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为揭示各种行波磁场铸流搅拌的电磁冶金效果,基于计算域分段法建立了断面1280 mm×200 mm板坯连铸电磁、流动、传热和凝固的耦合模型,利用电气参数和磁感应强度的实测值和预测值的对比验证了模型的可靠性。研究表明:行波磁场搅拌器因电磁推力的方向性特点在板坯二冷区搅拌过程中均表现有不同程度与特征的端部效应,辊后箱式搅拌器(Box-typed electromagnetic stirrer, B-EMS)的单侧安装形式导致板坯内弧侧磁感应强度远大于外弧侧,辊式搅拌器(Roller-typed electromagnetic stirrer, R-EMS)的对辊安装形式则使磁感应强度呈现对称分布。在400 kW和7 Hz的相同电气参数下,R-EMS的电流强度比B-EMS高75 A;尽管箱式电磁搅拌的有效作用区域较辊式电磁搅拌大,铸坯中心钢液过热耗散区域大,但辊式搅拌推动钢液冲刷凝固前沿形核作用则明显大于箱式搅拌。两者均具有较好的抑制柱状晶生长、促进凝固前沿等轴晶形核与发展的能力,将不锈钢板坯等轴晶率提高至45%的门槛值以上,其中间隔型反向辊式搅拌器下的等轴晶率比箱式搅拌高约17%。综合表明,基于行波磁场铸流搅拌的间隔型反向辊式搅拌器有望更好地消除铁素体不锈钢板材表面皱折缺陷。 相似文献
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利用有限元分析软件,建立了380 mm×280 mm大方坯结晶器电磁搅拌的三维数学模型,系统研究了电磁搅拌工艺参数(电流250~500 A,频率1.5~3.0 Hz,结晶器铜板厚度34~40 mm)对结晶器内电磁场的分布影响。结果表明,结晶器内磁感应强度沿铸流轴向呈"两端小、中间大"分布;电流从350 A增大到500 A,搅拌器中心的磁感应强度呈线性递增;频率由1.5Hz增大到3.0Hz,搅拌器中心磁感应强度仅减小0.001 5 T;随着结晶器铜板厚度的增大,铸坯宽面、窄面和角部的磁感应强度都减小。在实际连铸U71Mn重轨钢中,电流应该维持在400 A以上。 相似文献
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本文基于某铝厂300 kA铝电解槽基本结构及尺寸,运用大型有限元软件ANSYS建立铝电解槽电、磁、流场模型,对该铝厂铝电解槽进行数值仿真计算。电解质层中电流主要为垂直分布,铝液层电流出现较大的水平方向分量值;磁场x方向沿短轴为反对称分布,y方向沿长轴大体上呈现反对称分布,z方向大体上沿长轴呈反对称分布;铝液-电解质界面最大隆起高度为3.28 cm。探究了铝电解槽电磁流场分布情况,为铝电解槽节能降耗生产提供理论指导。 相似文献
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聚磁参数对直流电磁泵磁场分布影响的数值模拟 总被引:1,自引:0,他引:1
直流电磁泵是镁合金铸造过程的重要设备,而电磁铁聚头长度和截面积是影响电磁泵效率的关键参数.作者采用ANSYS软件研究了聚磁头结构对电磁泵聚磁头间隙磁场分布的影响.模拟结果表明,由于聚磁效应,聚磁头结构能有效提高聚磁头间隙处磁感应强度,且随聚磁头长度的增加,磁感应强度分布均匀性有所提高;随着聚磁头截面特征长度的增大,聚磁头间隙处磁感应强度先增大后减小,聚磁头截面特征长度为20~30 mm时聚磁效果最佳.研究结果对于深入认识直流电磁泵的磁场特性并对其优化具有理论价值和现实意义. 相似文献
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ABSTRACTIn this paper, an electromagnetic torque device based on the theoretical model was established to determine the optimum frequency accurately and conveniently in billet and bloom continuous casting with in-mould electromagnetic stirring (M-EMS). Magnetic characteristics with M-EMS was investigated by numerical simulation and physical experiment with the application of electromagnetic torque device and gauss meter. In addition, the effects of stirring frequency with M-EMS on macro segregation and equiaxed crystal ratio were compared and analysed for 55SiCr with 150?mm?×?150?mm billet caster and BU with 310?×?360?mm bloom caster by a series of plant trials, respectively. The results showed that maximum magnetic flux density and maximum electromagnetic torque occurred with different frequency and same current in M-EMS, and central equiaxed crystal ratio and macro segregation has been significantly improved by optimum frequency with M-EMS. 相似文献
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TheLMF (LevelMagneticField)technologybasedonstaticmagneticfieldcanbeusedtoimprovecontinuouscasting ,suchasforreducingimpactonnarrowsidesofshell ,eliminatinglargenonmetallicinclusions ,preventingmoldfluxentrappingandim provingslabcleanliness ,etc[1,2 ] .Theeffectofstaticmagneticfieldonsolutebehaviorandcrystallizationduringsolidificationwasinvestigated[3 ] .Theknowl edgeanddesignofmagneticfieldisveryimportantbaseofLMFtechnology .However ,themagneticfieldwasgenerallytakenasaone dimensionalfie… 相似文献
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在马钢工业生产条件下,用高斯计空载测量Φ380 mm圆坯连铸结晶器内在电流参数400~510A、2.0~2.5 Hz的范围内磁感应强度的分布特性。结果表明,结晶器中心垂直方向磁感应强度变化曲线呈波峰状,在离结晶器上口约530 mm的电磁搅拌器中心处有最大值;在结晶器水平截面上磁感应强度沿截面中心至边缘逐渐增大。钢液弯月面处的磁感应强度是结晶器中心最大值的10%左右。马钢在现有生产条件下采用400 A/2.5 Hz的电流参数,相应电磁搅拌强度明显偏低。 相似文献
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Hong Lei Jimin Jiang Bin Yang Yan Zhao Hongwei Zhang Weixian Wang Guiwen Dong 《Metallurgical and Materials Transactions B》2018,49(2):666-676
