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Mathematic Model of SEN Clogging During Continuous Casting of Steel

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Journal of Iron and Steel Research International 2010年第8期17卷 6-9页

作者： WU Su-zhou zhang jiong-ming LI Zhi-zheng School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

The SEN clogging is a serious problem for continuous casting operation and steel *** kinetics mathematic model of SEN clogging during steel continuous casting is *** fluid flow and inclusions motion are calculated by means of mathematic *** of diameters of inclusions,roughness of nozzle,diameter of nozzle and casting speed on the entrapment probability are calculated and *** result shows that inclusions are more easily to attach to the nozzle by the following condition：smaller inclusion size,larger roughness of the wall and the smaller bulk velocity in the nozzle.

关键词： nozzle clogging mathematic model inclusion motion

Simulation of solidification microstructure of Fe-6.5%Si alloy using cellular automaton-finite element method

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Journal of Central South University 2016年第9期23卷 2156-2164页

作者： SONG Wei zhang jiong-ming WANG Shtm-xi WANG Bo HAN Li-lei State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing 100083 China

3D microstructures of Fe–6.5%Si(mass fraction) alloys prepared under different cooling conditions were simulated via finite element-cellular automaton(CAFE) method. The simulated results were compared to experimental results and found to be in accordance. Variations in the temperature field and solid-liquid region, which plays important roles in determining solidification structures, were also examined under various cooling conditions. The proposed model was utilized to determine the effects of Gaussian distribution parameters to find that the lower the mean undercooling, the higher the equiaxed crystal zone ratio; also, the larger the maximum nucleation density, the smaller the grain size. The influence of superheat on solidification structure and columnar to equiaxed transition(CET) in the cast ingot was also investigated to find that decrease in superheat from 52 K to 20 K causes the equiaxed crystal zone ratio to increase from 58.13% to 65.6%, the mean gain radius to decrease from 2.102 mm to 1.871 mm, and the CET to occur ahead of schedule. To this effect, low superheat casting is beneficial to obtain finer equiaxed gains and higher equiaxed dendrite zone ratio in Fe–6.5%Si alloy cast ingots.

关键词： finite element-cellular automaton Fe-6.5%Si alloy microstructure temperature field Gaussian distribution parameters

Control of Macrosegregation Behavior by Applying Final Electromagnetic Stirring for Continuously Cast High Carbon Steel Billet

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Journal of Iron and Steel Research International 2013年第11期20卷 13-20页

作者： XIAO Chao zhang jiong-ming LUO Yan-zhao WEI Xiao-dong WU Lian WANG Shun-xi State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

Solidification behavior of continuously cast high carbon steel billets was investigated with an objective of producing high quality billets by determining the optimum final electromagnetic stirring （F-EMS） parameters. Char- acteristics of centerline segregation were analyzed for lots of billet samples collected from the plant through obtaining the carbon concentrations of drill chips, which were correlated with the operating parameters of the caster and stir- rers, but a problem occurred that segregation control results of trial billets with the same casting and stirring param- eters often have drastic fluctuations. An attempt was made to find out the induced reasons of this problem by meas uring the electromagnetic torque, analyzing the secondary dendrite arm spacing （SDAS） and the corresponding cool- ing rate of the typical specimens, and observing the longitudinal profile of etched billet samples. Then a simple dy- namic secondary cooling model was developed based on the solidified shell thickness control mode, by which the maximum carbon segregation index was reduced effectively, and thus the segregation fluctuation problem was basi- cally solved. Finally, the most favourable stirring parameters were determined as the casting speed of 1.65 m/rain, the liquid core thickness of 40 mm, stirring current of 360 A and frequency of 12 Hz.

