| 摘要 |
PURPOSE:To produce a steel sheet of superior aging resistance and workability by hot rolling and cold rolling a continuously cast slab of low-carbon steel added with a specific ratio of B based on the content of N then annealing the same. CONSTITUTION:Molten low-carbon steel contg. 0.02-0.10% C, <0.03% Si, <0.25% Mn, <0.01% Sol. Al, <0.010% O, <0.0050% N, and 0.003-0.010% B, and of >=1.0 in the ratio of B/N is produced by utilizing a degassing treatment method. This molten steel is continuously cast to a slab which is then hot rolled and is next finish rolled at temperature above the A3 transformation point, after which the sheet is wound to a coil at 500-750 deg.C. This hot rolled sheet is cold rolled at 30-90% drafts and is annealed at temperature above the recrystallization temperature by batch annealing or continuous annealing. The N is the steel deposites perfectly as BN, and the steel sheet of superior aging resistance and superior workability resulted by low C, and low Si is obtained. |
