二冷区辊式电磁搅拌在安钢板坯的试验和应用

依据制定的正交试验表,进行电磁搅拌工艺试验。通过酸蚀检验铸坯低倍试样和钻孔分析元素的偏析指数,确定了安钢第一炼轧厂二冷区辊式电磁搅拌的最优工艺参数。生产应用实践表明,该辊式电磁搅拌器可以明显改善铸坯的凝固组织,提高铸坯的内部质量。     

行波磁场铸流搅拌提升不锈钢板坯等轴晶率

为揭示各种行波磁场铸流搅拌的电磁冶金效果,基于计算域分段法建立了断面1280 mm×200 mm板坯连铸电磁、流动、传热和凝固的耦合模型,利用电气参数和磁感应强度的实测值和预测值的对比验证了模型的可靠性。研究表明:行波磁场搅拌器因电磁推力的方向性特点在板坯二冷区搅拌过程中均表现有不同程度与特征的端部效应,辊后箱式搅拌器(Box-typed electromagnetic stirrer, B-EMS)的单侧安装形式导致板坯内弧侧磁感应强度远大于外弧侧,辊式搅拌器(Roller-typed electromagnetic stirrer, R-EMS)的对辊安装形式则使磁感应强度呈现对称分布。在400 kW和7 Hz的相同电气参数下,R-EMS的电流强度比B-EMS高75 A;尽管箱式电磁搅拌的有效作用区域较辊式电磁搅拌大,铸坯中心钢液过热耗散区域大,但辊式搅拌推动钢液冲刷凝固前沿形核作用则明显大于箱式搅拌。两者均具有较好的抑制柱状晶生长、促进凝固前沿等轴晶形核与发展的能力,将不锈钢板坯等轴晶率提高至45%的门槛值以上,其中间隔型反向辊式搅拌器下的等轴晶率比箱式搅拌高约17%。综合表明,基于行波磁场铸流搅拌的间隔型反向辊式搅拌器有望更好地消除铁素体不锈钢板材表面皱折缺陷。      

两对二冷电磁搅拌对无取向硅钢铸坯等轴晶率和热轧板组织的影响

通过电磁搅拌力计算及工业试验,研究了两对二冷电磁搅拌器在不同搅拌参数及组合方式下50W800无取向硅钢的铸坯等轴晶率及热轧板组织。结果表明,两对搅拌辊搅拌参数一致时,搅拌参数均为380A/6Hz的铸坯等轴晶率最高,为23.48%;两对搅拌辊搅拌参数不一致时,第一对搅拌参数为380A/6Hz和第二对搅拌参数为350A/3Hz的铸坯等轴晶率最高,为25.42%。随着铸坯等轴晶率的增加,热轧板表层的再结晶晶粒尺寸逐渐增加,1/4厚度处和心部的纤维组织明显减少,且1/4厚度处再结晶晶粒的数量增加、尺寸增大。综合考虑增加铸坯等轴晶率和热轧板晶粒尺寸、减少热轧板带状组织以及降低电能消耗,第一对搅拌辊的搅拌参数为380A/6Hz和第二对搅拌辊的搅拌参数为350A/3Hz为最优搅拌参数组合方式。     

无取向电工钢XG800WR连铸电磁搅拌试验研究

采用铸坯低倍组织检验和化学分析的方法,研究板坏连铸机二冷区电磁搅拌器电流和频率参数对无取向电工钢XG800WR板坯中心偏析和等轴晶率的影响,结果表明:铸坯等轴晶率随着搅拌器电流强度和电流频率的增大而增加.采用二冷区电磁搅拌可减小中心易偏析元素S的偏析,试验得出:减小铸坯S偏析效果最好的电磁搅拌参数为电流380～400A...     

连铸机电磁搅拌器的故障探析及改进对策

对舞钢公司新线炼钢3#连铸机安装辊式电磁搅拌器在使用过程中的故障原因进行了分析,并提出了改进对策,改进后延长了电磁搅拌辊的在线使用周期,提高了铸坯质量。     

电磁搅拌技术在板坯连铸中的应用

介绍了电磁搅拌技术的原理、电磁搅拌器的分类、电磁搅拌装置的应用条件,河北敬业集团板坯连铸机在二冷区应用双辊电磁搅拌器后,铸坯中心获得了较宽的等轴晶带,减少了中心疏松和中心偏析,改善了铸坯表面及内部质量,取得了较好效果。     

提高板坯连铸水平的最新进展达涅利罗特莱克辊式电磁搅拌装置

辊式电磁搅拌器是一种装在厚板坯连铸机结晶下面或铸流上，具有特殊结构形式的电磁搅拌装置（S-EMS）。目前，世界上有各种各样的S-EMS结构形式。对于所有这些结构形式，冶金目的都是与没有安装电磁搅拌器的传统式板坯连铸机相比，在铸坯内部能够获得更为均匀的凝固组织。辊式电磁搅拌器是达混利罗特莱克的专有技术，     