关键词： F-EMS carbon segregation index SDAS cooling rate stirring parameter

In Situ Observation of Solidification Process of AISI 304 Austenitic Stainless Steel

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Journal of Iron and Steel Research International 2008年第6期15卷 78-82页

作者： HUANG Fu-xiang WANG Xin-hua zhang jiong-ming JI Chen-xi FANG Yuan YU Yan Metallurgical and Ecological Engineering School University of Science and Technology Beijing Beijing 100083 China Advanced Technology Institute of Technology Center Baoshan Iron and Steel Co Ltd Shanghai 201900 China

The solidification process of AISI 304 stainless steel during cooling at a rate of 0.05 K/s has been observed in situ using a confocal scanning laser microscope （CSLM）. The results show that the 8 phase appeared first in liquid steel, as the temperature decreased, the γ phase precipitated prior at δ-grain boundary at 1452. 2 ℃, the liquid steel disappeared at 1 431.3 ℃, and then the γ phase precipitated on the δ ferrite. Based on the Scheil-Gulliver solidification model, the solidification processes of AISI 304 stainless steel are simulated using the Scheil model in Thermo Calc, and the simulation results agree well with the results observed in the experiment.

关键词： stainless steel confocal scanning laser microscope strip casting Thermo Calc

Study on Solidification Microstructure of Slab by Numerical Simulation

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Journal of Iron and Steel Research International 2011年第S2期18卷 371-376页

作者： LIU Zhi-ming, zhang jiong-ming, LUO Yan-zhao, WU Lian (School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China) Univ Sci & Technol Beijing Sch Met & Ecol Engn Beijing 100083 Peoples R China

The solidification structure was simulated by the commercial software CALCOSOFT under the real cooling condition during the continuous casting processes in this paper. The cellular automation-finite element model (CA-FE) was applied to simulate the microstructure of the slab, and the results were compared with the actual macrostructure. The results of microstructure simulated were in good agreement with that detected in the slabs. In addition, the solidification structure under different secondary cooling intensity was simulated. The results show that when specific water flows increase, the average grain surface area reduces, and columnar grains have the tendency to be longer.

关键词： numerical simulation continuous casting solidification structure

Quick-scanning X-ray absorption fine structure beamline at SSRF

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Nuclear Science and Techniques 2024年第6期35卷 1-13页

作者： Yu Chen Qian Gao Zheng Jiang jiong Li Shuo zhang Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China

The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described ***11B is a bending-magnet beamline dedicated to conventional and millisecond-scale quick-scanning X-ray absorption fine *** is equipped with a cylindrical collimating mirror,a double-crystal monochromator comprising Si(111)and Si(311),a channel-cut quick-scanning Si(111)monochromator,a toroidal focusing mirror,and a high harmonics rejection *** can provide 5-30 keV of X-rays with a photon flux of~5×10^(11)photons/s and an energy resolution of~1.31×10^(-4)at 10 *** performance of the beamline can satisfy the demands of users in the fields of catalysis,materials,and environmental *** paper presents an overview of the beamline design and a detailed description of its performance and capabilities.

关键词： Bending magnet beamline X-ray absorption fine structure Quick-scanning XAFS In situ Synchrotron radiation

Numerical Simulation and Applications of F-EMS for High Carbon Steel Billet

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Journal of Iron and Steel Research International 2011年第S2期18卷 268-274页

作者： WEI Xiao-dong, zhang jiong-ming, XIAO Chao, HU Zhao-fan, YUAN Yang-yang (School of Metallurgical and Ecological Engineering University of Science and Technology Beijing, Beijing 100083, China) Univ Sci & Technol Beijing Sch Met & Ecol Engn Beijing 100083 Peoples R China

The distribution of electromagnetic fields and electromagnetic force of F-EMS were simulated by ANSYS12.0 software. The magnetic induction intensity and electromagnetic force of billet with various stirring parameters were cal- culated, then the relationship between the magnetic induction intensity and electromagnetic force was calculated. The results showed that the electromagnetic force is not positive with the magnetic induction intensity. Depending on the com- bination of the practical production, the central segregation of high carbon steel SWRH77B is improved effectively under the best stirring parameter that the current is 360A and the frequency is 12Hz.

