S08A自耗电极及电渣重熔工艺试制

本文论述了优化电炉配料、选用优质石灰、精选萤石、电炉出钢换渣工艺;电渣重熔采用四元渣系,选用提纯萤石,重熔过程全程氩气保护铝粒脱氧等工艺措施,生产出低碳、低硅、低氮及残余、五害元素符合要求的自耗电极及电渣锭,经轧制成材检验低倍组织及非金属夹杂物符合技术协议要求。     

Effects of relative motion between consumable electrodes and mould on solidification structure of electroslag ingots during electroslag remelting process

Abstract

Steel solidification process control, especially in the solidification process of high alloy steel, and improvement of the solidification structure have been increasingly gaining interest among metallurgists, particularly the electroslag workers. To further develop the electroslag remelting (ESR) process and to improve the advantage of the ingot solidification structure, the effects of relative motion between the consumable electrodes and the mould (namely, mould rotation) on chemical element distribution were observed in this study, as well as the compact density changes in electroslag ingots. Experiment results show that applying relative motion between the mould and the consumable electrodes in ESR results in a more uniform chemical element distribution in the electroslag ingots. Compared with the electroslag ingot of conventional ESR, maximum segregation of carbon could decrease from 3·19 to 1·146, and statistical segregation decreased from 0·2636 to 0·0608. Maximum segregation of chromium could decrease from 1·316 to 1·253, and statistical segregation decreased from 0·2753 to 0·1201. The compact density for the stationary mould increased from 0·7693 to a compact density of 0·9501 for the rotating mould. The improvement in the solidification structure of the electroslag ingot can be attributed to mould motion, which led to the generation of a shallow pool and the improvement of the solidification structure. But the excessive rotation rate is harmful to solidification structure instead due to the molten metal pool motion caused by violent slag pool motion.     

旋转电极电渣重熔过程电极熔速的理论解析

摘要：旋转电极电渣重熔通过改变结晶器内熔体的流动和传热规律,增强了渣池与电极间的对流换热,在提高电极熔化速率和生产效率方面具有巨大潜力。提出了电渣重熔过程电极熔化速率的求解方法,并考虑了电极旋转时的强制对流,基于多物理场耦合模型预测了电极直径、转速对电极熔化速率的影响规律。结果表明,随着转速提高,金属液滴由从电极中心滴落向电极边缘滴落转变,高温区由渣池外侧向渣池中心移动。当转速从0增大至90r/min,55mm直径电极的熔化速率从7.90g/s增大至9.68g/s,对比固定电极,转速为90r/min时,生产效率最多提高了22.5%;进一步增大转速,电极熔化速率反而减小。存在一个最佳转速可使熔化速率达到最大,且该最佳转速随着电极直径的增大而减小。     

Numerical investigation on the fluid flow and heat transfer in electroslag remelting furnace with triple-electrode

Electroslag remelting (ESR) furnace with triple-electrode is always used to produce large ingots and the process complexity makes the application not widely spread. Thus, a transient three-dimensional coupled model in industrial scale has been developed to investigate the coupled magneto-hydrodynamics two-phase flow and heat transfer in system. Different from the previous studies with multi-electrode, the current work reveals the triple-electrode ESR with the formation of metal droplets and the solidification of liquid metal. Compared with single-electrode system with the same fill ratio, the heat source in the slag pool with triple-electrode is much more dispersive, and the U-shape metal pool in the ESR furnace with triple-electrode is much shallower and flatter than the V-shaped one in the single-electrode system. A shorter distance from each electrode to the center of system brings a higher heat efficiency, as well as a deeper and narrower metal pool.     

现代电渣重熔先进技术特征与演进

 电渣重熔是制备高端特殊钢和合金的关键冶炼工艺,在铸锭质量和成材率方面优势明显。随着中国装备制造业的快速发展,对所用钢及合金的质量和性能要求不断提高,而传统电渣重熔技术面临电耗高、产品质量稳定性差等问题。现代电渣冶金技术的发展核心在于浅平熔池形状的稳定控制和杂质元素的高效去除,目标是更高洁净度、更高凝固质量和更高生产效率。为了让国内冶金工作者了解目前电渣重熔技术的最新发展动态,助力中国电渣冶金技术的开发和应用,综述了近年来国内外相继涌现的先进技术与理论,分析了国内外在相关技术的应用特征和演进方向。中国在电渣炉设备制造、气体保护电渣重熔技术、同轴供电技术和结晶器导电技术方面基本与国际先进水平同步,但尚未形成完善可靠的渣系配置理论、精炼过程的热力学及动力学理论,较国外仍有差距,这已成为限制电渣产品质量提升的主要因素之一。低频电源技术、真空电渣重熔技术和旋转电极电渣重熔技术具有极高的工业化应用前景,需要进一步明确其对工艺过程和产品质量的影响规律。摆动控制已成为国际先进电渣企业的主流控制技术,却是中国电渣炉设备制造的短板,借助在线检测和模拟仿真技术的恒熔池形状控制技术是中国电渣冶金控制技术的发展方向。     

