CSP工艺生产SPHE钢精炼过程夹杂物的演变  

Evolution of inclusions during refining process of SPHE steel produced by CSP process

作　　者：谯德高[1] 王海东 张乐儒 姚莹 田树坤 于彦冲[2] QIAO Degao;WANG Haidong;ZHANG Leru;YAO Ying;TIAN Shukun;YU Yanchong(Hongxing Iron and Steel Co.,Ltd.,Gansu Jiugang Steel Group,Jiayuguan 735100,Gansu,China;College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China)

机构地区：[1]甘肃酒钢集团宏兴钢铁股份有限公司,甘肃嘉峪关735100 [2]太原理工大学材料科学与工程学院,山西太原030024

出　　处：《中国冶金》2025年第1期61-69,共9页China Metallurgy

基　　金：中央引导地方科技发展资金资助项目(236Z1023G)。

摘　　要：国内某钢厂采用BOF-LF-RH-CSP工艺生产SPHE钢,为控制钢液的洁净度,对SPHE钢精炼过程中夹杂物类型、数量和尺寸的变化规律进行了研究。结果表明,在整个精炼过程中,夹杂物实现了Al_(2)O_(3)→高Al_(2)O_(3)含量的MgO·Al_(2)O_(3)尖晶石→CaS·C_(12)A_(7)·MgO·Al_(2)O_(3)复合夹杂物(C_(12)A_(7)为12CaO·7Al_(2)O_(3))的变质过程。夹杂物数量密度从LF进站的97个/mm^(2)降低至RH出站的12个/mm^(2),平均尺寸由5.2μm逐渐降低至1.5μm,钢液洁净度显著提升。热力学计算结果表明,在1 873 K时,精炼过程中的[Al]质量分数为0.021 6%~0.053 3%时,生成MgO·Al_(2)O_(3)的稳定区间所对应的[Mg]质量分数为0.000 032 3%~0.001 800 0%;RH出站时[Al]质量分数为0.053 3%,当[Ca]质量分数为0.000 24%~0.000 87%时有利于生成液态的12CaO·7Al_(2)O_(3)(C_(12)A_(7));精炼过程中MgO·Al_(2)O_(3)的生成趋势强,其为复合夹杂物CaS·C_(12)A_(7)·MgO·Al_(2)O_(3)的形核核心。通过建立夹杂物演变的动力学模型,揭示了BOF-LF-RH-CSP工艺下精炼过程中夹杂物演变规律。研究结果为提高CSP工艺生产SPHE钢的可浇性提供了数据支撑。SPHE steel is produced by the BOF-LF-RH-CSP process in a domestic steel mill.In order to control the cleanliness of the steel,the changing law of the type,quantity,and size of inclusions in the refining process of SPHE steel was investigated.The results demonstrates that throughout the entire refining process,the inclusions achieve the following modification process,Al_(2)O_(3)→MgO·Al_(2)O_(3) spinel with high Al_(2)O_(3) content→CaS·C_(12)A_(7)·MgO·Al_(2)O_(3) composite inclusions.The number density of inclusions decreases from 97/mm^(2) when entering the LF station to 12/mm^(2) when leaving the RH station.Furthermore,the average size is gradually reduced from 5.2μm to 1.5μm,and the cleanliness of the steel is significantly improved.Thermodynamic calculations at 1873 K show that the[Mg]mass fraction corresponding to the stabilization interval of the generated MgO·Al_(2)O_(3) is 0.0000323%-0.0018000%for the[Al]mass fraction range of 0.0216%-0.0533%in the refining process.Upon entering the RH station,the[Al]mass fraction is 0.0533%.The generation of liquid 12CaO·7Al_(2)O_(3)(C_(12)A_(7))is favored when the[Ca]mass fraction is in the range of 0.00024%-0.00087%.There is a strong tendency to generate MgO·Al_(2)O_(3) during the refining process,which is the nucleation core of CaS·C_(12)A_(7)·MgO·Al_(2)O_(3) composite inclusions.The evolution law of inclusions in the refining process under the BOF-LF-RH-CSP process is revealed by establishing a kinetic model of inclusion evolution.The research results provide data support for improving the castability of SPHE steel produced by the CSP process.

关 键 词：SPHE钢 LF-RH-CSP工艺 精炼 夹杂物演变 热力学 演变机理 

分 类 号：TF769[冶金工程—钢铁冶金]