Method for manufacturing a steel sheet
US6818079B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 2003 |
| Grant date | Nov 16, 2004 |
| Priority date | — |
| Expiry date | May 27, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D8/021
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method for manufacturing a steel sheet comprising continuously casting a steel containing 0.04 to 0.2 wt. % C, 0.25 to 2 wt. % Si, 0.5 to 2.5 wt. % Mn, and 0.1 wt. % or less Al to form a slab; hot-rolling by rough-rolling the slab to form a sheet bar and finish-rolling the sheet bar with a reduction in thickness at the final stand of less than 30%, the finish-rolling being completed at a temperature from the Ar3 transformation point to the Ar3 transformation point +60° C.; primary-cooling the hot-rolled steel sheet, the primary cooling being started within 1 second after the completion of hot-rolling and conducting the cooling at a cooling speed of higher than 200° C./sec down to a temperature of Ar3 −30° C. to the Ar1 transformation point; slow cooling or air-cooling the primary-cooled steel sheet at a temperature of the Ar3 transformation point to the Ar1 transformation point at 10° C./sec or less for 2 seconds or more; secondary-cooling the steel sheet after the slow cooling or the air-cooling at 30° C./sec or more; and coiling the secondary-cooled steel sheet at 300° C. or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.