49MnVS非调质钢水口堵塞原因分析
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摘要
非调质钢中含有较多的铝和硫,常在连铸过程中因水口蓄积钙铝酸盐或硫化钙而发生堵塞,影响生产的顺利进行。为了探究非调质钢的水口堵塞原因并提出预防措施,采用X射线荧光分析、X射线衍射分析和热力学计算,分析了非调质钢49MnVS的水口堵塞结瘤物。结果表明,水口堵塞物主要由CaO·6Al_2O_3、CaO·Al_2O_3、MgO·Al_2O_3和金属铁相组成,生产中钙的收得率仅为预期的53.33%;热力学计算表明,水口堵塞的原因是钢液中的钙铝质量比较低,生成了大量高熔点的CaO·6Al_2O_3和CaO·Al_2O_3夹杂物,夹杂物在水口处黏附聚集;同时,由于MgO-C质水口耐火材料被侵蚀,MgO在絮流区与Al_2O_3碰撞生成MgO·Al_2O_3,铁液滴在夹杂物孔隙中凝固黏结,使堵塞物进一步长大,将水口完全堵塞。因此,可以通过优化喂线操作、控制钢中的钙铝比位于0.127～0.225、改进水口材质等措施来预防水口堵塞。
Non-quenched and tempered steel contains high aluminum and sulfur,which often causes the nozzle clogging during continuous casting and hampers the production. In order to explore the cause of the nozzle clogging of nonquenched and tempered steel,and propose preventive measures,the X-ray fluorescence,the X-ray diffraction and the thermodynamic calculation were used to analyze the clogs of the nozzle of 49 MnVS. The results showed that those blockages were mainly CaO?6Al_2O_3,CaO?Al_2O_3,MgO?Al_2O_3and Fe. The calcium yield in the production was only 53.33% of the goal. The thermodynamic calculation indicated that the low ratio of calcium and aluminum caused the nozzle clogging and formed a large amount CaO?6Al_2O_3 and CaO?Al_2O_3 inclusions with a high melting point,which adhered and aggregated at the nozzle. At the same time,the erosion of the MgO-C nozzle leaded to the collision of MgO and Al_2O_3 and formed MgO?Al_2O_3 in turbulent flow zones. The solidification and adhesion of iron droplets in the pore of inclusions caused the growth of blockages and completely blocked the nozzle. Therefore,it is possible to prevent the nozzle clogging by optimizing the feeding operation,controlling the ratio of calcium and aluminum in the range of 0.127 to 0.225 and improving the materials of nozzle.
Non-quenched and tempered steel contains high aluminum and sulfur,which often causes the nozzle clogging during continuous casting and hampers the production. In order to explore the cause of the nozzle clogging of nonquenched and tempered steel,and propose preventive measures,the X-ray fluorescence,the X-ray diffraction and the thermodynamic calculation were used to analyze the clogs of the nozzle of 49 MnVS. The results showed that those blockages were mainly CaO?6Al_2O_3,CaO?Al_2O_3,MgO?Al_2O_3and Fe. The calcium yield in the production was only 53.33% of the goal. The thermodynamic calculation indicated that the low ratio of calcium and aluminum caused the nozzle clogging and formed a large amount CaO?6Al_2O_3 and CaO?Al_2O_3 inclusions with a high melting point,which adhered and aggregated at the nozzle. At the same time,the erosion of the MgO-C nozzle leaded to the collision of MgO and Al_2O_3 and formed MgO?Al_2O_3 in turbulent flow zones. The solidification and adhesion of iron droplets in the pore of inclusions caused the growth of blockages and completely blocked the nozzle. Therefore,it is possible to prevent the nozzle clogging by optimizing the feeding operation,controlling the ratio of calcium and aluminum in the range of 0.127 to 0.225 and improving the materials of nozzle.
引文
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[12]Shin J H,Park J H.Formation mechanism of oxide-sulfide complex inclusions in high-sulfur-containing steel melts[J].Metallurgical and Materials Transactions:B,2017(2):1.