电渣重熔过程中氢行为的分析及控制

分析了电渣重熔过程中氢的行为,分别讨论了大气湿度、渣中的水分、电极的w(H)及炉渣成分对铸锭中氢行为的影响,提出了相应的控制措施.     

连铸钢水快速精炼工艺实践

通过在吹Ar合金微调站加入Al脱氧和SiCa对夹杂物变性,选择合适的造渣剂CaO-SiO₂-CaC₂以及软吹Ar工艺,可以在不影响连铸机匹配的条件下(18min内)使钢水中活度氧降低到20×10^-6以下,渣中的FeO+MnO<3%,而连铸浇注时不会发生水口堵塞现象.满足了马鞍山钢铁公司第三钢轧总厂从美国新引进的使用油润滑浇铸的小异形坯连铸机对钢水质量和生产匹配的要求.     

Effect of electrode change on solidification of slag and metal pool profile in electroslag remelting process

A two-dimensional axisymmetric model is established to study the effect of electrode change on the solidification of slag and metal pool profile during electros...     

Distribution law of flow field and temperature field in electroslag remelting withdrawal process

A three- dimensional mathematical model was developed to describe the interaction of multiple physical fields during the electroslag remelting withdrawal (ESRW) process. Flow fields and temperature fields of the ESRW system were simulated by commercial software ANSYS. The flow fields, temperature fields and the shapes of the molten pool during the ESRW process with different electrode immersed depths and slag heights were analyzed and compared. The temperature of ingot surface was measured, and the accuracy of simulation results was verified. The results show that there are two pairs of vortexes in slag bath during the ESRW process. A pair of large vortexes turns counterclockwise, and another pair of small vortexes rotates clockwise. The speed of slag increases with the increasing of immersion depths of the electrode, and decreases with the increasing of slag heights. There are two high temperature zones in the slag bath, and the temperature in the slag bath is higher than that in the metal bath. The temperature of ESRW system (electrode, slag bath and ingot) becomes higher with the increasing of immersion depths of the electrode, whereas becomes lower with increasing of slag heights.     

Increasing the efficiency of the electroslag process and improving the metal quality by rotating a consumable electrode: Part 1

The effect of centrifugal forces on the melting, transport, and solidification of a metal during electroslag remelting of a consumable electrode is comprehensively studied, and the parameters that can increase the technical and economic indices of remelting and the metal quality are revealed.     

RH精炼过程钢液流动数值模拟和应用

结合某钢厂RH精炼装置,运用数值模拟的方法对脱气时的流场进行了计算,得出了该型号RH装置在该厂操作条件下的流场,并成功解释了操作中遇到的一些现象.利用实践生产中的经验公式与数据对模拟结果进行了验证,结果表明模拟结果可靠.最后利用该模型计算了RH内钢液的湍动能耗散情况以及钢液循环流量与吹Ar量的关系,并给出了最佳吹Ar量的控制范围.     

优化条件的RH流场数值模拟研究

采用欧拉模型数值模拟方法,通过采用更接近实际的边界计算条件和初始条件对170tRH熔池流场进行了模拟分析。研究结果表明：改进后模型计算出的流场状态和循环流量结果与试验结果很一致;上升管内钢液速度呈M型分布,且气泡在上升管内的流动具有波动性,下降管内钢液流速度分布均匀,上升管内壁比下降管内壁更容易侵蚀。     

高碳熔铁脱磷的实验研究

选择ＣａＯ－ＳｉＯ２－ＦｅＯ为基本渣系,对高碳熔铁脱磷进行实验,研究了高碳熔铁脱磷过程中碳和磷的变化,比较在不同温度和溶剂的条件下,对高碳熔铁脱磷的影响．实验表明：熔铁初始碳含量的高低对前期脱磷影响不大．但终点碳含量的高低影响回磷．ＢａＯ在高碳脱磷过程中能有效地抑制回磷．     

