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钢包浇铸末期旋涡卷渣严重影响钢水洁净度和金属收得率。利用钢包渣示踪法研究了上海梅山钢铁股份有限公司250 t钢包浇铸过程卷渣行为。通过在中间包注流区采集钢样,基于含Ba夹杂物成分、尺寸和形貌研究卷渣形成的夹杂物特性,并通过夹杂物中平均Ba含量变化来判断旋涡卷渣发生的程度。结果表明:卷渣形成的夹杂物普遍尺寸较大、形貌呈球形,在钢包余钢量不低于15~18 t的时候便开始出现旋涡卷渣。为了抑制旋涡卷渣,针对梅钢250 t钢包的实际工况,提出了一种新的出水口结构,并利用物理模拟试验对比了常规出水口和新出水口的旋涡特性,采用新的出水口可以显著降低钢包的起旋高度和贯通高度。 相似文献
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钢包浇铸过程中,如果产生漩涡可能将渣卷入钢液中,从而给生产带来不利的影响。通过物理模拟的方法研究某钢厂钢包浇铸末期出现漩涡的现象,通过加入不同的阻漩装置,研究钢液起漩高度和贯穿高度变化。试验发现,起漩和贯穿高度随着钢包静置时间延长而减小,静置时间30 min时比静置5 min时起漩和贯穿高度分别下降37.88%和45.64%;阻漩装置的位置和尺寸均会对钢包漩涡高度产生不同的影响,阻漩装置位置或尺寸不合适,可能会使漩涡现象提前出现,恶化浇铸条件;在钢包侧壁上放置阻漩装置,漩涡出现高度可降低46.69 %以上。钢包底部阻漩装置距离水口位置增大时,阻漩效果增加。 相似文献
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本文通过对酒钢CSP钢包过程控制研究表明:静置钢包内壁温降1℃/min,外壁温降0.4℃/min;钢包内外壁的温差为:包底>包壁>渣线;随钢包的综合包龄、一次性包龄的增加,钢水的温降越大;缩短钢包的循环周期,减少周转钢包的数量,利于钢包的循环、管理。 相似文献
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湖南衡阳钢管厂AC(交流)EAF-LF(钢包炉)-HCC(水平连铸)电炉短流程炼钢系统自1995年5月热试出钢以来,已生产碳素结构钢、合金结构钢等各种钢15万t,并试炼成功液压支柱管钢等钢种。作为该流程的中间调控精炼处理装置-LF,由于具有加热、吹氢、还原气氛下可控炉渣精炼等功能,在提高生产率、降低钢中气体及夹杂含量、准确控制并均匀钢水化学成分及温度等方面起到了重要作用。下面将该工艺研究及生产实践情况进行介绍。1设备及工艺1.1设备主要技术参数(AC)EAF-LF-HCC电炉短流程炼钢系统采用40t钢包炉,其主要技术参数如… 相似文献
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RH真空室熔池和钢包内钢液整体流场的数学模拟 总被引:2,自引:0,他引:2
应用N-S方程、k-ε双方程模型及两相区结构模型对RH真空室熔池和钢包内钢液流场进行数值计算,为进一步计算浓度场和温度场奠定了基础,并解释了一些工艺现象。另外还用该模型计算了RH内钢液的循环流量,给出了最佳氩气喷吹量。 相似文献
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Mathematical simulation of fluid dynamics during steel draining operations from a ladle 总被引:2,自引:0,他引:2
O. Davila L. Garcia-Demedices R. D. Morales 《Metallurgical and Materials Transactions B》2006,37(1):71-87
Fluid flow dynamics during ladle drainage operations of steel under isothermal and nonisothermal conditions has been studied
using the turbulence shear stress transport k-ε model (SST k-ω) and the multiphase volume of fluid (VOF) model. At high bath levels, the angular velocity of the melt, close to the ladle
nozzle, is small rotating anticlockwise and intense vertical-recirculating flows are developed in most of the liquid volume
due to descending steel streams along the ladle vertical wall. These streams ascend further downstream driven by buoyancy
forces. At low bath levels, the melt, which is close to the nozzle, rotates clockwise with higher velocities whose magnitudes
are higher for shorter ladle standstill times. These velocities are responsible for the formation and development of a vortex
on the bath free surface, which entrains slag into the nozzle by shear-stress mechanisms at the metal-slag interface. The
critical bath level or bath height for this phenomenon is 0.35 m (in this particular ladle design) for a ladle standstill
time of 15 minutes and decreases with longer ladle standstill times. At these steps, the vertical-recirculating flows are
substituted by complex horizontal-rotating flows in most of the liquid volume. Under isothermal conditions, the critical bath
