| 摘要 |
PURPOSE:To produce a non-refined high tensile steel plate of high toughness and hydrogen-induced cracking resistance by heating, blooming and cooling a steel ingot or slab under specific conditions and further reheating, and hot rolling the same then allowing the plate to cool. CONSTITUTION:After a steel ingot or slab is heated to 1,150 deg.C, it is bloomed down to intermediate thickness at a 650-800 deg.C finishing temp. range in such a way that the draft is >=30%. Thence, it is once cooled to temp. below 650 deg.C, and is reheated to 800-950 deg.C, after which it is rolled by the hot rolling of >=30% total draft at 690-740 deg.C finishing temps. of the hot rolling at 30% draft, thence it is allowed to cool. The kind of the steel adapted in this is killed steel or semi-killed steel consisting basically of, for example, 0.05-0.30% C, <=0.70% Si, 0.3-1.6% Mn, and <=0.07% SolAl, and contains 1 or >=2 kinds of 0.02- 0.30% V, 0.005-0.20% Nb, 0.010-0.10% Ta or <=0.0015% Al, N. |