Mathematical simulation is an effective tool to analyze the fluid flow and the inclusion behavior in the bloom continuous caster with mold electromagnetic stirring (M-EMS). The mathematical model is applied to the modeling of magnetic field, flow field, and inclusion field. Due to the introduction of Archimedes force, the collision mechanism and inclusion’s slipping velocity should be modified in the inclusion mass and population conservation model. Numerically predicted magnetic field, flow field, and the inclusion spatial distribution conform to the experimental results in the existing literature. Lorentz force plays an important role in the fluid flow, and Archimedes force plays an important role in the inclusion distribution in the continuous caster. Due to Brownian collision, Stokes collision, Archimedes collision, and turbulent collision, the coalescence among inclusions occurs in the bloom continuous caster with M-EMS. Among the four types of collisions, turbulent collision occurs most frequently, followed by Archimedes collision and Stokes collision. The frequency of Brownian collision is several orders of magnitudes smaller and is therefore negligible. The inclusion volume concentration, number density, and characteristic radius exhibit a U-shape in the continuous caster without M-EMS. However, with M-EMS, they exhibit an inverted U-shape. 相似文献
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《Canadian Metallurgical Quarterly》1999,38(5):301-309
Increased casting productivity, especially with the introduction of high speed billet casting (HSBC), re-emphasized the importance of high performing mold electromagnetic stirring (M-EMS) in attaining the targets of productivity and product quality. To provide operating flexibility and to enhance metallurgical performance, adapting M-EMS design to the requirements of casting practice with either the open stream pouring or submerged entry nozzle (SEN) has become critical. In that context, it is especially important to assess the effects of EMS design parameters that control stirring velocity in the meniscus region and the rest of the mold. Such a control is the key to EMS compatibility with the continuous casting practice and its high metallurgical performance.In this paper, we discuss different M-EMS designs with reference to their metallurgical performance. 相似文献
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钢管缺陷漏磁场及影响漏磁信号因素的分析 总被引:6,自引:0,他引:6
介绍了钢管检测中常见的缺陷漏磁场模型和漏磁场分布,以及对凹坑缺陷漏磁场进行的模拟研究。比较了两种缺陷漏磁检测信号的时频特性,讨论了缺陷深度、励磁电流、检测探头纵向旋转速度等对矩形槽缺陷漏磁感应电压信号的影响。研究发现,缺陷深度和漏磁感应信号峰值约呈线性关系,这可作为钢管缺陷检测的应用基础。 相似文献
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20CrMnTi钢(%:0.17~0.23C、0.80~1.10Mn、1.00~1.30Cr、0.04~0.10Ti)300 mm×340 mm铸坯结晶器-末端电磁搅拌(M-EMS,F-EMS)和3段复合电磁搅拌(M-EMS,S-EMS,F-EMS)对铸坯碳偏析影响的试验结果表明,当M-EMS和F-EMS电流分别从2 HZ/250 A和20 HZ/150 A降至2 HZ/100 A和20 HZ/100 A时,铸坯断面碳成分的极差由0.05%降至0.02%;当采用M-EMS为2 HZ/100 A,S-EMS为20 HZ/50 A,F-EMS为20 HZ/100A三段复合电磁搅拌时,铸坯断面碳成分的极差为0.02%,轧材中心疏松由原2段电磁搅拌的1.0~2.0级降至1.0~1.5级,方框形偏析2.0级出现率由9.7%降至0.8%。 相似文献
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Man Yao Da-Cheng Fang He-Bi Yin Jin-Cheng Wang Xiao Liu Yan Yu Jun-Jiang Liu 《Metallurgical and Materials Transactions B》2005,36(4):475-478
This article focuses on the influence of mold-electromagnetic stirring (M-EMS) on mold heat transfer, for the purpose of developing
a general approach to study mold heat-transfer characteristics in continuous casting of small round billets. This study was
based on an experimental system with simultaneous, on-line monitoring of mold heat flux and temperature. Several phenomena
are discussed including the local mold heat flux/temperatures and their responses to the variation of M-EMS current. 相似文献