level for vortex formation on the melt free surface is 0.20 m, which agrees very well with that determined with a 1/3 scale
water model of 0.073 m. It is concluded that buoyancy forces, originated by thermal gradients, as the ladle cools, are responsible
for increasing the critical bath level for vortex formation. Understanding vortex mechanisms will be useful to design simple
and efficient devices to break down the vortex flow during steel draining even at very low metal residues in the ladle. 相似文献
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钢包的水口偏心率会显著影响浇注末期汇流旋涡的形成和发展过程。基于钢包特征设置合理的水口偏心率,有利于控制旋涡形态、抑制旋涡的危害。但是偏心率的变化如何改变流场,对浇注过程产生哪些影响,目前的研究并不充分。通过数值模拟方法,研究了水口偏心率对钢包流场和旋涡的影响规律,同时定义了“影响度”指标,定量分析了偏心率对浇注过程中表征流场和旋涡特性的14个物理量(如水口流量、旋涡角速度、湍动能、水口含气率等)的影响程度。结果表明,水口偏心率和各物理量之间存在非线性关系;不同物理量变化的临界点不同,普遍为0.5~0.7,旋涡的稳定性和容器壁面是影响临界点的主要因素。 相似文献
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30tVOD ladle smelting stainless steel was used as the process background, and the numerical and physical simulations were applied to investigate the flow and mixing characteristics of molten steel during the 30tVOD refining process. The cold experiment was employed to investigate the mixing behaviors of molten steel under the bottom and combined blowing systems. The flow features of molten steel were analyzed by numerical simulation with different blowing conditions. The results show that when the plug position of the ladle is located on 1/4R(R is the radius of ladle bottom), whether top- bottom blowing or bottom blowing, the molten steel is mixed well, and mixing time compared to the central position is reduced by 46% and 14% respectively. In addition, the comparison of flow field and turbulent kinetic energy of the molten steel show that when the bottom blowing position is 1/4R, the flow direction of the molten steel caused by the top blowing and the bottom blowing is better near the bath surface, and active volume ratio of molten steel is higher than that of other blowing positions. Current results were validated in industrial VOD furnace, which indicates that 1/4R is regarded as the optimum injection position for combined stirring. 相似文献
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采用ASPEX扫描电镜中的自动特征分析功能研究了交换钢包过程(取样浇次第4、5炉)对IF钢连铸板坯表层的洁净度的影响,且对比研究了交换钢包过程浇铸铸坯(交接坯)与正常浇铸铸坯(正常坯)的表层洁净度.结果表明:正常坯与交接坯中尺寸大于20μm的表层夹杂物可分为三类:(1)簇群状Al2O3(包括气泡+簇群状Al2O3);(2)簇群状TiOx-Al2O3夹杂物;(3)保护渣夹杂物.正常坯表层的大型夹杂物主要为簇群状Al2O3,没有检测到保护渣夹杂物.换包开浇后铸坯总氧质量分数从14×10-6增至17×10-6,交接坯表层检测到较多的第2夹杂物,说明钢包开浇后钢水被轻微氧化.此外,钢包开浇后剧烈的液面波动也导致了保护渣的卷入.在当前工艺下,换包对IF钢铸坯表层洁净度的影响长度约为11m. 相似文献
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以250t底吹氩钢包为原形,根据相似原理进行水模型实验,研究了不同透气砖布置参数、吹氩量、加料位置及透气砖透气性能变化对精炼效果的影响.结果表明:0.75R(透气砖在距钢包底部中心为0.75倍钢包底部半径R的位置)的双透气砖布置较0.64R、0.5R混匀时间短,但对包壁的冲刷严重;双透气砖大夹角(135°、180°)布置比小夹角(45°、90°)混匀时间短,0.64R-180°的双透气砖对称布置方案最优.在透气砖上方或双透气砖连线中垂线区域内添加物料,混匀时间最短;吹气量控制在67~70m3/h之间,可充分利用气体的搅拌能量,满足混匀时间短且不会产生卷渣的洁净钢精炼要求;透气砖堵塞较双孔正常吹气混匀时间延长,顶部钢液形成两个大小不一的裸露亮圈,并加重对包壁耐材的冲刷与侵蚀,降低钢液的混均效果及钢的洁净度. 相似文献