| 摘要 |
PURPOSE:To manufacture cold rolled sheet excellent in deep-drawing property, by the hot rolling of steel slab of very low carbon content, cntg. specific quantities of B, Al, N etc. to produce a steel sheet, and by the cold rolling and recrystallization annealing of the steel sheet after it is wound into a coil. CONSTITUTION:A slab of very low carbon content, contg. <0.01% C, <0.05% Si, <0.50% Mn, 0.0025-0.01% B, 0.005-0.05% Al, and N in an amount satisfying a formula: 14/11(B%-0.0005%)<N%<14/11B%+0.0025%, is manufactured by continuous casting. The slab is hot rolled at a finishing temp. not lower than 850 deg.C, and coiled after hot rolling at a temp. not lower than 600 deg.C, the coiling temp., to a composition <=0.0005% solid solution B, and <=0.005% solid solution N. Then the steel sheet is cold rolled at a reduction of area not smaller than 30% to a desired thickness, finally subjected to recrystallization annealing by continuous annealing system, then to 1% skin pass rolling, whereby cold rolled steel sheet excellent in deep-drawing property is manufactured. |
