Simulation on Effect of Divergent Angle of Submerged Entry Nozzle on Flow and Temperature Fields in Round Billet Mold in Electromagnetic Swirling Continuous Casting Process简

A new process for swirling flow generation in the submerged entry nozzle （SEN） in continuous casting process of steel was proposed. A rotating electromagnetic field was set up around the SEN to induce swirling flow by Lorentz force. The flow and temperature fields in the SEN and round billet mold with electromagnetic swirling were numerically simulated and then verified by the electromagnetic swirling model experiment of low melting point alloy. The effects of divergent angle of the SEN on the flow and temperature fields in mold with electromagnetic swirling were investigated. The electromagnetic swirling flow generator （EMSFG） could effectively induce swirling flow of molten steel in the SEN, which consequently improved greatly the flow and temperature fields in the mold. Below the nozzle outlet in mold, with the increase of divergent angle, the stream of bulk flow diverged more widely, the high temperature zone shifted up, and the temperature field became more uniform. Above the nozzle outlet in mold, with 350 A electromagnetic swirling, when the divergent angle of the SEN increased, the upward flow velocity and the meniscus temperature first increased and then decreased. With a divergent angle of 60~, the upward flow velocity and meniscus temperature reaced the largest value.     

钢液浇注的钢流控制与耐火材料

介绍连铸钢液保护、整体塞棒控流、浸入式水口新材料和ＲＴＶ浇注控制系统新技术，及其对连铸生产的作用和意义。     

电磁出钢装置中填装料对固-液界面位置的影响

 在电磁出钢系统中 ,为了提高感应加热效果以实现快速出钢 ,需将固-液界面控制在感应线圈的有效加热区内。设计了模拟钢包上水口处固-液界面测量装置,考察了上水口内在高中低碳钢的出钢温度分别为1550、1600、1620℃时,铁碳合金颗粒的成分、形状、大小对固-液界面的影响规律。结果表明：使用铸铁填装料比使用铸钢填装料时固-液界面的下移量要大,并且成分的影响随着钢液温度的升高有增大的趋势;规则球形颗粒比不规则的砂形颗粒对固-液界面位置影响要大,而且固-液界面的下移量随着填装料粒径的增大而增大;选用粒径为2.0mm的铸铁颗粒作为填充料,当出钢温度为1600和1620℃时,固-液界面位置能够进入有效加热区;当出钢温度为1550℃时,使用粒径为4.0mm的铸铁颗粒做填充料时,固-液界面位置也能够进入有效加热区。     

Numerical Prediction on the Flow Field of Molten Steel and the Trajectory of Inclusion in Continuous Casting Mold Effected by Electromagnetic Field

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防止船板(铝镇静)钢水口结瘤的生产实践

分析了船板（铝镇静）钢浇注时水口堵塞的成困，借鉴国内外研究成果和冶炼实践，结合酒钢船板钢生产实际，提出防止水口结瘤堵塞的措施，解决了铝镇静钢浇注时水口结瘤堵塞问题。     

Optimum Position of Electromagnetic Brake on Slab Caster

SymbolList　　B———Magneticfluxdensity ,T ;　　CD———Dragcoefficient;　　d———Diameter ,m ;　　g———Gravitationalacceleration ,m·s-2 ;　　h———Timestep ,s ;　　J———Currentdensity ,A·m-2 ;　　la,lb———Sizeofslabcross section ,m ;　　ln———Immersiondepthofnozzle ,m ;　　p———Pressure ,Pa ;　　t———Time ,s ;　　u→ ———Velocity ,m·s-1;　　vc———Castingspeed ,m·min-1;　　X→ ———Displacement ,m ;　　———Electricpotential,V ;　　ρ———Density ,kg·m-3;…     

钢包水口偏心率对浇注过程影响的数学模拟

 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。     

冷轧无取向电工钢连铸生产实践

通过对连铸过程生产实践的总结以及现场数据分析,研究了太钢在生产冷轧无取向电工钢时连铸过程中间包钢水增碳、二次氧化、钢水吸氮以及在冷轧过程中钢板表面重皮、夹杂缺陷等的原因以及解决措施。结果表明,通过采用专用冷轧无取向电工钢中间包覆盖剂和结晶器保护渣、加强钢水从大包至中间包保护浇注、稳定连铸过程拉速和液面自动检测控制等措施解决上述存在的问题。     

Effect of Nozzle Type and Swirl on Flow Pattern for Initial Filling Conditions in the Mould for Up‐hill Teeming

With increasingly more stringent requirements on steel quality and productivity in uphill teeming production, it is vital to attain more desirable fluid flow conditions in the filling of the mould. In this investigation, physical and mathematical modelling was carried out to study the effects of nozzle type and utilization of a swirl generator in the inlet nozzle on the flow pattern in the ingot mould during the initial filling period. Specific focus was on the effects on the resultant hump and axial velocities. Three cases were considered: 1) a straight nozzle, 2) a divergent nozzle, and 3) a divergent nozzle combined with a swirl generator. It was found that usage of the divergent nozzle, compared to the straight nozzle, resulted in a smaller hump and lower axial velocities in the bath. For the combination of divergent nozzle and swirl generator, these findings were even more pronounced, with the hump practically eliminated, and the axial velocities, as well as the turbulence at the meniscus, significantly lower. The findings of the study suggest that a divergent nozzle combined with a swirling flow generated in the nozzle could be used in the up‐hill teeming process in purpose to get calmer initial filling conditions.     