连铸用电磁搅拌技术

电磁搅拌能够有效地增加铸坯等轴晶率,减少铸坯中的夹杂物和中心偏析等缺陷,已经成为改善铸坯和成品质量的重要手段之一。回顾了电磁搅拌技术的发展,介绍了电磁搅拌的类型。根据安装位置不同,电磁搅拌分为结晶器、二冷区和凝固末端搅拌。每种电磁搅拌具有各自的特点和冶金效果,电磁搅拌参数影响电磁搅拌的冶金效果。选择合适的电磁搅拌器和电磁搅拌参数,能够提高电磁搅拌的冶金效果。     

板坯连铸机辊式电磁搅拌的应用实践

武钢第二炼钢厂在应用辊式电磁搅拌装置的过程中,对辊式电磁搅拌器的安装位置和搅拌参数进行多次试验与研究,确定电磁搅拌器的合适安装位置,并对搅拌工艺参数进行优化,使之达到较好的冶金效果.     

Φ380 mm 40Cr钢连铸圆坯结晶器电磁搅拌器电流参数优化

为研究Φ380 mm合金结构钢40Cr连铸圆坯生产过程中采用的结晶器电磁搅拌技术对铸坯质量的影响,对结晶器电磁搅拌器(M-EMS)进行磁感应强度检测,并研究电磁搅拌器磁场分布规律以及不同电流参数下对连铸大圆坯质量的影响。试验结果表明,结晶器电磁搅拌电流和频率分别为300 A、2.5 Hz时,Φ380 mm 40Cr钢连铸圆坯中心碳偏析指数可稳定控制在1.05以下。     

电磁搅拌对高碳钢铸坯质量的影响

通过现场应用试验考察了电磁搅拌对高碳钢65Mn铸坯质量的影响,结果表明：电磁搅拌采用同侧安装的效果要好于对面安装的效果;电磁搅拌的效果随着电流强度的增加而增大;相同条件下,连续搅拌的作用效果要好于交替搅拌的作用效果;高碳钢65Mn使用电磁搅拌优化工艺后,铸坯内部质量有了明显改善,等轴晶率提高了32%,中心偏析降低到C1.0。     

电磁搅拌和过热度对Q345钢铸坯内部质量的影响

以改善Q345钢连铸坯中心质量和组织为目的,进行了不同连铸工艺的对比试验。结果表明,与常规工艺相比,结合电磁搅拌的工艺可显著提高铸坯中心等轴晶率;仅降低钢水过热度虽然对降低铸坯中心偏析作用明显,但其提高铸坯中心等轴晶率的效果低于采用电磁搅拌的效果。     

电磁搅拌对包钢板坯等轴晶率的影响

文章主要对包钢宽厚板坯连铸机采用二冷区电磁搅拌后,不同电磁搅拌参数对板坯中心等轴晶率的影响进行了分析。生产实践表明:当连铸工艺相同时,随着搅拌电流、搅拌频率的增大,板坯的中心等轴晶率平均增加了20%。     

Effects of continuous casting process parameters on carbon segregation degree of 38CrMoAl steel big round billet

The effects of continuous casting process parameters (superheat degree, casting speed and F- EMS) on the carbon segregation of round billet with diameter 600mm of 38CrMoAl steel were investigated by industrial experiments and numerical simulations. The results show that the equiaxed crystal rate and solidification structure both affect the carbon segregation. When the superheat is low, shrinkage tends to occur, and the shrinkage is often accompanied by severe segregation. When the superheat is high, the equiaxed grain ratio is lower, carbon segregation is also severer, so the superheat degree is controlled at 30??. With the increasing of casting speed?? it can obviously spur the growth of columnar crystals and formation of central pipe; both columnar crystals and central pipe are the major cause of segregation, so the suitable casting speed is 0. 19m/min. Final electromagnetic stirring has the effect of uniform liquid steel composition and temperature, which increases the density of solidification structure, and reduces the central shrinkage hole, thereby reducing carbon segregation, but the electromagnetic stirring effect is greatly affected by the installation position. Based on comprehensive consideration of the production and quality in practical production, the suitable process parameters are established: the optimal superheat is 30??, casting speed is 0. 28m/min, the combination of electromagnetic stirring is M- EMS+S- EMS+F- EMS, and the corresponding electromagnetic stirring parameters are M- EMS of 101A/2Hz??S- EMS of 200A/8Hz??F- ME of 900A/8Hz. Under the above process conditions, it will be more reasonable for the F- EMS installation position to move 0. 4-0. 5m toward the meniscus.     

Effect of electromagnetic stirring on flow field in mold under submerged entry nozzle clogging

A physical model with mercury as analog was developed to investigate the influences of electromagnetic stirring( EMS) on flow field in slab continuous casting when the submerged entry nozzle( SEN) was clogged with different clogging rates( 0,10%,25%,and 50%). The flow field in mold under different EMS currents( 0,40 A,and 60 A) was measured by an ultrasonic Doppler velocimeter. The results proved that the flow field in the mold was a typical double roll structure under non-clogging SEN. As the SEN clogging rate increased,the flow field structure was transformed from a double roll to asymmetry flow. When the clogging rate reached 50%,the up circulation disappeared on the clogged side. The zone under the meniscus near the narrow face was a non-flowing area. EMS could correct bias flowcaused by SEN clogging and improve the symmetry of the flow field during SEN clogging.     

