活性石灰在钢水精炼中的应用

介绍了在钢水精炼过程中,添加一定量的活性石灰和萤石,提高精炼钢水顶渣的碱度,降低熔渣的熔点,改善熔渣的流动性。消除钢包内衬结渣挂渣、顶渣结壳的现象,以及AHF浸渍罩、RH上升管和下降管结渣上涨的现象。同时钢水精炼添加活性石灰后,有一定的脱硫和吸附一定量钢中夹杂物的作用。     

Effect of Foaming Temperature on Bubble Size Distribution of Liquid Aluminium Foam: Modeling and Experimental Studies

The present study examines the effect of foaming temperature on the final foam expansion and the bubble size distribution of liquid aluminium foam through mathematical modeling and validation experiments. The model calculates the rate of hydrogen release from the foaming agent (TiH₂) particles, super saturation of the melt, nucleation and growth of bubbles and finally, evaluates the evolving bubble size distribution using a population balance approach. The model does not consider bubble coalescence and breakage and uses only solute diffusion for bubble growth. The simulation is performed for two conditions; firstly, for pure temperature effects and secondly, for temperature and TiH₂ quantity combined effects. Upon comparison of simulation results with the experiments, following important observations are made; firstly, the predicted total number of bubbles is found to be one order of magnitude higher than the experiments while the predicted average size is one order of magnitude lower. Secondly, the spread of the predicted distributions is observed to be much narrower. These discrepancies are considered to be due to bubble coalescence and coarsening which are not modeled and shown to be strongly influenced by the foaming temperature.     

High Temperature Deformation Behavior of 4340 Steel: Activation Energy Calculation and Modeling of Flow Response

The 4340 steel is extensively utilized in several industries including automotive and aerospace for manufacturing a large number of structural components. Due to the importance of thermo-mechanical processing in the production of steels, the dynamic recrystallization (DRX) characteristics of 4340 steel were investigated. Namely, hot compression tests on 4340 steel have been performed in a temperature range of 900–1200 °C and a strain rate range of 0. 01–1 s^?1 and the strain of up to 0. 9. The resulting flow stress curves show the occurrence of dynamic recrystallization. The flow stress values decrease with the increase of deformation temperature and the decrease of strain rate. The microstructure of 4340 steel after deformation has been studied and it is suggested that the evolution of DRX grain structures can be accompanied by considerable migration of grain boundaries. The constitutive equations were developed to model the hot deformation behavior. Finally based on the classical stress-dislocation relations and the kinematics of the dynamic recrystallization; the flow stress constitutive equations for the dynamic recovery period and dynamic recrystallization period were derived for 4340 steel, respectively. The validity of the model was demonstrated by demonstrating the experimental data with the numerical results with reasonable agreement.     

重塑钢铁冶金短流程

介绍了典型的钢铁冶金长流程和短流程的生产工艺,针对我国天然气缺乏的实际情况,阐述了我国钢铁工业重塑中国式的钢铁冶金短流程的必要性.提出了儿种适台我国钢铁工业实际情况的钢铁冶金短流程新模式.     

钢液二次精炼中CaO基熔剂脱磷效果的研究

在实验室条件下,利用CaO-Fe2O3-CaF2系熔剂进行钢液二次精炼脱磷工艺实验,测定CaO基熔剂添加量以及熔剂中加入SiO2、Al2O3和转炉渣时对钢液脱磷效果的影响关系。结果表明,对于优化组成的CaO基熔剂,通过控制相关脱磷影响参数,仍可得到大于90％的脱磷率,能将钢液ω(P)从0．05％降低到0．005％以下。     

单嘴精炼炉真空处理过程钢液流动行为模拟研究

根据相似理论,以国内某厂80t单嘴精炼炉1:4的水模型模拟了单嘴精炼炉吹气流量、吹气位置等工艺参数对混匀时间的影响.在水模型研究的基础上,通过数学模型仿真计算分析了不同吹气流量、吹气位置对单嘴精炼炉内流场的影响,数值计算结果与试验结果吻合较好.研究结果表明:吹气流量为6L/min、吹气位置γ/R为0.5范围内有利于缩短...     

高压底吹条件下钢液中气泡的物理模拟

为了推断高压条件下气体在液体金属中的存在形态和运动形态,通过水模拟试验研究压强、底吹流量对气泡形状、尺寸、数量及"渣眼"尺寸的影响,结果表明:随着底吹流量增加,高压条件下的气泡比常压条件下的气泡更趋向于正圆形,气泡直径平均值变小,气泡数量增多,气泡形状和直径在底吹流量为4 L/h时变化最为明显;当底吹位置和底吹流量不变时,随着压强的增加,气泡形状逐渐趋向于正圆形,气泡直径逐渐变小,气泡数量逐渐增多,"渣眼"面积逐渐减小。在常压和高压条件下,底吹流量超过5 L/h之后,气泡形状和直径平均值就不再有明显变化。当底吹流量为4 L/h时,压强升高到0.5 MPa后,气泡形状和直径平均值变化幅度较小。为高压条件下冶炼提供数据参考。     

Mathematical Modelling of Molten Steel Flow Process in a Whole RH Degasser during the Vacuum Circulation Refining Process: Mathematical Model of the Flow

A three‐dimensional mathematical model for the molten steel flow in a degasser during the RH refining process has been proposed and developed. The physical characteristics of the process, particularly the behaviour of gas‐liquid two‐phase flow in the up‐snorkel and the momentum exchange between the two phases are considered. The ladle, snorkels and vacuum vessel are regarded as a whole in the model, and the gas‐liquid two‐phase flow is treated and described on the basis of the two‐fluid model and using the especially modified two‐equation κ‐? model. The details of the model are presented.     

