超低碳钢连铸过程中间包覆盖剂结壳机理研究

炼钢 ›› 2023, Vol. 39 ›› Issue (2): 36-41.

超低碳钢连铸过程中间包覆盖剂结壳机理研究

凌海涛1, 2, 3，吴锦圆1，王海军2，常立忠2，仇圣桃2, 4

1.江苏永钢集团有限公司，江苏张家港 215628；
2.安徽工业大学冶金工程学院，安徽马鞍山 243002；
3.北京科技大学钢铁冶金新技术国家重点实验室，北京 100083；
4.钢铁研究总院连铸技术国家工程研究中心，北京 100081

出版日期:2023-04-05 发布日期:2023-04-06

Investigation on the crust mechanism of tundish cover powder during continuous casting of ultra-low carbon steel

Online:2023-04-05 Published:2023-04-06

摘要/Abstract

摘要： 通过工业试验和热力学计算研究了超低碳钢连铸过程中间包覆盖剂成分变化、物相组成以及发生结壳机理。结果表明，RH精炼出站时，钢包顶渣氧化性较高且渣中w(CaO)/w(Al₂O₃)偏低，顶渣成分需要进行改质处理；浇铸过程中由于大包下渣、引流砂的混入以及覆盖剂间相互混合，使得连铸过程中覆盖剂成分发生明显变化；高温下液相中镁铝尖晶石优先生成，促进了钙铝黄长石相和CaO·TiO₂相的形核和长大，进而引起中间包覆盖剂发生结壳。为此，需要严格控制浇铸末期大包下渣，将原始覆盖剂中SiO₂、MgO质量分数分别调整为（10±2.5）%、5.0 %～7.5 %，以抑制钙铝黄长石和镁铝尖晶石相的析出。

关键词: 超低碳钢, 中间包覆盖剂, 结壳机理, 工业试验, 热力学计算

Abstract: The industrial trials and thermodynamic calculation were carried out to investigate the composition evolution, crystallization phase, and crust mechanism of tundish cover powder (TCP) during continuous casting of ultra-low carbon steel. The results showed that the ladle slag had a relatively strong oxidation capacity at RH departure and the w(CaO)/w(Al₂O₃) in the slag was low. The top slag of RH refining needs to be modified. Due to the slag carryover, mix of ladle filler sands and TCP, the composition of TCP during continuous casting has been significantly changed. Furthermore, the MgO·Al₂O₃ spinel in liquid phase was first formed and it promoted the nucleation and growth of 2CaO·Al₂O₃·SiO₂ and CaO·TiO₂ phases, resulting in the crust of TCP. To avoid the crust of TCP during continuous casting, the ladle carryover at cast end should be strictly controlled, and the
mass fraction of SiO₂and MgO in the original TCP are reduced to (10±2.5) % and 5.0 %～7.5 % respectively, which will inhibit the precipitation of 2CaO·Al₂O₃·SiO₂ and MgO·Al₂O₃ spinel phases.

Key words: ultra-low carbon steel, tundish cover powder, crust mechanism, industrial trials, thermodynamic calculation

凌海涛, 吴锦圆, 王海军, 常立忠, 仇圣桃. 超低碳钢连铸过程中间包覆盖剂结壳机理研究[J]. 炼钢, 2023, 39(2): 36-41.

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