关键词： billet numerical simulation magnetic induction intensity electromagnetic force segregation

An electron-transfer[Fe_(2)Co_(2)]square complex exhibiting unprecedented wide room-temperature hysteresis

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Science China Chemistry 2024年第4期67卷 1198-1207页

作者： Xin-Hua Zhao Yi-Fei Deng Jia-Tao Chen jiong Yang Yuan-Zhu zhang Department of Chemistry Southern University of Science and Technology(SUSTech)Shenzhen 518055China

Switchable molecules with magnetic bistability that can function at standard conditions are highly desirable from the perspective of practical *** the last decade,significant progress has been made in modulating thermally induced electrontransfer-coupled spin transition(ETCST)events between diamagnetic{Fe_(LS)^(Ⅱ)(μ-CN)Co_(LS)^(Ⅲ)}and paramagnetic{Fe_(LS)^(Ⅲ)(μ-CN)-Co_(HS)^(Ⅱ)}electron configurations(named LS and HS,respectively,for short)within the Fe/Co mixed-valence cyanometallate ***,we prepared a novel[Fe_(2)Co_(2)]square complex[(pzTp)Fe(CN)_(3)Co(bnbpen)]_(2)[NO_(3)]_(2)·4CH_(3)OH·2.5H_(2)O(1·Solv)and its desolvated phase[(pzTp)Fe(CN)_(3)Co(bnbpen)]_(2)[NO_(3)]_(2)(1),obtained via single-crystal-to-single-crystal(SCSC)*** 1·Solv remaining in the diamagnetic state below room temperature exhibits an irreversible ETCST behavior accompanied by desolvation upon ***,complex 1 displays an unprecedented rate-dependent ETCST behaviour involving with two diamagnetic LS states(a dynamically favoured LS1 state and a thermodynamically favoured LS2state),between which a net one-way transition from LS1 to LS2 is accessible likely via a structural phase transition(SPT)above255 ***,two well separated transition channels(HS?LS1 at around 255 K and HS←→LS2 in the temperature range of 317-350 K)are achieved according to either fast(>20 K/min)or slow rate(<1 K/min),*** a moderate rate of 3 K/min,complex 1 shows a wide hysteresis of 66 K centered at 328 K,the largest yet reported for discrete Fe/Co cyanometallate *** 1 represents the first ETCST example coupled with dynamic SPT,providing a new strategy for manipulating bistability within this fascinating cyanometallate family.

关键词： switchable molecules cyanometallate complexes electron transfer hysteresis structural phase transition

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宽板坯连铸结晶器内氩气分布的水模型

钢铁研究学报 2008年第10期20卷 17-20页

作者：陈阳张炯明北京科技大学冶金与生态工程学院北京100083

针对塞棒、上水口吹氩时,吹入的氩气有多少进入到结晶器钢水内和氩气在结晶器断面上如何分布的问题,采用1:1水模型,重点研究了吹气量、吹气方式、拉速、浸入式水口倾角等工艺参数对不同宽度结晶器内气体分布状况的影响。结果表明,吹气... 详细信息

针对塞棒、上水口吹氩时,吹入的氩气有多少进入到结晶器钢水内和氩气在结晶器断面上如何分布的问题,采用1:1水模型,重点研究了吹气量、吹气方式、拉速、浸入式水口倾角等工艺参数对不同宽度结晶器内气体分布状况的影响。结果表明,吹气量和吹气方式对结晶器内气体分布几乎没有影响,而拉速和水口倾角基本上就决定了宽度方向上的气体分布状况。小的结晶器断面宽度、小的水口倾角、高拉速时窄面附近含气比例更高,氩气泡更易被凝固坯壳所捕捉而使铸坯产生气泡缺陷。

关键词：宽板坯连铸氩气分布水模型浸入式水口