Calculation of Solidification Process of Continuous Cast Bar

In this paper,it presents the results of calculation of solidification process of copper continuous cast bar by cross section size 120 mm × 70 mm with application of Pro Cast 2010 software. The estimation of mould design effect on solidification process of continuos copper cast bar is completed at various speeds of casting.Profiles of liquid metal cavities and temperature allocations in the cast bar at various casting speeds are defined.The analysis of received liquid metal cavity profiles shows that a new mold construction allows significantly decrease of the length of the liquid metal cavity during continuous copper casting at HAZELETTcasting machine and the increase of maximum casting speed from 10 to 11 m / min. Adequacy of the results of copper continuous cast bar solidification process calculation is confirmed by the experimental data.

一种铜液连续测控温度技术

介绍了开发铜液连续测控温的一种技术。铜/钢行业金属液测温难度大,多为人工用快速热偶间歇抽测的粗略方式;现开发了一种热偶护套管涂层制造技术,该热偶经实测铜液试验,达到了连续使用及耐热震基本要求;通过感应熔铸炉自动控温技术改造,铜液熔炼期及浇注期的过热度实现精确调控,提升了熔铸工艺温度控制技术水平和产品质量;该技术在铜液/钢液等金属液测控温技术领域,具有较广泛的推广应用价值。

轧辊制造技术与发展趋势

介绍了生产轧辊的四种常规方法以及随着轧制技术的发展而陆续发展起来几种生产轧辊的新方法,分析了每种方法的优缺点,并介绍了国内轧辊制造业现状及国际轧辊制造技术的发展趋势,对现实生产具有一定指导意义。

电磁搅拌对液态金属运动及凝固组织的影响

旋转型电磁搅拌在钢的连续铸造、铸件成形与凝固、半固态浆料制备、液态金属电磁净化等工艺过程中的应用受到了材料工作者的高度重视,并不断地取得了电磁搅拌应用技术开发与理论研究的成果。分析了旋转型电磁搅拌作用下液态金属运动特点及电磁力计算,建立了液态金属旋转运动的数学模型,并得到周向速度分布的表达式,研究了旋转型电磁搅拌对连铸坯凝固组织的影响,为在旋转型电磁搅拌应用中工艺参数的优化提供了依据。

电渣冶金技术的最新发展趋势

简要回顾了电渣重熔工业生产50年的发展历史,重点对近年来电渣冶金新技术进行了介绍和评价,包括快速电渣重熔,双极串联电渣连铸技术,特厚板坯电渣重熔,大型电渣重熔钢锭凝固偏析控制,可控气氛电渣炉和电渣液态浇铸技术。在新的发展阶段,电渣冶金技术向高效、节能、环保和满足更高质量方向发展。

电渣液态浇注空心钢锭的数值模拟

建立了电渣液态浇注空心钢锭体系三维准稳态数学模型,利用商业软件ANSYS与CFX进行顺序耦合求解,得到了电渣液态浇注空心钢锭过程的电场、磁场、温度场与流场.计算结果表明,由于采用了导电结晶器技术,渣池电位、焦耳热分布、磁场分布、流场分布与温度场分布等均有别于传统电渣重熔过程.渣池高温区位于外结晶器壁附近,远离渣金界面,最高温度为2 113 K.渣池流场存在两个漩涡,浮力为主要的驱动力,熔渣最大速度为0.068m.s-1.金属熔池呈浅平状,有利于提高空心钢锭的凝固质量.

连铸式液态电渣浇注圆锭表面质量的影响因素

用连铸式液态电渣浇注技术生产45#号钢,探讨了直径为1 000 mm圆形铸锭表面质量的影响因素.实验结果表明:合适的钢水浇注温度(1 606℃);较高电压(80 V)和稳定的电流(18 kA);使用专用预熔渣;均匀稳定、适量的二次冷却控制;始终稳定的抽锭速度(8~10 mm/min)都是钢锭获得良好的表面质量比较重要的影响因素.

磁感应强度对高速连铸流动控制结晶器内金属液流动的影响

流动控制结晶器(FC-Mold)是高速连铸的重要设备,模拟了流动控制结晶器内金属液的流动情况,研究磁感应强度对结晶器内金属液流动的影响。实验结果表明:静磁场不仅具有制动钢液流的作用,还具有阻碍金属液运动,改变流动方向的作用。高速连铸采用FC-Mold,能够改善结晶器内金属液流动;磁感应强度增大,自由液面的流动得到改善,液面波动受到抑制,下环流的冲击强度减小。

金属材料近终成形技术

近终成形技术是金属材料成形的新技术．目前已使用的近终成形技术有近终形连铸、粉末冶金、喷射沉积成形、电渣转注、电磁铸造、金属泥成形等．

第二代电渣冶金技术与重大装备制造

2010年是我国电渣重熔技术工业化50周年.论述了电渣冶金技术的分类,发展历史的"分期",第二代电渣冶金技术特征.超大型电渣重熔锭及第二代液态金属浇注大型电渣锭与核电等重大装备制造业发展的关系.指出:中国在电渣重熔锭大型化发展方面,一直处于世界电渣强国地位.随着我国重大装备制造技术的迅速发展,特别是我国核电工业的迅速发展,大型锭电渣冶金技术将不断完善与发展,反过来它又必将促进我国在核电技术方面迅速赶上国际先进水平.

