The paper presents results of FEM modelling as well as properties and microstructure of the ultralow-carbon ferritic steel after the unconventional SPD process—DRECE (dual rolls equal channel extrusion). Based on the conducted numerical simulation information about the deformation behaviour of a steel strip during the DRECE process was obtained. The simulation results were experimentally verified. The influence of DRECE process on hardness distribution, fracture behaviour and microstructure evolution of the investigated steel was analysed. The increase of steel strength properties after subsequent deformation passes was confirmed. The microstructural investigations revealed that the processed strips exhibit the dislocation cell microstructure and subgrains with mostly low-angle grain boundaries. The grains after processing had relatively high dislocation density and intense microband formation was observed. It was also proved that this unconventional SPD method fosters high grain refinement.

本文介绍了非常规SPD工艺DRECE（双辊等径挤压）后的有限元建模结果以及超低碳铁素体钢的性能和显微组织。基于所进行的数值模拟信息，获得了有关DRECE过程中钢带变形行为的信息。仿真结果经过实验验证。分析了DRECE工艺对所研究钢的硬度分布，断裂行为和组织演变的影响。确认在随后的变形通过之后钢强度性能的增加。显微组织研究表明，加工后的带材表现出位错细胞的微观结构和亚晶粒，且大多具有低角度晶界。加工后的晶粒具有较高的位错密度，并且观察到强烈的微带形成。还证明了这种非常规的SPD方法可促进高晶粒细化。