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US 3,988,173 AGranted
Cold rolled steel sheet having excellent workability and method thereof
AssigneeNippon Steel Corporation
InventorTsuyoshi Kawano
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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.
Claims13
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 .ltoreq. 0.10 %
- si .ltoreq. 0.10 %
- Mn .ltoreq. 0.50 %
- N .ltoreq. 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 .ltoreq. 20 .times. 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.degree. C and the A.sub.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.degree. to 30.degree. C/sec.
6 more elements
Dependencies are inferred from the claim text.