喷气封堵液态金属可行性实验研究

为了实现气体对液态金属的封堵约束,分别进行了喷吹气体封堵容器中水和水银侧向流出的实验。考察了喷吹气体量、喷吹距离等参数对封堵液体高度的影响。结果成功封堵水和水银,发现随喷吹气体流量的加大和喷口距离的缩短,封堵液体高度迅速增加。另外,通过回归实验数据得到封堵液体高度的经验公式。

引进消化移植钢水液面控制仪的研究

一、前言在钢铁生产过程中,能耗是生产工艺先进与否的标志之一。连铸则是改变旧生产工艺、节约能源的有力措施。目前我国已有许多厂家建了或正在筹建连铸。在连续铸钢过程中,为保证连铸机有稳定的浇注。

Experimental Modelling of the Impact of a DC Magnetic Field on the Melt Flow in a Continuous Casting Mould

This paper describes experimental investigations of flow structures and related transport processes in the continuous casting mould under the influence of an external DC magnetic field at laboratory scale.Experimental results will be presented here which have been obtained using a physical model(mini-LIMMCAST)operating with the low melting point alloy GaInSn.According to the concept of the electromagnetic brake the impact of a DC magnetic field on the outlet flow from the Submerged Entry Nozzle(SEN)has been studied up to Hartmann numbers of about 400.The Ultrasound-Doppler-Velocimetry(UDV)was applied for measurements of the flow pattern in the mould.Local conductivity anemometers were used to measure the turbulent quantities of the flow.The effect of the magnetic field on the flow structure turned out to be manifold and rather complex.The magnetic field causes a deflection of the jet,at which the respective exit angle from the nozzle ports becomes more flat.Thus,both the penetration depth of the discharging flow into the lower part of the mould and the impinging velocity of the jet onto the side wall are reduced.A significant return flow occurs in the adjacent regions of the jet.Specific vortices are formed with axes being aligned with the magnetic field direction.Such vortical structures are typical for quasi-two-dimensional magneto-hydrodynamic(MHD)flows.The flow measurements do not manifest a general braking effect which would be expected as an overall damping of the flow velocity and the related fluctuations all-over the mould volume.Variations of the wall conductivity showed a striking impact on the resulting flow structures.

The LIMMCAST Program at HZDR:Modelling of Fluid Flow and Transport Phenomena in the Continuous Casting Process

Model experiments with low melting point liquid metals are an important tool to investigate the flow structure and related transport processes in melt flows relevant for metallurgical applications.We present the new experimental facility LIMMCAST for modelling the continuous casting process of steel using the alloy SnBi at temperatures of 200-400℃.The parameters of the facility and the dimensions of the test sections will be given,and the possibilities for flow investigations in tundish,submerged entry nozzle and mould will be discussed.In addition,the smaller set-up Mini-LIMMCAST will be presented,which works with the room-temperature liquid alloy GaInSn.The main value of cold metal laboratory experiments consists in the capabilities to obtain quantitative flow measurements with a reasonable spatial and temporal resolution.New ultrasonic and electromagnetic techniques for measuring the velocity in liquid metal flows came up during the last decade allowing for a satisfying characterisation of flow quantities in the considered temperature range up to 400℃.First results from LIMMCAST and Mini-LIMMCAST will be presented covering the following phenomena:fully contacfless electromagnetic tomography of the flow in the mould,flow monitoring by a multitude of ultrasonic sensors,and analysis of the flow in the mould under the influence of an electromagnetic brake: intensification of the flow turbulence contrary to the expected flow damping,injection of argon bubbles through the stopper rod:occurrence of pressure oscillations.

The Spatial and Temporal Evolution Behavior of Fluid Flow in Round Strands Continuous Casting Under Intermittently Reversing Direction Electromagnetic Stirring

Liquid metal flow behavior in round strands continuous casting under intermittently reversing direction electromagnetic stirring was measured by ultrasonic Doppler velocity-meter in a physical simulation system in order to investigate the effects of time interval(t_i)of periodically reversed magnetic field on the spatial and temporal flow.The results show that under electromagnetic stirring with direction reserved magnetic field,there's a periodically change of the metal flow velocity and rotation direction with the periodically direction changing of the magnetic field.From both the experimental and mathematical model calculation results,it is found that when t_i is nearly equal to the time required for the metal flow speeding to the maximum velocity from still and decreases to zero again,there is a critical value of the rate of dynamic pressure,which means the wash effect of the liquid metal flow.On this point,rate of dynamic pressure was proposed to be a criterion for optimization the processing of electromagnetic stirring.

