On the example of industrial continuously-cast slabs 355 mm thick of two steels of different chemical compositions recommended for the production of thick heavy plates of quality categories S355ML according to EN 10025-4:2019 and S355NL according to EN 10025-3:2019 features of structure formation and their potential effect on low-temperature impact energy of a continuously cast slab are studied. Macro-and microstructural conditions are studied, the quantitative composition of structural components is calculated, the point of the ternary junction is determined, and values of low-temperature impact energy at 1/8, 1/4 and 1/2 of the slab thickness, 1/4 and 1/2 of the slab width are obtained, and the transition temperature for entirely brittle failure is established. Fractographic analysis is conducted, fracture structure is described, and non-metallic inclusions are identified. Individual examples of the possible inheritance of structural inhomogeneity from slab to thick sheet are illustrated.

以 355 毫米厚的工业连铸板坯为例，推荐用于生产符合 EN 10025-4:2019 质量类别 S355ML 和符合 EN 10025-3:2019 质量类别 S355NL 的厚厚板，其化学成分不同研究了组织形成的过程及其对连铸板坯低温冲击能的潜在影响。研究宏观和微观组织条件，计算结构成分的定量成分，确定三元结点，得出板坯厚度1/8、1/4、1/2处的低温冲击功值、 1/4 和 1/2 板坯宽度，并建立了完全脆性破坏的转变温度。进行断口分析，描述断口结构，并识别非金属夹杂物。举例说明了从板坯到厚板的结构不均匀性可能继承的个别例子。