方坯连铸永磁搅拌技术的发展现状与展望

电磁搅拌已经成为连铸工艺中改善铸坯质量的重要技术手段。相较于传统的三相交流电磁搅拌(EMS),基于烧结钕铁硼材料的旋转永磁体搅拌(PMS)具有磁感应强度较大、电能消耗低、结构较简单等优点。主要对比了电磁搅拌和永磁搅拌的技术特点,介绍了永磁搅拌在方坯连铸结晶器和凝固末端的应用现状;结晶器内永磁搅拌有效改善了铸坯的表面和内部质量,表面小孔缺陷明显减少,改善铸坯中心疏松和中心碳偏析;而应用于高碳钢连铸凝固末端,随着永磁搅拌磁体转速的增加,铸坯中心碳偏析指数明显降低,同时吨钢电能消耗仅约为传统电磁搅拌的15%。

Present situation and prospect of permanent magnet stirring during billet continuous casting

Electromagnetic stirring has become an important technique to improve billet quality in continuous casting process. Compared with the traditional three-phase AC electromagnetic stirring (EMS), the permanent magnet stirring (PMS) based on sintered NdFeB material has the advantages of higher magnetic induction intensity, lower power consumption and simpler structure. The technical characteristics of electromagnetic stirring and permanent magnet stirring are compared and the present application situation of mold and final permanent magnet stirring during billet continuous casting is introduced. It was reported that the mold permanent magnet stirring can effectively improve the surface and internal quality of the billet, reduce the hole defects on the surface, and improve the central porosity and central carbon segregation of the billet. In addition, permanent magnet stirring was applied in the final solidification position of high carbon steel continuous casting rectangular billet. It was found that the center carbon segregation index of the billet decreases obviously with the increase of the rotating speed of PMS, and the energy consumption of PMS per ton of steel was only about 15% of that of traditional EMS.