Effect of flow control mold on flow field during high-speed continuous casting

An experimental mold was built to study the flow in a flow control mold under high speed continuous casting. The effect of the magnetic field on the flow was investigated using mercury. The results show that the magnetic field can not only dampen the flow of liquid metal but also change its direction, and then redistribute the flow in the mold. When maintaining a constant distance between magnets, the fluctuation of the free surface is dampened because of the increasing magnetic flux density. The flow at the free surface is improved, and the penetration depth of the downward stream is reduced. The decrease in the dis- tance between magnets promotes the brake effect and the flow is dampened in the upper eddy.

Experimental Investigation of Fluid Flow in CC Mold With Electromagnetic Filed

Fluid flow in continuous casting mold is one of the key factors to influence the process, because the operation of the casting process and most of the defects in steel quality are closely associated with fluid flow in the mold. Electromagnetic field(EMF) has been applied to control the fluid flow as an efficient technology, and a lot of research works on the effect of the EMF has been done by numerical simulation. Aware of the limitation of the numerical simulation of the flow under a static EMF, low melting metals have been adapted to the investigation of flow in EMF. In the report, some of works on electromagnetic brake ruler (EMBR) and Flow Control Mold (FC-Mold) in slab casting with mercury as an analogue of liquid steel are presented. In the experiment, the flow in the mold and fluctuation of meniscus were measured by the ultrasonic DOP2000 velocimeter. The effects of the magnetic flux density and location of the magnets on the flow in the mold have been studied. The results showed that the flow discharged from the SEN was suppressed, both of the distribution of the kinetic energy and the turbulence intensity were changed, and the flow stability of liquid metal in the mold was enhanced. In electromagnetic brake ruler when Bmax was more than 0.29T, the surface level fluctuations were suppressed,the flow at the meniscus became stable and the flow pattern at the meniscus were improved, and the impact strength of liquid metal was weakened simultaneously, and the penetration depth was reduced. It was beneficial to improve the flow in the upper eddy, fluctuation of meniscus and stability of the flow when the magnet was located near the SEN. However, it was good to reduce the impact action and penetration depth when the magnet was away from the SEN. Compared with EMBR, it was more effective to use FC-Mold for improving the flow in the upper eddy, fluctuation of meniscus and stability of the flow. Nevertheless, it was more effective for lower flow to reducing the impact action and penetration depth using EMBR. The experiment results showed that a magnetic field could not only damp flow, but also change the flow direction and distribute the flux of liquid steel. Thus, the flow in the mold could be improved by optimizing the distribution of magnetic field. The behavior of gas bubbles in the melt during continuous casting with EMBR has been investigated experimentally. It is found that the movement and distribution of the bubbles changed a lot. The bubbles tended to penetrate less and accumulate near the SEN when the EMBR switched on.

板坯电磁制动结晶器内流体流动的研究

用Hg模拟了高速板坯电磁制动结晶器内钢液的流动,使用超声波Doppler测速仪测量了结晶器内液体的流速和液面的波动,分析了静磁场对流体流动的作用,研究了静磁场对浸入式水口出流、结晶器内金属液流动、液面波动、液面流动及对器壁冲刷强度的影响.结果表明:静磁场使浸入式水口出流受到抑制,上部环流区的流动增强,下部环流区流动减弱;改善了自由液面的波动和流动.静磁场不仅具有制动钢液流的作用,还具有改变流动方向,分配钢液流量的作用.磁感应强度大于0.29T时,更有利于改善结晶器内的流动.

第二代大型锭电渣冶金技术的发展

论述了第二代大型锭电渣重熔与液态金属电渣浇注技术的特征。提出了发展第二代大型锭电渣冶金技术的几个研究重点。指出:当前发展第二代大型锭的电渣冶金技术对推动中国大型锭锻件的自主化和核电产业的发展具有重要意义。在进一步发展大型锭电渣重熔技术的同时,要特别重视第二代液态金属电渣浇注大型电渣锭技术的开发。

中大型钢锭电渣冶金制备技术研究进展

由于电渣重熔法具有金属纯净、组织致密、铸锭表面光洁等特点,针对条件要求苛刻的中大型钢锭已广泛采用电渣重熔及其衍生技术进行生产。对电渣重熔技术、液态电渣技术、双回路电渣重熔技术、电渣熔焊技术4项中大型钢锭生产技术的原理及研究进展进行介绍和评价。随着电渣复合概念的普及,提出采用电渣铸焊技术生产中大型钢锭,并对其技术优势进行阐述。