US3988173A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cold 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 cold 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, 0.003-0.080% 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
2026-11-01 04:05
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/06; C21; C21D; C21D8/00; C21D8/02; C21D8/04; C21D8/0421; C21D8/0426; C21D8/0447; C21D8/0473; C22C38/002
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
128 words
A method for producing an Al-killed cold rolled steel sheet having excellent cold-workability and aging resistance, which comprises hot rolling and cold rolling a steel comprising C ≦ 0.10 % si ≦ 0.10 % Mn ≦ 0.50 % N ≦ 0.008 % sol.Al: 0.003 - 0.080 % B: 0.0020 - 0.0050 % and wherein the ratio B/N is less than 1.0, and the sum (Al + B) is ≦ 20 × N(%), with the balance being iron and unavoidable impurities and then subjecting the thus obtained steel strip to recrystallization annealing at a temperature between 650° C and the A 3 point for not longer than 10 minutes by a continuous annealing method and thereafter cooling the strip at a cooling rate from about 5° to 30° C/sec.
Claim 2
Independent Claim
128 words
A method for producing an Al-killed cold rolled steel sheet having excellent cold-workability and aging resistance, which comprises hot rolling and cold rolling a steel comprising C ≦ 0.10 % si ≦ 0.10 % Mn ≦ 0.50 % N ≦ 0.008 % sol.Al: 0.003 - 0.080 % B: 0.0020 - 0.0050 % and wherein the ratio B/N is less than 1.0, and the sum (Al + B) is ≦ 20 × N(%), with the balance being iron and unavoidable impurities and then subjecting the thus obtained steel strip to recrystallization annealing at a temperature between 650° C and the A 3 point for not longer than 10 minutes by a continuous annealing method and thereafter cooling the strip at a cooling rate from about 5° to 30° C/sec.
Claim 3
Dependent Claim
19 words
The method of claim 1 in which the steel contains not more than 0.02% Si as an unavoidable impurity.
Claim 4
Dependent Claim
23 words
The method of claim 1 in which the carbon content of the steel is reduced to not more than 0.015% by vacuum degassing.
Claim 5
Dependent Claim
15 words
The method of claim 1 in which the steel contains not more than 0.25% Mn.
Claim 6
Dependent Claim
14 words
The method of claim 1 in which the steel contains 0.015 to 0.06% Al.
Claim 7
Dependent Claim
31 words
The method of claim 1 in which the steel contains one or more of 0.01 to 0.08% W, 0.040 to 0.15% P, 0.01 to 0.10% Mo, and 0.01 to 0.08% Nb.
Claim 8
Dependent Claim
23 words
The method of claim 6 in which the carbon content of the steel is reduced to not more than 0.015% by vacuum degassing.
Claim 9
Dependent Claim
15 words
The method of claim 6 in which the steel contains not more than 0.25% Mn.
Claim 10
Dependent Claim
37 words
The method of claim 1 in which the steel strip after the recrystallization annealing and cooling is subjected to an overageing treatment at a temperature between 200° and 500° C for about 10 seconds to 10 minutes.
Claim 11
Dependent Claim
27 words
The method of claim 1 in which the hot rolled steel strip is coiled at a temperature not lower than about 680° C for obtaining better deep-drawability.
Claim 12
Dependent Claim
28 words
The method of claim 1 in which the hot rolled steel strip is coiled at a temperature not higher than about 680° C for obtaining better local-deformation ability.
Claim 13
Dependent Claim
12 words
A cold rolled steel sheet produced by the method of claim 1.
Claim 14
Dependent Claim
12 words
A cold rolled steel sheet produced by the method of claim 6.
References Cited (Backward Citations)
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US3821031A
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US3725143A
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US3839095A
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US3798076A
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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 |