VD过程钢渣混卷行为的水模型
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摘要
通过水模型研究了VD精炼过程的钢渣混卷行为,定义了钢渣临界半混和临界全混状态,并对不同底吹气量、真空度、底吹位置下的混合状态进行了研究;分析了临界搅拌功率和流场稳定性对混卷行为的影响.结果表明:在实验条件下,临界半混和临界全混气量随着真空度的增大而减小; 2/3R双孔底吹位置的临界气量大于2/3R+中心孔底吹位置的;并基于导出的真空度与底吹气量拟合公式,外推出真空度为67 Pa时实际生产过程中的临界气量; VD过程钢包流场特性主要受底吹位置影响,并进一步影响混卷行为,在稳定性流场中当钢渣混合达到同一状态时,搅拌功率几乎是定值.
The mixing behavior of molten steel and slag has an important impact on refining effect in vacuum degassing(VD)process. In the VD refining process,the vacuum condition makes the bottom argon gas agitate the molten steel vigorously,and increase the exposed molten steel area,which not only aggravates the degree of steel slag mixing in the ladle,but also promotes the degassing reaction in molten steel. Moreover,it has an important influence on the desulfurization effect of molten steel. In the actual melting process,the exposed situation of the molten steel can be observed over the slag,but the steel and slag mixing situation in the ladle cannot be observed. Therefore,it has a great practical significance to study the slag mixing behavior in VD refining process under the different process conditions. In the water model experiment,the critical condition of half-mixing and complete-mixing was first defined.And then the impacts of the total blowing flow rate,vacuum degree,and the bottom blowing positions on half-mixing and complete-mixing were discussed. Besides,the effects of critical stirring energy density and stability of flow field on mixing behavior were also analyzed. The results indicate that half-mixing and complete-mixing critical gas flow rate decreases with the increase of vacuum degree in the laboratory condition. And the critical gas flow rate in 2/3 R + 2/3 R is greater than that in 2/3 R + center hole. In addition,the fitting formulas of vacuum degree and critical gas flow rate were given. Based on fitting formulas,critical gas flow rate in actual VD process was obtained when vacuum degree was 67 Pa. According to the results,the critical stirring energy density is nearly a constant when the steel-slag mixing reaches the same condition in steady flow field,which indicates that flow character can further influence mixing effect and it is affected by the bottom blowing positions.
The mixing behavior of molten steel and slag has an important impact on refining effect in vacuum degassing(VD)process. In the VD refining process,the vacuum condition makes the bottom argon gas agitate the molten steel vigorously,and increase the exposed molten steel area,which not only aggravates the degree of steel slag mixing in the ladle,but also promotes the degassing reaction in molten steel. Moreover,it has an important influence on the desulfurization effect of molten steel. In the actual melting process,the exposed situation of the molten steel can be observed over the slag,but the steel and slag mixing situation in the ladle cannot be observed. Therefore,it has a great practical significance to study the slag mixing behavior in VD refining process under the different process conditions. In the water model experiment,the critical condition of half-mixing and complete-mixing was first defined.And then the impacts of the total blowing flow rate,vacuum degree,and the bottom blowing positions on half-mixing and complete-mixing were discussed. Besides,the effects of critical stirring energy density and stability of flow field on mixing behavior were also analyzed. The results indicate that half-mixing and complete-mixing critical gas flow rate decreases with the increase of vacuum degree in the laboratory condition. And the critical gas flow rate in 2/3 R + 2/3 R is greater than that in 2/3 R + center hole. In addition,the fitting formulas of vacuum degree and critical gas flow rate were given. Based on fitting formulas,critical gas flow rate in actual VD process was obtained when vacuum degree was 67 Pa. According to the results,the critical stirring energy density is nearly a constant when the steel-slag mixing reaches the same condition in steady flow field,which indicates that flow character can further influence mixing effect and it is affected by the bottom blowing positions.
引文
[1] Yu M Q. Practice of denitrification process in 100 t vacuum ladle furnace. Res Iron Steel,2001,29(1):7(虞明全. 100 t真空精炼炉脱氮工艺的实践.钢铁研究,2001,29(1):7)
[2] Wei J L,Tang P,Wen G H,et al. Study on physical simulation of argon blowing for VD furnace ladle. Res Iron Steel,2010,38(5):6(韦江林,唐萍,文光华,等. VD炉钢包底吹氩的物理模拟.钢铁研究,2010,38(5):6)
[3] Chen S C,Zhu R,Li J S. Three-phase fluid numerical simulation and water modeling experiment of supersonic oxygen jet impingement on molten bath in EAF. J Iron Steel Res Int,2014,21(6):589
