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Patent US4388122A successfully refreshed from Google Patents.
US4388122A
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US
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Method of making high strength hot rolled steel sheet having excellent flash butt weldability, fatigue characteristic and formability
Assignee: Kobe Steel Ltd
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Filing: 1981-08-03
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Granted: 1983-06-14
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Expires: 2001-08-03
Abstract
Abstract A high strength hot rolled steel sheet having excellent flash butt weldability, fatigue characteristic and formability, has a composite structure composed of polygonal ferrite and bainite and containing from 0.01 to 0.15% by weight of C, from 0.01 to 1.5% by weight of Si and from 0.3 to 2.0% by weight of Mn, the rest being Fe and impurities, the areal ratio of the bainite being from 3 to 60%. The steel sheet is suitable as a material for wheel rims or discs for automobiles.
Inventors
- 👤 Masatoshi Sudo
- 👤 Shunichi Hashimoto
- 👤 Shoji Kambe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:43
CPC Classifications
C; C22; C22C; C22C38/00; C21; C21D; C21D1/00; C21D1/02; C21D8/00; C21D8/02; C21D8/0221; C21D8/0226; C21D2211/00; C21D2211/002; C21D2211/005; C21D2211/008
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
134 words
A method of producing high strength, hot rolled, steel sheet with excellent flash butt weldability, fatigue characteristic and formability, having a composite structure consisting of polygonal ferrite and bainite, and containing from 0.01 to 0.15% by wt of C, from 0.01 to 1.5% by wt of Si, and from 0.3 to 2.0% by wt of Mn, the area ratio of the bainite being from 3 to 60%, said steel sheet being produced by a cooling treatment consisting of: upon completion of the hot rolling, cooling the hot rolled steel sheet for 3 to 20 seconds at a cooling rate of 4° to 10° C./sec; thereafter cooling the steel sheet at a cooling rate of 50° to 100° C./sec, and winding up the sheet thus cooled at a temperature of from 350° to 575° C.
Claim 2
Independent Claim
134 words
A method of producing high strength, hot rolled, steel sheet with excellent flash butt weldability, fatigue characteristic and formability, having a composite structure consisting of polygonal ferrite and bainite, and containing from 0.01 to 0.15% by wt of C, from 0.01 to 1.5% by wt of Si, and from 0.3 to 2.0% by wt of Mn, the area ratio of the bainite being from 3 to 60%, said steel sheet being produced by a cooling treatment consisting of: upon completion of the hot rolling, cooling the hot rolled steel sheet for 3 to 20 seconds at a cooling rate of 4° to 10° C./sec; thereafter cooling the steel sheet at a cooling rate of 50° to 100° C./sec, and winding up the sheet thus cooled at a temperature of from 350° to 575° C.
Claim 3
Independent Claim
152 words
A method of producing high strength, hot rolled, steel sheet with excellent flash butt weldability, fatigue characteristics and formability, having a composite structure consisting of polygonal ferrite and bainite, and containing from 0.01 to 0.15% C, from 0.01 to 1.5% by wt of Si and from 0.3 to 2.0% by wt of Mn, the area ratio of the bainite being from 3 to 60%, said steel sheet being produced by a cooling treatment consisting of: upon completion of the hot rolling, cooling the hot rolled steel sheet for 1 to 10 seconds at a cooling rate of 20° to 50° C./sec; then gradually cooling the steel sheet for 3 to 20 seconds at a cooling rate of 4° to 10° C./sec; thereafter, rapidly cooling the steel sheet at a cooling rate of 50° to 100° C./sec, and winding up the sheet thus cooled at a temperature of from 350° to 575° C.
Claim 4
Independent Claim
152 words
A method of producing high strength, hot rolled, steel sheet with excellent flash butt weldability, fatigue characteristics and formability, having a composite structure consisting of polygonal ferrite and bainite, and containing from 0.01 to 0.15% C, from 0.01 to 1.5% by wt of Si and from 0.3 to 2.0% by wt of Mn, the area ratio of the bainite being from 3 to 60%, said steel sheet being produced by a cooling treatment consisting of: upon completion of the hot rolling, cooling the hot rolled steel sheet for 1 to 10 seconds at a cooling rate of 20° to 50° C./sec; then gradually cooling the steel sheet for 3 to 20 seconds at a cooling rate of 4° to 10° C./sec; thereafter, rapidly cooling the steel sheet at a cooling rate of 50° to 100° C./sec, and winding up the sheet thus cooled at a temperature of from 350° to 575° C.
Claim 5
Dependent Claim
20 words
The method according to claim 1 or 2, wherein the area ratio of the bainite is from 5 to 30%.
Claim 6
Dependent Claim
14 words
The method according to claim 1 or 2, wherein the bainite is upper bainite.
Claim 7
Dependent Claim
12 words
The method according to claim 4, wherein the bainite is upper bainite.
Claim 8
Dependent Claim
22 words
The method according to claim 1 or 2, wherein the steel sheet further contains from 0.01 to 1.5% by wt of Cr.
Claim 9
Dependent Claim
56 words
The method according to claim 1 or 2, wherein the steel sheet further contains at least one member selected from the group consisting of from 0.01 to 0.08% by wt of Nb, from 0.02 to 0.6% by wt of V, from 0.01 to 0.08% by wt of Ti, and 0.02 to 0.18% by wt of Zr.
Claim 10
Dependent Claim
41 words
The method according to claim 1 or 2 wherein the steel sheet further contains at least one member selected from the group consisting of from 0.05 to 0.2% by wt of Mo and from 0.0005 to 0.005% by wt of B.
Claim 11
Dependent Claim
49 words
The method according to claim 1 or 2, wherein the steel sheet further contains at least one member selected from the group consisting of from 0.1 to 0.5% by wt of Ni, from 0.1 to 0.5% by wt of Cu and from 0.02 to 0.15% by wt of P.
Claim 12
Dependent Claim
52 words
The method according to claim 1 or 2, wherein the steel sheet further includes at least one member selected from the group consisting of from 0.0005 to 0.01% by wt of Ca, from 0.0005 to 0.01% by wt of Mg and from 0.005 to 0.1% by weight of a rare earth element.
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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) | 1986-06-13 | 1986-12-13 | 1987-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-13 | 1990-12-13 | 1991-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-13 | 1994-12-13 | 1995-06-14 | $7700.00 | Window Closed / Lapsed |