永磁搅拌作用下含硫非调质钢中MnS的调控机制研究

含硫非调质钢凝固过程中MnS夹杂物沿着枝晶间析出的形态与分布控制，是影响铸坯内部质量和成品力学性能的关键。本项目旨在通过外场手段，在凝固阶段对含硫非调质钢中的MnS进行调控，使其呈细小纺锤状、弥散分布。创新采用旋转永磁体搅拌器（简称永磁搅拌），开展不同参数（磁感应强度、磁体转速、搅拌时间）下铸锭中MnS形态与分布的实验研究以及电磁-传热-流动-溶质的多物理场数值模拟计算；探究永磁搅拌下含硫非调质钢中MnS的演变规律及其与二次枝晶间距、微观偏析和力学性能之间的内在关系；揭示钢液搅拌下的传热、传质、流动对MnS的形核、长大与迁移过程的作用机制；构建永磁搅拌参数/MnS尺寸和数量之间的相关性模型；为含硫非调质钢中MnS的精细化控制和节能高效永磁搅拌的工业化应用提供理论依据与技术支持。

Controlling the size and distribution of MnS precipitation behavior along interdendritic is crucial to the production of sulfur-containing non-quenched and tempered steel due to that MnS inclusions are the key factors affecting the internal quality of billet and the mechanical properties of final products. Our research aims at establish a method of obtaining fine-spindle and dispersively distributed MnS inclusions in sulfur-containing non-quenched and tempered steel during solidification process with physical field. Then, different ingot samples will be prepared by a novel movable permanent magnet stirring (PMS) system under different values of magnetic flux density, rotational speed and stirring period, and a three-dimensional magnetic-temperature-flow-solute field unsteady coupled mathematical model will be established. The evolution of MnS under PMS will be investigated and its relationships with the secondary dendrite arm spacing, microsegregation and mechanical properties will be studied. Besides, the PMS-affected nucleation, growth and movement of MnS will be illuminated by analyzing the quantitative distribution characteristics of the heat and mass transfer and flow behavior of molten steel. Moreover, a model about the relation between the PMS parameters and the size and quantity of MnS will be build. The significance of findings obtained from experimental and simulation are of importance for further control of MnS and industrial application of this innovative technology.