The structure and mechanical properties of a 09Mn2Si ductile ferritic-pearlitic steel is studied after helical rolling (HR). It is shown that a fine-grained structure is formed in the surface layer about 1 mm deep after every pass of HR accompanied by a gradual temperature decrease in the range 850–500°С, which indicates the development of severe plastic deformation, while in the underlying layers a pronounced textured lamellar structure is formed, consisting of thin elongated ferritic grains oriented along the axis of the rod (in the HR direction). The maximum strengthening of steel is observed in the layer up to 3 mm thick, the minimum – in the near axial (core) zone. Under static tensile testing it is found out that HR results in an increase in the yield strength and a decrease in the elongation at break. The loading diagrams of HR-steel samples contain a sharp yield point and an approximately twice longer yield plateau compared to the initial steel. The experiments on impact loading demonstrate that HR results in larger, by 10–25% on average, KCV values of steel, while at negative temperatures the difference may be as large as 60%.

中文翻译：

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低合金09Mn2Si钢在静动载荷作用下螺旋轧制后的组织和抗应变研究

研究了螺旋轧制（HR）后 09Mn2Si 韧性铁素体-珠光体钢的组织和力学性能。结果表明，每次经过 HR 后，表层都会形成约 1 mm 深的细晶结构，伴随着 850-500°С 范围内的温度逐渐下降，这表明发生了严重的塑性变形，而在下面的层形成了明显的织构层状结构，由沿棒轴（HR 方向）定向的细长铁素体晶粒组成。在厚度达 3 毫米的层中观察到钢的最大强化，在近轴向（核心）区域中观察到最小。在静态拉伸试验中发现 HR 导致屈服强度增加和断裂伸长率降低。与初始钢相比，HR 钢样品的加载图包含一个尖锐的屈服点和大约两倍长的屈服平台。冲击载荷实验表明，HR 导致钢的 KCV 值更大，平均高出 10-25%，而在负温度下，差异可能高达 60%。