[13]朱万军,王光进,田青,等.钙处理钢水浸入式水口堵塞成因分析[J].武汉科技大学学报,2009,32(5):471.(ZHU Wanjun,WANG Guang-jin,TIAN Qing,et al.Analysis of the cause of clogging of molten steel immersed nozzle[J].Journal of Wuhan University of Science and Technology,2009,32(5):471.)
[14]陈肇友.从相图剖析炉外精炼渣对MgO-CaO系材料的侵蚀[J].金属学报,1983(6):88.(CHEN Yu-you.Analysis of the erosion of MgO-CaO materials by refining slag from the furnace phase diagram[J].Acta Metallurgica Sinica,1983(6):88.)
[2]周蕾,魏刚武,高延祥,等.30MnVS非调质钢的开发[J].钢铁,2017,52(3):76.(ZHOU Lei,WEI Gang-wu,GAO Yan-xiang,et al.Development of 30MnVS non-quenched and tempered steel[J].Iron and Steel,2017,52(3):76.)
[3]惠卫军,刘智雄,张英建,等.一种新型胀断连杆用中碳非调质钢[J].钢铁,2012,47(1):69.(HUI Wei-jun,LIU Zhi-xiong,ZHANG Ying-jian,et al.A new type of medium carbon non quenched and tempered steel[J].Iron and Steel,2012,47(1):69.)
[4]胡芳忠,惠卫军,雍岐龙,等.转向节用贝氏体型非调质钢的高周疲劳性能[J].钢铁,2012,47(7):59.(HU Fang-zhong,HUI Wei-jun,YONG Qi-long,et al.High cycle fatigue properties of bainite non-quenched and tempered steels for steering knuckles[J].Iron and Steel,2012,47(7):59.)
[5]HE Yun-hong.Study on fluidity of non-quenched and tempered steel F45MnVS[J].Shanxi Metallurgy,2017,23(3):7.
[6]Holappa L,Liukkonen M,Liukkonen M,et al.Thermodynamic examination of inclusion modification and precipitation from calcium treatment to solidified steel[J].Ironmaking and Steelmaking,2013,30(2):111.
[7]Abdelaziz S,Megahed G,El-Mahallawi I,et al.Control of Ca addition for improved cleanness of low C,Al killed steel[J]Ironmaking and Steelmaking,2009,36(6):432.
[8]姬旦旦,李富伟,李智,等.含硫非调质钢GS35C-A浇铸性能优化的工艺实践[J].特殊钢,2017,38(4):43.(JI Dan-dan,LIFu-wei,LI Zhi,et al.Process practice of casting performance optimization of sulfur-containing non-tempered steel GS35C-A[J].Special Steel,2017,38(4):43.)
[9]Dekkers R,Blanpain B,Wollants P,et al.A morphological comparison between inclusions in aluminium killed steels and deposits in submerged entry nozzle[J].Steel Research International,2003,74(6):351.
[10]GUO Y T,HE S P,CHEN G J,et al.Improvement in castability of Al containing resulphurised free machining steel[J].Ironmaking and Steelmaking,2014,41(10):738.
[11]Lamut J,Falkus J,Jurjevec B,et al.Influence of inclusions modification on nozzle clogging[J].Archives of Metallurgy and Materials,2012,57(1):319.
[12]Shin J H,Park J H.Formation mechanism of oxide-sulfide complex inclusions in high-sulfur-containing steel melts[J].Metallurgical and Materials Transactions:B,2017(2):1.
[13]朱万军,王光进,田青,等.钙处理钢水浸入式水口堵塞成因分析[J].武汉科技大学学报,2009,32(5):471.(ZHU Wanjun,WANG Guang-jin,TIAN Qing,et al.Analysis of the cause of clogging of molten steel immersed nozzle[J].Journal of Wuhan University of Science and Technology,2009,32(5):471.)
[14]陈肇友.从相图剖析炉外精炼渣对MgO-CaO系材料的侵蚀[J].金属学报,1983(6):88.(CHEN Yu-you.Analysis of the erosion of MgO-CaO materials by refining slag from the furnace phase diagram[J].Acta Metallurgica Sinica,1983(6):88.)