60钢小方坯缺陷对成品盘条性能的影响研究

对60钢试件进行低倍酸浸试样试验;根据试验结果,分析了60钢小方坯的中心疏松、中心偏析、缩孔、非金属夹杂等缺陷对轧制成材后的60钢盘条性能影响的原因。研究表明:60钢小方坯的中心疏松、中心偏析、缩孔、非金属夹杂物等缺陷降低了成品材的力学性能,是造成盘条线材冷拔断裂的主要原因;浇注过程中适当降低钢水过热度,采用电磁搅拌,加强结晶器液面控制,稳定钢水在浇注过程中的温度,可以减少小方坯缺陷的产生。     

电磁软接触结晶器内钢液面高度对磁场分布的影响

利用有限元软件ANSYS对软接触电磁连铸结晶器内磁场进行三维数值模拟,分析了结晶器内钢液面高度对磁场及电磁力分布的影响.结果表明:钢液使得磁感应强度集中在钢液的侧表面;当钢液面低于线圈上沿时,钢液中磁感应强度的最大值出现在钢液上表面附近,并沿拉坯方向逐渐递减;当钢液面高于线圈上沿时,随着钢液面的升高磁感应强度的最大值向线圈中部移动;钢液侧表面所受电磁力的分布趋势与磁感应强度的分布趋势基本一致.     

Uphill Teeming Utilizing TurboSwirl to Control Flow Pattern in Mold

The flow pattern has widely been recognized to have an impact on the exogenous non‐metallic inclusion generation in the gating system and mold flux entrapment in the mold in the uphill teeming process. The possible solutions of the flow pattern control are required to be reliable and practical in order to improve the yield and the ingot quality in the steel production. In this work, a mathematical model of a new novel swirling flow generation component, TurboSwirl, was studied to investigate the flow pattern of steel in the gating system and molds based on the authors' previous study. The same calculation method and boundary conditions were adopted. The results show that a much calmer initial filling condition with less fluctuations is achieved in the mold with a swirling flow by using the TurboSwirl compared to previous studies. In addition, the initial position of the mold powder bags can further be lowered in the mold due to a decreased hump height. Moreover, the difference between the hump height and the surface height in the present model has a maximum value of 83 mm, which gives a lower risk of mold flux entrapment. Furthermore, the maximum wall shear stress value can generally be lowered with less fluctuations after the first hump formation in the mold at 2.5 s from the teeming start. In conclusion, the initial filling conditions can be substantially improved by the use of TurboSwirl flow pattern control.     

生产轴承钢用浸入式水口的堵塞机理

 由于生产轴承钢水口的堵塞,严重影响生产的顺利进行。利用化学分析、相分析和岩相分析的方法对浸入式水口堵塞物及其耐火材料进行研究。结果表明,发生水口堵塞的位置主要在水口渣线部,堵塞物化学成分主要以金属Fe为主,其它含有Al、Cr、Si、C等物质。而水口内壁物质主要是Al2O3、SiO2、CaO、Cr2O3、FeO等氧化物。从X射线分析看,这些物质主要是熔点较高的CaO和Al2O3形成的CaO·2Al2O3和CaO·6Al2O3。由此分析得出,钢水金属冷凝、连铸保护浇铸不好和钢水不洁净是造成水口堵塞的主要原因。同时给出了防止水口堵塞的技术措施。     

钢包水口絮流分析

通过对钢包浇钢时水口絮流物的残样进行分析,查清了水口絮流物的主要成分是铁和六铝酸钙。研究分析了六铝酸钙的来源,主要是钢包在使用过程中钢包渣与包衬耐火材料发生反应的产物,这些反应产物粘结在钢包内衬。随着冶炼周期的增加,钢包内的六铝酸钙积累到一定程度后脱落到钢水中引起钢包水口絮流。提出了强化反吹倒渣制度可减少钢包水口絮流。     

钢包引流砂烧结与钢包自动开浇率提升研究进展

为了提升钢包自动开浇率,总结了钢包引流砂烧结的研究与工业实践成果,阐述了引流砂的烧结性能、钢包自动开浇的影响因素及提升措施,重点关注了不同材质引流砂的烧结机理和钢液对引流砂烧结的作用机制.不同材质引流砂的烧结结构类似,一般分为烧结层(包括部分烧结层)和未烧结层.引流砂的实际烧结层很薄,而且绝大多数引流砂会呈现未烧结的状...     