[4] Li Y H,Zhao L H,Bao Y P,et al. Flow characteristic of molten steel in slab casting tundishes. J Univ Sci Technol Beijing,2014,36(1):21(李怡宏,赵立华,包燕平,等.板坯中间包内钢液流动特性.北京科技大学学报,2014,36(1):21)
[5] Feng J H,Li B B,Wei G Z,et al. Effect of different bottom blowing argon methods on LF refining. J Univ Sci Technol Beijing,2009,31(s1):7(冯聚和,李博斌,魏国增,等.钢包底吹氩方式对LF精炼的影响.北京科技大学学报,2009,31(s1):7)
[6] Lu Q T,Yang R G,Wang X H,et al. Water modeling of mold powder entrapment in slab continuous casting mold. Journal of University of Science&Technology Beijing Mineral Metallurgy Material,2007,14(5):399
[7] Jakobsson A,Du S,Seetharaman S,et al. Interfacial phenomena in some slag-metal reactions. Metall Mater Trans B,2000,31(5):973
[8] Iguchi M,Jin Y,Shimizu T,et al. Model study on the entrapment of mold powder into molten steel. ISIJ Int,2000,40(7):685
[9] Iguchi M,Terauchi Y. Karman vortex probe for the detection of molten metal surface flow in low velocity range. ISIJ Int,2002,42(9):939
[10] Feldbauer S L. Slag Entrainment in the Mold of a Continuous Caster[Dissertation]. Pittsburgh:Carnegie Mellon University,1995
[11] Gao H. Study on Bottom Argon Blowing Process Optimization and Simulation of Cheng-Steel 120 t Ladle Furnace[Dissertation].Beijing:University of Science&Technology Beijing,2013(高海.承钢120 t钢包底吹氩工艺优化模拟研究[学位论文].北京:北京科技大学,2013)
[12] Song F F. Physical and Mathematical Simulation of 160 t Ladle Furnace with Bottom Argon Blowing[Dissertation]. Beijing:University of Science&Technology Beijing,2012(宋方方. 160 t钢包底吹氩工艺物理及数值模拟研究[学位论文].北京:北京科技大学,2012)
[13] Ai X G,Bao Y P,Wu H J,et al. A study on water modeling of ladle with bottom argon blowing in critical slag entrapment condition. Special Steel,2009,30(2):7(艾新港,包燕平,吴华杰,等.钢包底吹氩卷渣临界条件的水模型研究.特殊钢,2009,30(2):7)
[14] Mietz J,Schneider S,Oeters F. Emulsification and mass transfer in ladle metallurgy. Steel Res,1991,62(1):10
[15] Oeters F. Metallurgy of Steelmaking. Beijing:Metallurgical Industry Press,1997(F.奥特斯.钢冶金学.北京:冶金工业出版社,1997)
[16] Zhu M Y,Xiao Z Q. Mathematical and Physical Simulation in the Steel Refining Process. Beijing:Metallurgical Industry Press,1998(朱苗勇,萧泽强.钢的精炼过程数学物理模拟.北京:冶金工业出版社,1998)
[2] Wei J L,Tang P,Wen G H,et al. Study on physical simulation of argon blowing for VD furnace ladle. Res Iron Steel,2010,38(5):6(韦江林,唐萍,文光华,等. VD炉钢包底吹氩的物理模拟.钢铁研究,2010,38(5):6)
[3] Chen S C,Zhu R,Li J S. Three-phase fluid numerical simulation and water modeling experiment of supersonic oxygen jet impingement on molten bath in EAF. J Iron Steel Res Int,2014,21(6):589
[4] Li Y H,Zhao L H,Bao Y P,et al. Flow characteristic of molten steel in slab casting tundishes. J Univ Sci Technol Beijing,2014,36(1):21(李怡宏,赵立华,包燕平,等.板坯中间包内钢液流动特性.北京科技大学学报,2014,36(1):21)
[5] Feng J H,Li B B,Wei G Z,et al. Effect of different bottom blowing argon methods on LF refining. J Univ Sci Technol Beijing,2009,31(s1):7(冯聚和,李博斌,魏国增,等.钢包底吹氩方式对LF精炼的影响.北京科技大学学报,2009,31(s1):7)
[6] Lu Q T,Yang R G,Wang X H,et al. Water modeling of mold powder entrapment in slab continuous casting mold. Journal of University of Science&Technology Beijing Mineral Metallurgy Material,2007,14(5):399
[7] Jakobsson A,Du S,Seetharaman S,et al. Interfacial phenomena in some slag-metal reactions. Metall Mater Trans B,2000,31(5):973
[8] Iguchi M,Jin Y,Shimizu T,et al. Model study on the entrapment of mold powder into molten steel. ISIJ Int,2000,40(7):685
[9] Iguchi M,Terauchi Y. Karman vortex probe for the detection of molten metal surface flow in low velocity range. ISIJ Int,2002,42(9):939
[10] Feldbauer S L. Slag Entrainment in the Mold of a Continuous Caster[Dissertation]. Pittsburgh:Carnegie Mellon University,1995
[11] Gao H. Study on Bottom Argon Blowing Process Optimization and Simulation of Cheng-Steel 120 t Ladle Furnace[Dissertation].Beijing:University of Science&Technology Beijing,2013(高海.承钢120 t钢包底吹氩工艺优化模拟研究[学位论文].北京:北京科技大学,2013)
[12] Song F F. Physical and Mathematical Simulation of 160 t Ladle Furnace with Bottom Argon Blowing[Dissertation]. Beijing:University of Science&Technology Beijing,2012(宋方方. 160 t钢包底吹氩工艺物理及数值模拟研究[学位论文].北京:北京科技大学,2012)
[13] Ai X G,Bao Y P,Wu H J,et al. A study on water modeling of ladle with bottom argon blowing in critical slag entrapment condition. Special Steel,2009,30(2):7(艾新港,包燕平,吴华杰,等.钢包底吹氩卷渣临界条件的水模型研究.特殊钢,2009,30(2):7)
[14] Mietz J,Schneider S,Oeters F. Emulsification and mass transfer in ladle metallurgy. Steel Res,1991,62(1):10
[15] Oeters F. Metallurgy of Steelmaking. Beijing:Metallurgical Industry Press,1997(F.奥特斯.钢冶金学.北京:冶金工业出版社,1997)
[16] Zhu M Y,Xiao Z Q. Mathematical and Physical Simulation in the Steel Refining Process. Beijing:Metallurgical Industry Press,1998(朱苗勇,萧泽强.钢的精炼过程数学物理模拟.北京:冶金工业出版社,1998)