提供了优良的板厚及其制造方法的中心部分的强度和韧性厚和高韧性高强度钢。 微观结构在整个厚度方向上的平均50μm以下旧奥氏体粒径，马氏体和/或贝氏体的面积分数为80％以上的具有特定化学组成，厚钢板。 特定成分组合物的连续铸造扁坯，加热至1200℃〜1350℃后，进行热加工，以应变速率累积压下率为15％或更多或更少的3 / s，则热轧，热处理 这样做。

To provide a thick and high toughness high-tensile steel sheet excellent in strength and toughness of the plate thickness center and a method of manufacturing the same.
Microstructure over the entire thickness direction, the average 50μm or less at prior austenite grain size, the area fraction of martensite and / or bainite of 80% or more, thick steel sheet having a specific chemical composition. The continuously cast slab of the specific component composition, after heating to 1200 ° C. to 1350 ° C., subjected to hot working to strain rate cumulative rolling reduction of 15% or more below 3 / s, then, hot-rolled, heat-treated do.