| 摘要 |
PURPOSE: Black plates with excellent formability and ant-aging property suitable for use as pressure vessel and a method for manufacturing the same are provided. CONSTITUTION: The method includes the steps of hot rolling an Al-killed steel comprising 0.004 wt.% or less of C, Mn 0.05 to 0.5 wt.%, Mo 0.1 to 0.3 wt.%, 0.02 wt.% or less of Si, 0.02 wt.% or less of S, soluble Al 0.03 to 0.10 wt.%, N 0.001 to 0.004 wt.%, B 0.001 to 0.003 wt.%, a balance of Fe and incidental impurities at finish hot rolling temperature of 900 to 930 deg.C, wherein atomic ratio of Mo/C is 5 to 15, weight ratio of (B+Al)/N is 15 to 25; coiling the hot rolled Al-killed steel at 580 to 700°C; and continuous annealing it at 640 to 680°C.
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