Heat Transfer Analysis for Industrial AC Electric Arc Furnace

The heat transfer analysis was performed for an AC electric arc furnace (EAF). Heat losses by conduction, convection and radiation from outer surface, roof, bottom and electrodes of EAF were determined in detail. Some suggestions about decreasing heat losses were presented.     

EBT区域底吹流量变化对电弧炉炼钢的影响

 电弧炉底吹是加速熔池流动、减少EBT区域死区、改善炼钢反应的重要手段,底吹流量变化会影响电弧炉熔池流动和冶金效果。利用Fluent软件研究了100 t电弧炉EBT区域附近不同底吹流量的熔池流动特性,发现当EBT区域底吹流量从100增加至150 L/min时,熔池平均流速提高18.03%,死区面积减少22.06%;当进一步增加至200 L/min时,熔池流速和死区面积变化幅度降低。在此基础上,通过100 t电弧炉炼钢试验研究了不同底吹条件下的冶金效果,发现底吹可显著降低电弧炉钢铁料消耗和石灰消耗,缩短冶炼周期,降低炉渣FeO质量分数和钢液碳氧浓度积;随着EBT区域底吹气体流量从100增加至150 L/min,冶金效果进一步得到改善。     

Development of the process of electric steel production and methods for improving the technical-and-economic indices of electric arc furnaces

The structure of the metal losses during melting of a low-carbon semiproduct in EAF is analyzed. It is shown that a further increase in the capacity of a modern superpower EAF can degrade the technical-and-economic indices of its operation. The increase in the metal losses in melting in EAF is caused by a high oxygen flow rate and a number of other technological factors. The rational methods of increasing the technical-and-economic indices of EAF are a decrease in the metal losses in melting and processing of the semiproduct, a decrease in the primary energy consumption, and the recycling of dust and waste slags.     

电弧炉EBT区不同底吹搅拌条件的钢液流动数值模拟

底吹工艺在电弧炉炼钢过程中的应用能有效缩短熔池混匀时间, 加速碳、磷、硫的去除, 提高生产效率及产品质量.本文利用数值模拟软件模拟了EBT (偏心底部出钢) 区底吹孔不同气体流量下的电弧炉钢液速度场, 发现当EBT区域底吹气体流量从100 L·min^-1升至267 L·min^-1 (其他两孔气体流量稳定保持为133 L·min^-1) 时, EBT区域钢液的平均流速由2.805×10^-3m·s^-1升至3.268×10^-3m·s^-1, 钢液整体平均流速由4.126×10^-3m·s^-1升至4.610×10^-3m·s^-1, 并耦合得出EBT区域不同底吹流量下的钢液流动速度经验公式.由于钢液流动是影响熔池内反应的动力学因素, 本文提出了电弧炉炼钢基于底吹熔池搅拌的碳成分预报模型, 为冶炼终点均匀熔池成分、合理供氧操作提供理论建议.     

Metal losses and the heat-and-mass transfer in the working space of superpower arc steelmaking furnaces

The heat-and-mass transfer in the working space of an electric arc furnace (EAF) is analyzed on the basis of the real metal losses in industrial furnaces. The energy exchange between the arc discharge and the environmental space of the surface filled with the radiating and absorbing vapor-dust-gas medium is shown to change. The processes of metal evaporation and vapor condensation in the working space of EAF are considered.     

Advances in Modern EAF Steelmaking Technology of China

In the recent decade, the remarkable achievements have been made on steelmakingtechnology with electric arc furnace (EAF) in China, on the basis of importing and assimilatingnew technologies from abroad and making innovation. The integrated control theory of tap-to-tap time and electric power consumption of modern EAF was put forward and hence showed theresearch direction to shorten tap-to-tap time, decrease electric energy consumption and increaseproductivity and the basis to select rated power of transformer. EAF steelmaking technologywith hot metal charging, terminal point control (TPC) technology, bottom blowing technologywith nitrogen instead of argon and low nitrogen steel producing technology were obtained. Fi-nally, the structure model of raw materials was presented.     

