 4, wherein said steel further comprises at least one element selected from the group consisting of 0.05 to 1.0 wt.% Mo, 0.1 to 2.0 wt.% Cu, 0.1 to 1.50 wt.% Cr, less than 1.0 wt.% Nb, less than 1.0 wt.% V and less than 0.05 wt.% sol. Al and the rest being Fe and unavoidable impurities.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-08 | 1975-05-10 | 1975-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-08 | 1979-05-10 | 1979-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-08 | 1983-05-10 | 1983-11-09 | $7700.00 | Window Closed / Lapsed |