Study on Solidification Structure of Wheel Steel Round Billet Using FE‐CA Coupling Model

Solidification structure of wheel steel round billet during the continuous casting process was simulated using FE (Finite Element)–CA (Cellular Automaton) coupling model. Variation of thermo‐physical parameters during solidification was considered based on a thermodynamic database. Meanwhile effect of electromagnetic stirring (EMS) was reflected by increasing both the thermal conductivity and crystal formation rate in liquid phase. It was found that the cooling curves and solidification structure calculated by this model agreed well with that in experiments. Optimum casting temperature range was discussed based on the simulation results and actual conditions in plant. An optimized casting superheat will be no more than 25 °C in order to obtain at least 50% equiaxed crystal ratio, while the degree of segregation in the billet is less than 1.05 correspondingly.     

电磁搅拌技术在连铸上的应用

在连铸坯凝固过程中,由于冷却速度很快,造成铸坯凝固时柱状晶的发展,往往产生＂搭桥＂现象,导致铸坯内缩孔、偏析、疏松、夹杂物聚集等缺陷产生。为解决以上问题,电磁搅拌技术应运而生,采用电磁搅拌装置,有利于改善连铸坯的凝固组织,从而改善铸坯表面及内部质量。本文介绍了电磁搅拌的主要类型、设备组成及其应用效果。     

Performance of ANFIS Coupled with PSO in Manufacturing Superior Wear Resistant Aluminum Matrix Nano Composites

In this study, ANFIS was combined with PSO in order to optimize the parameters in pressure assisted semi solid processing of A360 aluminum matrix nano composites. ANFIS was utilized to calculate the objective function, which was later minimized using PSO. Combination of EMS semi solid processing and pressure assistance during solidification resulted in improvement of microstructural features and tribological properties. Globular grain structure was formed in the pressure assisted EMS parts. Tribological properties were investigated using pin on disk. It was noted that wear properties of EMS parts were benefited from the refinement of the primary α-Al phase and uniform distribution of the particles. EMS composites showed higher hardness than conventional cast parts, consequently there was a lower real area of contact and therefore lower wear rate. Moreover, hard dispersoid made the virgin alloy plastically constrained and improved their wear resistance.     

水口结构对连铸中低碳钢流场和温度场的影响

 为研究水口结构形状对连铸中低碳钢结晶器内流场和温度场分布的影响,采用有限容积法建立连铸圆坯三维数学模型,模拟了不同水口形状下圆铸坯的流场和温度场。结果表明,在水口浸入深度为80 mm、其他参数不变时,与直水口相比,旋流水口使钢水冲击深度降低,结晶器内涡流增强,弯月面温度和二冷区凝固率提高,且随着水口数量的增加,弯月面波高和结晶器出口温度降低;采用旋流水口并施加结晶器电磁搅拌(M EMS)时,结晶器中钢液温度升高,弯月面有卷渣行为,结晶器出口未形成凝固坯壳。在实际应用中,应避免同时使用M EMS和旋流水口,或使用旋流水口时采用低强度的M EMS。     

Prospect of energy management system for large steel enterprise

The energy management system(EMS),which acts as the heart of the energy management center of a steel enterprise,is a large computer system focused on the concentrative monitor and control of the production and utilization of energy.Although Chinese steel industry was well developed in the latest decade, so far the levels of the comprehensive energy consumption per ton steel among Chinese steel enterprises are remarkably distinct,and the average value of the comprehensive energy consumption per ton steel of them has still been much higher than the value of those in developed countries.This bad situation,in the opinion of the author,partially results from the poor ability for most Chinese steel enterprises to manage the production and utilization of energy.National policies associated to energy-saving and ejection-decreasing call for steel enterprises to build the EMS;and more and more steel enterprises themselves also desire to achieve EMS projects so that they can optimize their energy production and utilization.Baosteel,the largest and most advanced steel enterprise in China,has got plenty of experience in the EMS due to its incessant practice for more than 30 years in the design,construction,application,and revampment of its EMS.In the present article,the features of an advanced EMS is described and discussed based on the design practice of the EMS of Baosteel Zhanjiang Project.An advanced EMS should be an optimized and integrated system,which possesses of the characteristic of high managing efficiency,enough openness in expansion,friendly interfaces, and simple structure.Furthermore,it could support many-sided applications,e.g.,energy related data mineing,energy network combination and co-supply,application of geographic information technology,and other technical researched on energy-saving aspects.It is known that some energy-related indexes of Baosteel have stood on a high level better than those of some worldwide famous steel enterprises.Moreover,it goes without saying that the indexes of Baosteel Zhanjiang will be better than those of present Baosteel.Therefore, one can easily expect that the new EMS of Baosteel Zhanjiang will be much more advanced,which will be more helpful to fulfil systematiclly saving of energy,to elevate the efficiency of energy utilization,to lower the comprehensive energy consumption per ton steel.