20SiMn合金结构钢精炼渣系优化  

Optimization of refining slag of 20SiMn alloy structural steel

作　　者：成日金[1,2] 齐詹 张华[1,2] 刘成松[1,2] 倪红卫[1] CHENG Ri-jin;QI Zhan;ZHANG Hua;LIU Cheng-song;NI Hong-wei(The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China)

机构地区：[1]武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉430081 [2]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,湖北武汉430081

出　　处：《钢铁》2023年第1期100-107,152,共9页Iron and Steel

基　　金：国家自然科学基金联合基金重点资助项目(U21A20113);湖北省教育厅科学技术研究计划资助项目(B2020004)。

摘　　要：为控制20SiMn锻件用结构钢中氧含量和钢中夹杂物,首先采用热力学软件FactSage 8.1计算了1600℃下CaO-SiO_(2)-Al_(2)O_(3)-5%MgO系精炼渣与20SiMn钢液平衡时的等氧线,并优化了精炼渣成分。同时,计算了不同氧含量下钢中Fe-Mg-Al-O体系优势区图。其次,实验室中设计了4组精炼渣成分,并在1600℃下采用高温电阻炉进行渣-钢平衡试验,试验后采用X射线荧光光谱分析测定渣成分,采用等离子体光谱仪对钢样成分进行分析,采取红外碳硫分析仪、氧氮联合分析仪分别测定钢中碳硫和全氧含量,采用场发射扫描电子显微镜对试样中的夹杂物进行成分和形貌分析,并对钢中夹杂物数量与成分进行统计,试验研究了不同精炼渣对钢中氧含量、夹杂物组成、数量和尺寸的影响。最后,建立了动力学模型来描述“钢渣”界面上的夹杂物去除行为。试验和热力学模型结果揭示了钢中典型Al_(2)O_(3)、MgO·Al_(2)O_(3)夹杂物与钢中氧、镁和铝含量的关系,动力学模型描述了夹杂物分离率、全氧含量与整体润湿性之间的对应关系。优化渣系中SiO_(2)、CaO、Al_(2)O_(3)和MgO质量分数分别为0~24.7%、44.3%~55.1%、20.5%~48.2%和5%~8%时,可控制钢中溶解氧质量分数为0.0005%内;典型成分50.4%CaO-40.3%Al_(2)O_(3)-4.3%SiO_(2)-5%MgO渣系可将钢中总氧质量分数和夹杂物数量分别控制为0.00142%和9.9个/mm^(2),试验与模型预测结果基本一致。In order to control the[O]content and inclusions in 20SiMn structural steel for forgings,firstly,the iso-oxygen line of CaO-SiO_(2)-Al_(2)O_(3)-5%MgO refining slag in equilibrium with 20SiMn liquid steel at 1600℃were calculated by using thermodynamic software FactSage 8.1,and the composition of refining slag was optimized.At the same time,the dominant area diagram of Fe-Mg-Al-O system in steel with different oxygen content was calculated.Secondly,four groups of refining slag components were designed in the laboratory,and the slag-steel equilibrium experiments were carried out in a high-temperature resistance furnace at 1600℃.After the test,the slag components were determined by X-ray fluorescence spectrometry,and the composition of the steel samples were analyzed by inductively coupled plasma optical emission spectrometer,infrared carbon sulfur analyzer and oxygen nitrogen combined analyzer.The composition and morphology of inclusions in the sample were analyzed by field emission scanning electron microscope,and the number and composition of inclusions in steel were counted.The effects of different refining slags on the oxygen content,composition,number and size of inclusions in steel were experimentally studied.Finally,a dynamic model was established to describe the inclusion removal behavior on the"steel-slag"interface.The experimental and thermodynamic model results reveal the relationship between typical Al_(2)O_(3)and MgO·Al_(2)O_(3)inclusions in steel and the contents of oxygen,magnesium and aluminum in steel.The kinetic model describes the corresponding relationship between inclusion separation rate,total oxygen content and overall wettability.When the contents of CaO,SiO_(2),Al_(2)O_(3)and MgO in the optimized slag system are 0-24.7%,44.3%-55.1%,20.5%-48.2%and 5%-8%respectively,the dissolved oxygen in steel can be controlled within 0.0005%.The slag system with typical composition of 50.4%CaO-40.3%Al_(2)O_(3)-4.3%SiO_(2)-5%MgO can control the amount of T[O]and impurities in steel at 0.00142%and 9.9 pi

关 键 词：20SiMn钢 精炼渣 非金属夹杂物 热力学 动力学模型 

分 类 号：TF769[冶金工程—钢铁冶金]