关键词: MnS夹杂, 微观组织, 机械性能, 夹杂物改性, 热处理, 工业实践

Abstract: The control of MnS inclusions in steel is a system engineering which involves multiple processes including smelting, solidification, heating and rolling, and requires multi-variable cooperative control. In this paper, the research status of MnS inclusions at home and abroad was discussed in detail, and the influence mechanism of different elements, heat treatment and rolling process on MnS inclusions were expounded. In addition, the current process control measures of MnS inclusions were summarized. The morphology, size and quantity of MnS inclusions can be effectively controlled by adopting appropriate deoxygenation process, improving the oxygen content at the solidification front, reducing the basicity of refining slag, adopting appropriate Ca treatment process, adopting low basicity tundish covering agent, increasing the secondary cooling water volume, strengthening cooling and reducing electromagnetic stirring intensity. In recent years, some new ideas have been proposed to control the deformation treatment and diffusion distribution of MnS inclusions. The morphology, size and quantity of MnS inclusions in steel can be effectively controlled by adding Mg, Ca-Mg, Zr, Ce and Te elements into molten steel.

Key words: MnS inclusions, microstructure, mechanical property, inclusion modification, heat treatment, industrial practice