钢中Al2O3-SiO2-CaO-MnO体系夹杂物变形性能表征及控制基础研究

Al2O3-SiO2-CaO-MnO system oxides are the typical inclusions in high-end Si-Mn killed special steels. Besides of the size, the deformability of inclusions also has great effects on the fatigue resistance and the drawing property of special steels. Controlling the plasticity of non-metallic inclusions in steel is one of the keys to improve the quality of steel. However, the plastic mechanism and the characterization parameter of inclusions are still not clear, leading to the uncertainty in control goals and methods. Thus, it is necessary to carry out the fundamental research on the mechanism and control of the deformability of the aformentioned inclusion system. Firstly, the physical properties of the Al2O3-SiO2-CaO-MnO(-Na2O) system oxides will be summarized and complementally measured to develop the data base of their melting temperature, viscosity, crystalline characteristic, hardness and Young’s modulus. Then the calculation model of the Young’s modulus for a wide temperature domain will be established. The deformation characteristics of inclusions and the evolution mechanism of the inclusions and the cavities on the inclusion-steel interface during the deformation process of steel will also be quasi in-situ analyzed. Finally, the relativity between the deformability and the physical properties of inclusions will be evaluated, accordingly, to propose a more reasonable characterization parameter. And then the inclusion deformability in a wide temperature domain could be controlled by adjusting the parameter. This research will provide a theoretical basis for the optimization of the inclusion control and rolling process of high-end Si-Mn killed special steels.

Al2O3-SiO2-CaO-MnO体系氧化物是高端硅锰脱氧特殊钢中的典型夹杂物类型。除尺寸因素外，夹杂物的变形性能也对特殊钢的抗疲劳性能和拉拔性能影响很大，控制夹杂物变形性能是提升高端特殊钢品质的关键之一。然而夹杂物的形变机制和表征参数还不明确，导致控制目标和手段不明晰，因此很有必要研究该体系夹杂物的变形性能表征及控制。首先总结并补充测定Al2O3-SiO2-CaO-MnO(-Na2O)体系氧化物的物性参数，完善其熔点、粘度、结晶特性、硬度和杨氏模量的数据库，建立适用宽温度域的杨氏模量计算模型；然后通过实验明晰夹杂物的形变特征，并准原位分析钢形变过程中夹杂物和钢-夹杂物界面孔洞的形态演变机制；最后评判夹杂物形变与各参数之间的相关性，据此明确更合理的夹杂物变形性能表征参数，通过表征参数的调控，实现宽温度域内夹杂物变形性能的控制。本研究将为高端硅锰脱氧特殊钢的夹杂物控制工艺和轧制工艺优化提供理论基础。

控制夹杂物变形性能是提升高端特殊钢品质的关键之一。本项目研究了Al2O3-SiO2-CaO-MnO体系夹杂物的变形性能表征及控制。测定和计算了目标夹杂物体系的熔点、粘度、杨氏模量和晶相转变特征，明确了碱度、Na2O含量对夹杂物体系氧化物晶相转变特性的影响规律以及Li2O等氧化物组分对氧化物体系粘度的影响规律。通过数值模拟计算和实验观察，揭示了钢形变过程夹杂物和钢-夹杂物界面的形态演变规律，得到了夹杂物变形性能与夹杂物熔点、粘度、杨氏模量等自身性质参数以及压下量、温度、应变速率等轧制参数之间的关系，确立了粘度/熔点和杨氏模量分别作为高温和低温下夹杂物变形性能的表征参数，为高品质钢中夹杂物的控制目标确立以及塑性化高效控制提供了理论基础和技术指导。出版专著1部，发表SCI期刊论文23篇、中文核心期刊论文11篇、会议论文3篇，授权发明专利7项，获省部级科技奖励一等奖4项。