吹氩工艺在电弧炉炼钢中的应用

HP4 5t(EBT)电弧炉是北钢 1990年由法国引进 ,西德克鲁伯公司制造 ,经改造成为EBT出钢方式的一台固定式电弧炉 ,就在其配套精炼设备 6 0tLF炉上的生产实践 ,论述吹氩工艺在炉外精炼中的应用。     

电弧炉炼钢成分预报现状与熔池搅拌对其影响

电弧炉炼钢成分预报与控制直接影响冶炼时间、产品质量与生产成本,是电弧炉炼钢智能化的重要环节。对转炉、电弧炉副枪检测技术和炉气分析技术进行了分析,探讨了炼钢过程的选择性氧化机理与智能算法在成分预报中的应用。结合熔池流动慢、反应不均衡的动力学条件,讨论了电弧炉炼钢成分预报的难点。在国内外文献综述的基础上,讨论了电弧炉底吹搅拌、氧气射流及电磁流体对钢液流动的影响,提出将电弧炉熔池钢液流动行为的动力学影响和炼钢反应选择性氧化热力学相结合,实现成分实时预测研究的设想,对开展电弧炉炼钢成分预测研究具有指导意义。     

不锈钢EAF渣无害化处置及作为水泥基材料的工程性能

 不锈钢电弧炉(EAF)渣具有胶凝活性,其主要化学成分及矿物组成与水泥材料相似,可作为水泥基材料加以利用。但不锈钢EAF渣中含有一定量的CaCrO4使其存在六价铬浸出风险。利用碳热还原干式解毒法对EAF渣进行无害化处理,对还原温度、配碳量及碱度进行控制,可有效将电炉渣中铬氧化物还原。还原后渣中CaCrO4相消失,总铬及六价铬浸出值明显低于标准限值。对解毒后EAF渣进行胶凝性能测试,其活性指数、凝结时间均符合GB/T 20491—2006规范要求,可应用于建材领域以达到安全排放及资源化利用目的。     

搅拌部位及强度对底吹电弧炉熔池混合特性的影响

在３０Ｔ底吹电弧炉１：７水模型的基础上，研究了搅拌部分对ＫＣｌ溶液电导率值变化的影响及熔匀时间与搅拌功率密度的关系，作出了溶液等混匀时间曲线。结果表明，底部吹气搅拌可强化电弧炉熔池的均匀混合，其混合速度底部快于表面，中心快于边缘     

电炉除尘兼余热回收系统的设计与应用

为满足可持续发展的要求,莱钢自行研制并设计了电炉除尘兼余热回收装置,且在50 t超高功率电弧炉上得到成功应用。该系统在满足环境净化要求的同时,利用收集的烟尘热量生产出高温高压蒸汽,满足了VD生产和职工生活的需要,为国内电炉节能降耗和清洁生产进行了有益的探索,填补了国内电弧炉余热利用的空白。     

EAF Stainless Steel Refining ‐ Part II: Microstructural Slag Evolution and its Implications for Slag Foaming and Chromium Recovery

The microstructural evolution of the slag during the electric arc furnace (EAF) austenitic stainless steelmaking was investigated with respect to its effect on chromium recovery and slag foaming. Two distinct EAF types were followed up: (1) an eccentric bottom tapping furnace (EBTF) and (2) a spout tapping furnace (STF). Slag samples were collected from 36 industrial heats at three (EBTF) or five (STF) distinct moments in the process. The microstructure of the slag samples was characterised with electron probe microanalysis using energy dispersive spectroscopy (EPMA‐EDS) and X‐ray diffraction (XRD). From the microstructural analysis it is concluded that at the processing temperature the slag consists of a liquid slag matrix, two different types of metallic particles and MgO·(Al,Cr)₂O₃‐based spinel particles. The evolution of the microstructure is highlighted, the interactions between the phases are discussed and the effects of changing conditions on the slag microstructure are illustrated by thermodynamic calculations. Special attention is given to the effect of slag basicity on the activity of chromium oxide in the slag. It is shown that a thorough study of the microstructural evolution of the slag is instrumental to understanding and improving slag foaming and chromium recovery.     

现代炼钢流程冶炼工序的共性问题

论述了现代炼钢流程冶炼工序即转炉冶炼和电炉冶炼的共性问题;指出了二者在功能演变、原料结构、能源结构、终点控制、底吹氮、经济性评价及对生产钢种的适应性等方面存在共性;讨论了二者之间共性对中国钢生产发展的影响.并强调电炉流程与转炉流程在一相当长的时间内会共存,转炉钢与电炉钢的比例会有所变化,电炉钢的比例虽比不上世界电炉钢比的水平,但会逐步增加.     

