| 摘要 |
PURPOSE: Provided is a process for preparing a surface treated plate by using ultra low carbon aluminium-killed steel, controlling an amount of zirconium alone to be added or an atom ratio with N and S, annealing and hardening materials in a baking process after drawn and ironing process. Whereby, the obtained plate having excellent processability at an annealing temperature of low temperature and pressure-proof characteristic can be used as material steel plate for 2-piece vessel. CONSTITUTION: The plate comprises C:0.002 to 0.005wt.%, S:0.012wt.% or less, N:0.003wt.% or less, Mn:0.05 to 0.20wt.%, Al:0.03 to 0.06wt.%, Zr:0.005 to 0.025wt.% and the balance:Fe and other inevitable elements. Aluminium-killed steel containing the above composition is homogenized at 1,200 to 1,250deg.C, hot rolled at 900 to 930deg.C, reeled at 620 to 700deg.C, cold rolled at a reduction ratio of 85 to 90%; and continuously annealed in the range of low temperature annealing temperature of 650 to 720deg.C to produce the titled plate.
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