高速重轨钢生产中的重点和难点之一是MnS非金属夹杂物的控制。稀土元素在许多钢中发挥着独特而且不可替代的重要作用，作为具有稀土资源优势的中国，在属于重要功能材料的重轨钢中稀土的应用还处于起步阶段。本项目以高速重轨钢典型钢种U75V为研究对象，旨在探索稀土元素Ce精确控制U75V钢中MnS夹杂物成分、形状、尺寸、数量、分布和结构的机理。主要内容包括：热力学计算、实验室实验和工业实验；借助的设备主要包括：金相显微镜、扫描电子显微镜、高温激光共聚焦扫描显微镜、真空感应熔炼炉、ASPEX全自动扫描电镜等。通过本项目的开展，为稀土元素精确控制重轨钢中MnS夹杂物提供理论依据与技术支撑。

One of the key and difficult points in high speed rail steel production is the control of MnS nonmetallic inclusions. Rare earth elements play a unique and irreplaceable role in many steel grades. China has obvious advantages in rare earth resources, but the application of rare earth in heavy rail steel which belongs to important functional materials is still in its initial stage. In this project, U75V, a typical steel grade of heavy rail steel, is studied to explore the mechanism of Ce precise control of the composition, shape, size, amount, distribution and structure of MnS inclusions. Thermodynamic calculation, laboratory experiment and industrial experiment are included in the study contents. Metallographic microscope, scanning electron microscope, high temperature laser confocal scanning microscope, vacuum induction melting furnace, ASPEX automatic scanning electron microscope will be used in this study. The theoretical basis and technical support for the precise control of MnS inclusions in heavy rail steel can be obtained through this project.