为扩展镁处理在硅锰脱氧钢体系中的应用，采用高温模拟试验与热力学分析相结合的方法，考察了镁添加量及镁添加顺序对夹杂物生成及演变行为的影响。研究结果表明，Mg-Si-Mn-O钢液体系在1 600 ℃时存在MgO-SiO2-MnO（l）、2MgO·SiO2（s）和MgO（s） 3个热力学稳定区域。镁处理可有效改变SiO2-MnO脱氧产物，低镁加入量（0.000 5%）下生成MgO-SiO2-MnO液相夹杂物，高镁加入量（0.001 9%）下生成MgO固相夹杂物。硅和镁的加入顺序不同导致夹杂物的生成路径也不相同，先硅后镁时夹杂物生成路径为SiO2-MnO（l）→MgO-SiO2-MnO（l），而先镁后硅时夹杂物的演变过程为MgO（s）→MgO-SiO2（s）→MgO-SiO2-MnO（l）。

In order to expand the application of magnesium treatment in the Si-Mn killed steel production， the effect of the amount and the order of addition magnesium on the formation and the evolution of inclusion were investigated by the combination of high temperature experiments and thermodynamic calculations. The results showed that the stability diagram of the Mg-Si-Mn-O molten steel at 1 600 ℃ was composed of MgO-SiO2-MnO（l）， 2MgO·SiO2（s） and the MgO（s）. The deoxidization product of the SiO2-MnO（l） was modified to MgO-SiO2-MnO（l） when the addition amount of magnesium was 0.000 5%. When the addition amount of the magnesium increased to 0.001 9%， MgO（s） phase formed.The formation path of inclusions varied with different orders of addition magnesium. When magnesium was added following the silicon addition， the formation path was SiO2-MnO（l）→MgO-SiO2-MnO（l）. While the evolution path was MgO（s）→MgO-SiO2（s）→MgO-SiO2-MnO（l） when magnesium was added before addition silicon.