电炉炉底用MgO－CaO－Fe_2O_3合成砂的研制与应用

ＭｇＯ－ＣａＯ－Ｆｅ_２Ｏ_３合成砂构筑的电炉炉底，表面形成的氧化层不断地消失和再生，体现了陶瓷结合相进入主晶相和形成高熔点矿物的结构特征，从而实现长寿命炉底。     

电弧炉氧和固体燃料不同喷吹设备的比较

本文叙述了利用数控机床的计算机诊断功能和电气原理图来排除其故障的方法。     

世界直流电弧炉的发展和我国电弧炉炼钢现代化

对信号继电器的接线方式做了一些改进，使之达到了准确无误的动作。     

超纯轴承钢的精炼工艺

通过控制电炉(供氧强度、渣中氧化铁比例、出钢挡渣率、出钢钢液的氧活度)、钢包炉(精炼渣系、脱氧剂、钢液温度、精炼时间、底吹氩压力、精炼钢包耐火材料的选择、铁合金种类的选择)、真空脱气(真空度、真空时间、底吹氩压力)的工艺参数以及真空后的软吹氩搅拌、并采用IPAS系统和控制钢液浇铸速度,使超纯轴承钢(SFGCr15)的w(S)、w(Ti)、w(O)分别达到0.003%、0.001 2%和0.000 7%以下,钢中非金属夹杂物也处于较好水平,满足了国际顶尖轴承厂家对轴承钢的超纯要求.     

EAF Stainless Steel Refining ‐ Part I: Observational Study on Chromium Recovery in an Eccentric Bottom Tapping Furnace and a Spout Tapping Furnace

An observational study of the electric arc furnace (EAF) process for austenitic stainless steel was performed. A comparison was made between two distinct EAF types: (1) an eccentric bottom tapping furnace (EBTF) and (2) a spout tapping furnace (STF). In order to study the slag evolution during the EAF process, per heat several slag samples were collected at consecutive process stages. They were subjected to electron probe microanalysis using energy dispersive spectroscopy (EPMA‐EDS). Compositional and mineralogical data from 36 heats corroborate that both thermodynamic and kinetic conditions exert a strong influence on the final chromium oxide content of the slag. In the STF, chromium oxide reduction predominantly occurs during tapping, owing to the intimate mixing of steel and slag. A multivariate linear regression analysis reveals that the main parameters determining the overall chromium recovery are the slag basicity and the content of dissolved silicon of the steel. These parameters explain 70% of the observed variance in final chromium oxide levels and can be used as control parameters to improve the chromium recovery. For the EBTF, lower chromium recoveries are recorded due to the absence of sufficient mixing during tapping.     

直流电弧炉几种型式炉底电极的比较与评价

从安全、导电、绝缘、搅拌、偏弧、炉子吨位，冷却方式与允许电流密度，砌筑与维修方式，起动方式，炉底电极寿命及费用等十几个方面对直流电弧炉不同型式炉底电极进行了综合比较与评价，指出每种型式炉底电极都各有优点和缺点，绝对肯定或否定哪种型式都不恰当，用户可以根据自己的认识与工厂的实际情况选择合适的炉底电极型式。对我国直流电弧炉的发展提出了几点建议。     

Simulation and application of pulsating bottom-blowing in EAF steelmaking

Pulsating bottom-blowing was proposed to strengthen the electric arc furnace (EAF) molten bath stirring. The fluid flow characteristics and stirring effects of different pulsating bottom-blowing modes on EAF molten bath were studied through water model experiments and numerical simulations. The mixing time was measured by water model experiments and the flow field characteristics of EAF molten bath were simulated by numerical simulations. Compared with conventional bottom-blowing, pulsating bottom-blowing can accelerate the fluid flow velocity and improve the stirring of molten bath. With pulsating bottom-blowing, the molten bath fluid flow field is more disorder, the fluid flow velocity increases and the dead zone volume decreases. Compared with EAF steelmaking with conventional bottom-blowing conditions, pulsating bottom-blowing technology can improve the metallurgical effects and the molten steel quality in EAF steelmaking with lower FeO content of final slag, lower phosphorus content and carbon-oxygen equilibrium of final molten steel, and lower temperature deviation.