RH-MFB精炼过程钢包内钢液流动与碳浓度分布的模拟研究

根据某厂RH-MFB的生产实际,采用CFX软件建立钢包内钢液流动与碳浓度分布的耦合数学模型,对钢液的流动特性以及碳浓度的分布情况进行研究,利用现场数据验证所建模型,分析了脱碳后期钢液碳浓度的分布情况,考察了工艺设备等因素对脱碳处理过程的影响,为超低碳钢的工艺优化提供理论依据和指导.     

Model of Desulphurization of Steel Melts in Ladles – Deoxidation and Slag Formers Calculation

The authors present their own model applicable for effective desulphurization of steel by ladle treatment. The model is based on a thermodynamic approach (equilibrium data) and technological data (correction factors). It consists of two parts. In the first part the authors present the formulae derived for estimation of the additions of deoxidation agents which ensure sufficiently low oxygen level prior to the desulphurization process, while the other part gives a qualitative and quantitative selection of slag formers to achieve low final levels of sulphur in steel. For the deoxidation process two variants were considered: (i) with Al only (for low silicon steels) or (ii) Al‐Si (for silicon steels) as deoxidizers. For the desulphurization process three variants were assumed as to ladle slag composition: (i) slag consisting of a fraction of furnace slag, lime addition and deoxidation products, (ii) slag made of synthetic CaO–Al₂O₃ and (iii) slag based on lime and fluorspar. The model formulae for desulphurization were derived using the sulphide capacity concept which relies on the optical basicity. In addition, rough estimates of the slag liquidus temperatures are given. A numeric example of the model application and the model algorithm (appendix) are enclosed.     

借助边缘环布碎焦和中心加焦控制高炉内气流分布

分析了高炉边缘环布碎焦和中心加焦对气流分布的控制作用。中心加焦可促进中心气流发展，减轻煤气对炉墙的冲刷；环布碎焦可有效隔热且避免矿石结炉墙。此两项措施并用可使高炉内气流分布合理，侵蚀减缓，结果消除、热损失减少，有利于节能。     

搅拌器的结构参数对钢液内电磁场和流场分布的影响

利用ANSYS5．6软件对单侧线性电磁搅拌作用下钢液内的电磁场分布和流场分布进行了数值模拟,分析了搅拌器的结构参数对钢液流动状况的影响,结果表明,在搅拌器长度,线圈匝数及电流强度均相同的条件下,采用集中绕组的搅拌器所产生的电磁场最弱,而重叠绕组搅拌器和克兰姆绕组搅拌器的电磁利用率较高,所产生的磁场强度越大,钢液的流动速度和紊流动能均较大;此外,尽管磁轭不影响电磁场的分布趋势,但却显影响磁场强度的大小,所以,在数值模拟中应当考虑磁轭的存在,当搅拌器极距和其它参数一定时,增加搅拌器长度有利于扩大搅拌的作用范围,但对提高搅拌无明显效果,在搅拌器长度和其它参数一定的情况下,增大搅拌器的极距却不影响搅拌的作用范围,但却使搅拌强度明显提高。     

莱钢H13模具钢的研究开发

介绍了莱钢研究开发高品质H13热作模具钢的过程，采用电炉→LF、VD精炼→钢锭→电渣重熔→锻造工艺生产的H13钢在做了大量检验分析后，质量性能优良。     

Physical and Mathematical Modeling of Flow Structures of Liquid Steel in Ladle Stirring Operations

Metallurgical and Materials Transactions B - Flow structures of liquid steel during stirring operations with argon injection in a ladle are studied using physical and mathematical models. Emphasis...     

Modeling of Liquid Steel/Slag/Argon Gas Multiphase Flow During Tundish Open Eye Formation in a Two-Strand Tundish

Metallurgical and Materials Transactions B - Multiphase flows are frequently encountered in metallurgical operations. One of the most effective ways to understand these processes is by flow...     

Influence of Material Flow in Steel Manufacturing Process on Atmosphere Environmental Load

The standard material flow diagram in steel manufacturing process was proposed to analyze the influences of various material flows on environmental load of 1 t of final product.Two influence factors and reducing measures of environmental load were pointed out. The environmental load was appraised for a typical technological process in a Chinese steel plant.     

关于钢铁制造流程与产品优化问题的讨论

分析了钢铁制造流程和生产技术的发展现状,提出了21世纪我国钢铁工业优化钢铁制造流程、调整产品结构、提高产品质量以及节能、降耗、环保的新理念。     

Effect of Tank Size and Geometry on the Flow Induced by Circular Bubble Plumes and Water Jets

Ambient flow field and circulation patterns induced by circular bubble plumes and water jets in tanks of different sizes were studied in rectangular and square water tanks. A nonstationary nature of the flow was observed in all experiments and its dominant oscillation frequency was found to directly relate to the tank size. The flow circulation patterns were similar for bubble plumes and water jets, but changed significantly with tank size and geometry. Strong three-dimensional effects were observed in a rectangular tank, resulting in flow entraining in the longer plane and flow detraining in the shorter plane, especially for the bubble plume tests. A relationship was developed to relate the tank size to the patterns of circulation cells. Nearly isotropic turbulent flow conditions were obtained in all experiments, but the effect of tank size and geometry on the magnitude of the turbulent stresses was more pronounced in the bubble plume tests.