US3988174A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hot rolled steel sheet having excellent workability and method thereof
Assignee: Nippon Steel Corp
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Filing: 1975-07-11
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Granted: 1976-10-26
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Expires: 1995-07-11
Abstract
Abstract A hot rolled steel sheet having excellent cold workability comprising not more than 0.10% of carbon, not more than 0.10% of silicon, not more than 0.50% of manganese, not more than 0.0080% of nitrogen, 0.003-not more than 0.080% of acid-soluble aluminum, 0.0020 - 0.0050% of boron, the balance being iron and unavoidable impurities.
Inventors
- 👤 Tsuyoshi Kawano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:15
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/02; C21D8/04; C21D8/0421; C21D8/0426; C21D8/0447; C21D8/0473; C22; C22C; C22C38/00; C22C38/002; C22C38/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
87 words
A hot rolled steel sheet having excellent cold workability and ageing resistance consisting essentially of not more than 0.10% C, not more than 0.02% Si, not more than 0.50% Mn, not more than 0.008% N, 0.003 to 0.08% sol. A1, 0.0020 to 0.0050% B with the balance being Fe and unavoidable impurities, in which 2.7 [N%] ≦ (A1 + B) ≦ 20 [N%], the ratio of B/N is less than 1.0 and wherein the sheet has a grain size number not larger than No. 9 of ASTM.
Claim 2
Dependent Claim
87 words
A hot rolled steel sheet having excellent cold workability and ageing resistance consisting essentially of not more than 0.10% C, not more than 0.02% Si, not more than 0.50% Mn, not more than 0.008% N, 0.003 to 0.08% sol. A1, 0.0020 to 0.0050% B with the balance being Fe and unavoidable impurities, in which 2.7 [N%] ≦ (A1 + B) ≦ 20 [N%], the ratio of B/N is less than 1.0 and wherein the sheet has a grain size number not larger than No. 9 of ASTM.
Claim 3
Dependent Claim
16 words
The sheet of claim 1 in which the sol. A1 content is from 0.015 to 0.06%.
Claim 4
Dependent Claim
15 words
The sheet of claim 1 in which the manganese content is not more than 0.25%.
Claim 5
Dependent Claim
36 words
The sheet of claim 1 which further contains one or more elements selected from the group consisting of Zr, Ca, Mg and REM elements in an amount between 0.01 and 0.20% in single or in total.
Claim 6
Dependent Claim
14 words
The sheet of claim 1 in which the carbon content is less than 0.010%.
Claim 7
Dependent Claim
20 words
The steel sheet of claim 1 wherein acid soluble aluminum is present in an amount sufficient to kill the steel.
Claim 8
Dependent Claim
66 words
The sheet of claim 1 which further contains one or more elements selected from the group consisting of Zr, Ca, Mg and REM elements in an amount of 0.01 to 0.20% in single or in total and one or more elements selected from the group consisting of Ti, Cr, V, Nb, Mo and W in an amount of 0.01 to 0.10% in single or in total.
Claim 9
Dependent Claim
21 words
The sheet of claim 1 in which the manganese is not more than 0.25% and less than 0.010% S is present.
Claim 10
Dependent Claim
61 words
In a method for producing sheet of claim 1 wherein a slab is prepared by conventional methods and the slab is hot rolled, the improvement which comprises hot rolling the slab at a finishing temperature not lower than the Ar 3 temperature and coiling the sheet at coiling temperature not higher than 680° C so as to avoid coarsening of carbides.
Claim 11
Dependent Claim
41 words
The method according to claim 9 in which the slab is rolled at a temperature between 1150° and 1050° and the total reduction in that temperature range is at least 40% on the basis of the plate thickness at 1150° C.
References Cited (Backward Citations)
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US3666452A
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US3821031A
Cited
US3725143A
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US3839095A
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US3798076A
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US3765874A
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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) | 1979-10-26 | 1980-04-26 | 1980-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-26 | 1984-04-26 | 1984-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-26 | 1988-04-26 | 1988-10-26 | $7700.00 | Window Closed / Lapsed |