重轨钢凝固和冷却过程中非金属夹杂物生成热力学及工业实践  

Thermodynamics and industrial practice of non-metallic inclusions of heavy rail steel during solidification and cooling

作　　者：辛广胜[1] 储焰平 任英[3] 谌智勇[1] 刘南[1,3] 黄日康 XIN Guangsheng;CHU Yanping;REN Ying;CHEN Zhiyong;LIU Nan;HUANG Rikang(Steelmaking Plant,Inner Mongolia Baotou Steel Union Co.,Ltd.,Baotou 014010,China;Steelmaking Branch,WISDRI Engineering&Research Incorporation Ltd.,Wuhan 430223,China;School of Metallurgical and Ecological Engineering,University of Science and Technology Beiing,Beijing 100083,China)

机构地区：[1]内蒙古包钢钢联股份有限公司炼钢厂,内蒙古包头014010 [2]中冶南方工程技术有限公司炼钢分公司,湖北武汉430223 [3]北京科技大学冶金与生态工程学院,北京100083

出　　处：《炼钢》2020年第4期39-47,共9页Steelmaking

基　　金：国家自然科学基金资助项目(U186026、51725402);中央高校基本科研业务费专项资金(FRF-TP-17-001C2)。

摘　　要：为了研究钢液凝固和冷却过程中非金属夹杂物的生成热力学,以U75V重轨钢为研究对象,通过Aspex自动扫描电镜对不同钢液成分的中间包钢水样和连铸坯样进行分析,结合热力学计算,得到了重轨钢凝固和冷却过程中夹杂物的转变机理。研究结果表明,重轨钢中间包内主要为CaO-SiO2-Al2O3-MgO型夹杂物,且夹杂物成分均匀;凝固冷却过程不仅导致夹杂物成分的变化,也会导致相的不均匀性,连铸坯中的夹杂物为CaO-SiO2-Al2O3-MgO-CaS型,夹杂物中CaO含量降低,CaS含量升高,凝固冷却后的夹杂物由CaS、MgO·Al2O3以及CaO-SiO2-Al2O3-MgO等多相组成,其中MgO·Al2O3相位于CaO-SiO2-Al2O3-MgO相内部,最外层包裹CaS。热力学计算结果与试验结果基本吻合,夹杂物成分差异可能由于热力学和动力学条件不足引起。U75 V heavy rail steel was used in present work to investigated the transformation of inclusions during solidification and cooling of molten steel. Steel samples with varied chemical compositions were taken from blooms and molten steel of tundish,which was analyzed by the Aspex automatic scanning electron microscope,combined with thermodynamic calculation,the transformation mechanism of inclusions in the solidification and cooling process of heavy rail steel was obtained. The results show that inclusions in molten steel of tundish were mainly CaO-SiO2-Al2O3-MgO type,which was uniform in chemical compositions.During solidification and cooling,not only the composition of inclusions changed,but also the heterogeneity of phase. The inclusions in blooms were CaO-SiO2-Al2O3-MgO-CaS type with the content of CaO reduced in inclusions,while that of CaS increased,and the inclusions that showed a multi-phase structure were mainly composed of phases such as CaS,MgO·Al2O3 and CaO-SiO2-Al2O3-MgO,in which the MgO·Al2O3 phase located inside the CaO-SiO2-Al2O3-MgO phase,and CaS wrapped outside. Thermodynamic calculation results are basically consistent with the experimental ones,and the difference in inclusion compositions may be attributed to the insufficient thermodynamic and kinetic conditions.

关 键 词：重轨钢 夹杂物 凝固冷却 转变 

分 类 号：TF777.2[冶金工程—钢铁冶金]