The most promising direction for obtaining a unique combination of difficult-to-combine properties of low-carbon steels is the formation of a dispersed ferrite microstructure and a volumetric system of nanoscale phase precipitates. This study was aimed at establishing the special features of the composition influence on the characteristics of the microstructure, phase precipitates, and mechanical properties of hot-rolled steels of the ferritic class. It was carried out by transmission electron microscopy and testing the mechanical properties of metal using 8 laboratory melts of low-carbon steels microalloyed by V, Nb, Ti, and Mo in various combinations. It was found that block ferrite prevails in the structure of steel cooled after hot rolling at a rate of 10–15 °C/s. Lowering of the microalloying components content leads to a decrease in the block ferrite fraction to 20–35% and the dominance of polygonal ferrite. The presence of nanoscale carbide (carbonitride) precipitates of austenitic and interphase/mixed types was detected in the rolled steels. It was established that the tendencies of changes in the characteristics of the structural state and present phase precipitates correlate well with obtained values of strength properties. The advantages of titanium-based microalloying systems in comparison with vanadium-based are shown.

中文翻译：

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化学成分对铁素体类复合微合金钢结构状态和力学性能的影响

获得低碳钢难结合性能的独特组合的最有希望的方向是形成分散的铁素体微观结构和纳米级相沉​​淀物的体积体系。这项研究旨在确定成分对铁素体类热轧钢的组织，相沉淀和力学性能的影响的特殊特征。通过透射电子显微镜进行，并使用由V，Nb，Ti和Mo微合金化的8种低碳钢实验室熔体以各种组合测试了金属的机械性能。发现在热轧后以10–15°C / s的速度冷却后的钢结构中，普遍存在块状铁素体。微合金成分含量的降低导致块状铁素体含量降低至20-35％，并且占据了多边形铁素体的主导地位。在轧制钢中检测到了奥氏体和相间/混合类型的纳米级碳化物（碳氮化物）沉淀物的存在。可以确定的是，结构状态和当前相析出物的特征变化趋势与所获得的强度特性值密切相关。显示了钛基微合金系统与钒基合金相比的优势。可以确定的是，结构状态和当前相析出物的特征变化趋势与所获得的强度特性值密切相关。显示了钛基微合金系统与钒基合金相比的优势。可以确定的是，结构状态和当前相析出物的特征变化趋势与所获得的强度特性值密切相关。显示了钛基微合金系统与钒基合金相比的优势。