| 摘要 |
PURPOSE: A method for manufacturing a black plate with superior formability and baking hardness by continuous annealing method, wherein the black plate is used as a material for tin plate and tin free steel used in such products as beverage can, pail can, battery and film case. CONSTITUTION: The manufacturing method of continuous annealing type black plate with superior formability and baking hardness comprises the processes of hot rolling an aluminum killed steel slab comprising 0.003 wt.% or less of C, 0.35 to 0.45 wt.% of Mn, 0.02 to 0.04 wt.% of Zr, other elements inevitably contained in steel and a balance of Fe in an ordinary rolling method; cold rolling the hot rolled slab to a reduction ratio of 87.5 to 90%; continuously annealing the cold rolled slab at a recrystallization temperature or more, that is, in the temperature range of 700 to 720 deg.C; and performing temper rolling on the continuously annealed steel under the ordinary temper rolling conditions so that the manufactured black plate has a hardness of 52 to 58 HR30T, baking hardness, i.e., yield strength after coat printing of the black plate is increased as much as 3 to 4 kgf/mm¬2, and the black plate has 'r' value of 1.7% or more.
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