浇注钢包环出钢口四孔透气塞吹氩控制下渣工艺北大核心CSCD

针对浇注钢包环出钢口四孔透气塞吹氩控制下渣工艺,建立了某钢厂130 t钢包三维DPM-VOF耦合数学模型以计算浇注钢包下渣过程,并通过冷态实验验证了该模型的有效性。利用该模型研究了不同偏心率对下渣行为的影响,揭示了该工艺控制下渣的行为规律,并分析了吹氩流量对控制下渣的影响。结果表明,随着偏心率的增大,不同浇注高度下的最大切向速度减小,汇流漩涡临界高度降低。环出钢口四孔透气塞吹入氩气后,气泡流股的汇聚有效地减弱了水口上方钢液的周向旋转速度,大幅降低了汇流漩涡下渣临界高度。4个气泡流股的气液两相流会抑制流向水口钢液的径向流动速度,由排流沉坑引起的下渣也得到明显抑制。随着吹氩流量的增加,下渣临界高度呈降低趋势。就本研究而言,控制下渣的最佳吹氩流量为30 L/min。     

耐火浇注料在轧钢加热炉上的应用

轧钢炉窑用耐火浇注料的使用寿命与材质，组合配比，炉体设计，施工，烘炉诸因素有关，在进行炉体设计时，应视现场使用条件正确选用浇注粒料；炉顶采用柔性吊持及合理的扼注注下要用，采用格式浇注工艺，可收到节能，降低工程旨用与延长炉顶寿命的效果。     

电磁搅拌作用下水口深度对液面波动的影响

 结晶器内液面波动会影响连铸坯的质量,施加电磁搅拌使钢液的液面呈旋转抛物面。电磁搅拌电流过大或拉速过高会造成保护渣卷渣现象,对铸坯质量造成不利的影响。以某钢厂[?]250 mm连铸圆坯结晶器电磁搅拌为研究对象,采用电磁-流体单相耦合的方式及流体体积函数VOF模型,建立描述结晶器电磁搅拌作用下液面波动的数学模型,研究电磁搅拌作用下浸入式水口深度对液面波动的影响。研究表明,通过增大水口深度,能够改善因电磁搅拌强度过大或拉速过大造成的卷渣现象,减小水口附近的液面波动。     

Influence Factors of SEN Clogging of Rare-Earth Steel Continuous Casting and Solve Ideas of Japanese Steel Enterprises

The clogging behavior of submerged entry nozzle (SEN) is the main reason restricting the continuous casting of steel, which seriously affects the application and popularization of rare-earth (RE) steel. Through literature analysis, herein, the main influencing factors and mechanism of RE steel continuous casting immersion outlet clogging, and sorts out the main ideas and practices of relevant Japanese enterprises in solving SEN clogging in recent years, are summarized, mainly including the following: 1) optimizing SEN materials to reduce nozzle clogging reactions; 2) using Ar-blowing SEN; 3) applying electromagnetic field to eliminate charge and inhibiting clogging reaction; and 4) and regulating the composition of molten steel to reduce the possibility of clogging, etc. The combination of these advantages and measures is a feasible way to solve the nozzle clogging of RE steel continuous casting nozzle.     

链轮电磁感应加热过程中的优化设计

 电磁感应加热技术有效地节约了钢铁制造成本,积极推动了钢铁行业绿色制造。优化重载链轮电磁感应加热过程是生产高品质链轮的一个重要分支。在对链轮进行热处理强化时,普通圆形感应线圈在单一电流频率下难以实现齿廓的均匀加热,容易导致淬火层的硬度分布不均,造成工件开裂。仿形感应线圈比普通圆形感应线圈具有更好的加热效果,但是仿形感应线圈研发周期长,成本昂贵,不利于大规模推广应用。考虑到实际加工成本及生产需求,在完全仿形感应线圈的基础上,提出了一种齿顶位置为V形角的仿齿廓感应线圈,该感应线圈到齿顶和齿根的间隙不等。进一步建立了双排链轮电-磁-热耦合温度场模型,并进行试验验证。研究发现这种带V形角的感应线圈与圆形感应线圈相比,能够改善磁通量在空间的分布方式,强化感应线圈和齿根之间的临近效应,同时减弱感应线圈和齿顶间的临近效应,提高了链轮沿齿廓温度的均匀性。量化分析了不同电磁参数(电流频率和电流密度)和感应线圈的结构(V形角,感应线圈到齿轮的距离)对提升加热速率和改善温度均匀性的作用规律。感应线圈的V形角结构有利于提高齿轮的电磁加热质量,对推动实际加工应用和提升企业效益具有重要生产价值,有利于促进精品钢生产。