铜精炼炉保温过程铜液温度软测量模型及应用

基于铜精炼炉保温过程热工机理,建立了铜精炼炉保温过程铜液温度软测量模型,在铜液温度软测量的算法设计中采用数据预处理、黄金分割法搜索区间及其函数链神经网络在线校正等技术。实际应用结果表明,铜精炼炉保温过程铜液温度软测量可以反映保温过程铜液温度的真实变化,有助于实现铜精炼炉精炼过程铜液温度软控制以及提高铜精炼过程的生产效率和生产质量。     

银电解精炼的技术改进及展望

本文总结了叙述了１９８３年以来沈阳冶炼厂银电解精炼过程技术改进，包括提高电银质量，钛阴极的应用，电解液的组成等，并对银电解精炼过程的继续改进提出建议。     

离子液体电解质体系铝及铝合金电沉积与铝精炼研究进展

传统上,铝、稀土和碱金属及碱土金属等活泼金属主要是通过高温熔盐电解法得到,其电解工艺流程能耗高.近几年来,对离子液体的不断深入研究,提出离子液体为电解质体系用于金属铝、铝精炼和铝合金.综述目前采用离子液体体系进行铝及铝合金电沉积,粗铝、铝合金和铝基复合材料电解精炼回收铝的研究现状和研究进展.介绍和评述离子液体电解质电沉积、精炼铝的应用情况和所取得的研究成果,探讨离子液体电解质用于铝行业的发展趋势和研究动向.      

Numerical simulation of solidification structure during electroslag remelting casting of ZG06Cr13Ni4Mo ingot based on CAFE and moving boundary method

A comprehensive mathematical model of the solidification structure during the process of electroslag remelting casting (ESRC) of low carbon martensite stainless steel ZG06Cr13Ni4Mo has been established. The change of metal pool profile and grain growth and the microstructure evolution process from the beginning to the steady stage of the ESRC process were investigated by using the moving boundary method and the coupled technology CAFE method (cellular automaton – finite element method). The transition from equiaxed grains at the lateral wall of the mould to columnar grains has been revealed. In addition, casting of this steel has been carried out and the microstructure of the ingot obtained after grinding and acid leaching. According to the comparison of the metal pool profile, morphology and growth direction of the dendrite and the secondary dendrite arm spacing (SDAS) between the experimental results and the simulation results, the validity of the model has been demonstrated, which can provide a favourable theoretical foundation to optimise the process parameters for the control of solidification structure of ESRC of low carbon martensite stainless steel ZG06Cr13Ni4Mo.     

不定型TiO_2薄膜修饰电极的制备及其电极过程动力学特性

通过熔胶一凝胶法在ITO导电玻璃基片表面制备一层TiO2薄膜,将其在空气中分别进行150℃×2h,200℃x2 h和250℃×2 h的热处理,形成不定型TiO2薄膜修饰电极.用X射线衍射仪和扫描电镜对薄膜结构和形貌进行了表征.将该修饰电极作为工作电极,与作为参比电极的饱和甘汞电极、作为辅助电极的铂黑电极、作为电解质溶液的碳酸丙烯酯+高氯酸锂一起构成三电极测试体系.根据该电极的循环伏安曲线测试结果讨论了该电极过程的动力学特征,分析了扫描参数和薄膜的热处理温度对电极过程动力学的影响.     

先进镀锌高强钢中液态金属脆化的研究进展及挑战

先进高强钢广泛用于汽车车身结构,能够在保证车辆安全性的同时使整体车身减重,满足节能减排的要求,在汽车轻量化方面已凸显出巨大的应用潜力.通常汽车用高强钢板需要进行表面镀锌处理以提高车身结构的抗腐蚀能力.但镀锌高强钢板在点焊过程中容易产生液态金属脆化,降低焊接接头的承载性能.镀锌热成形高强钢在热成形过程中也会产生液态金属脆...     

高温金属流体的测量与控制系统

液态金属温度高、腐蚀性强 ,流量不能直接测量和控制 ,本文提出了用神经网络建立液态金属重量与流量的数学模型 ,对液态金属流量进行软测量的检测方法 ,再用两级计算机控制系统 ,实现液态金属流量的稳定控制。仿真和实际应用结果表明 ,用该方法检测高温液态金属流量的相对误差小于 1.5 % ,满足实际生产要求。