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Influence of Billet Size on Flow,Solidification and Solute Transport in Continuous Casting

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Journal of Iron and Steel Research(International) 2003年第3期10卷 22-27页

作者： ZHANG Hong-wei WANG En-gang he ji-cheng Northeastern University

The dead load crown of hydraulic elastic bulging roll was discussed using the theory of elastically supported beam, and the dead load experiment was carried out. The theoretical calculation is consistent with the experimental result. The structure parameters for the thickness of roll sleeve, the length of the oil groove and the crown of roll were discussed. The fundamental principle of determining the parameters was put forward. The theoretical basis of the application of the hydraulic elastic bulging roll was established.

关键词： hydraulic elastic bulging roll bulging crown dead load

Estimation of the Aircraft CO_2 Emissions of China's Civil Aviation during 1960-2009

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Advances in Climate Change Research 2012年第2期3卷 99-105页

作者： he ji-cheng XU Yu-Qing Division of Environment and Resources Research Transport Planning and Research Institute Ministry of Transport Beijing 100028 China National Climate Center China Meteorological Administration Beijing 100081 China

Based on data collected by Chinese Civil Aviation Statistic Center, the annual CO 2 emissions of aircrafts during 1960-2009 were calculated, and the emission intensity and its dynamic characteristics were analyzed. The results show that the total CO 2 emissions of aircrafts in China increased from 120 × 10 3 t in 1960 to 41.44 × 10 6 t in 2009. The CO 2 emission intensity decreased from 2.9 kg (converted t km) 1 in 1960 to 0.96 kg (converted t km) 1 in 2009 at an average rate of 0.04 kg (converted t km) 1 per year. The average share of CO 2 emissions of aircrafts on the total CO 2 emissions from the sector of transportation, storage and post was 6.6% during 1980-2005, and 0.25% on the total emissions from fossil fuel combustion during 1971-2008.

关键词：二氧化碳排放量民航飞机中国民航碳排放强度平均增长率估计排放总量动态特性

Kinetics of Oxidation Reaction for Magnetite Pellets

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Journal of Iron and Steel Research(International) 2013年第9期20卷 16-20页

作者： LIANG Ru-quan YANG Shuo YAN Fu-sheng he ji-cheng Key Laboratory of National Education Ministry for Electromagnetic Process of Materials Northeastern University Research Institute Northeastern University

An experiment for the oxidation process of single magnetite pellet and theoretical analysis based on modi lied unreacted core shrinking （MUCS） model were carried out, and the controlling mechanisms of the initial and de veloping reactions were examined, respectively. From the study of the initial reaction, it was found that the chemical reaction of surface is the controlling step of the overall reaction when the temperature is up to about 750 K, while the mass transfer through the gaseous boundary layer dominates the reaction rate when the temperature is above 750 K. As the reaction developing within the pellet, the mass transfer through the produced layer becomes the controlling step. In addition, the effects of reaction conditions （such as oxygen concentration, temperature） on the fractional oxidation of magnetite pellet were determined.

关键词： magnetite pellet shaft furnace kinetics oxidation reaction controlling step

Research of Electromagnetic Field on Several Metallic Materials and Processing

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Journal of Iron and Steel Research(International) 2012年第S1期19卷 25-33页

作者： WANG En-gang he ji-cheng Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern University

The research activities in EPM for several metallic materials are classified in the application of different magnetic field.The following research is exhibited in this article,(1)Effect of magnetic field on solidification process of monotectic alloys;(2)Effect of high magnetic field on fabrication of high-strength and high-conductivity copper alloys;(3)Numerical simulation of magnetic field and fluid flow in continuous casting mold with vertical electromagnetic brake;(4)Research on solidification structure of superalloy with EMS;(5)Effects of static magnetic field on the behavior of meniscus in a mold under argon gas injection.

关键词： Electromagnetic field Metallic Materials Processing

Composition and partition of biomass in a smith fir (Abies georgei var.smithii) timberline forest on the Sergyemla Mountain,southeastern Tibetan Plateau

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Forestry Studies in China 2010年第3期12卷 131-136页

作者： he ji-cheng LUO Tian-xiang XU Yu-qing Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 R R. China Energy Saving Environmental Protection ＆ Occupational Safety and Health Research Institute China Academy of Railway Sciences Beijing 100081 P. R. China National Climate Center China Meteorological Administration Beijing 100081 E R. China

The southeastern Tibetan Plateau has the highest timberlines in the world and climate change affects this area to a considerable extent. Quantification of vegetation biomass in the forests at the timberline is essential for understanding carbon balance, forest structure and functional changes in the forests at timberlines. We describe biomass and its constituent components of a smith fir tim- berline forest occurring at an elevation of 4320 m on the Sergyemla Mountain in the southeastern Tibetan Plateau. The results show that, in the tree layer, the average diameter at breast height （DBH） was 35.6 cm, the density 251 trees per hectare with a total biomass of 309.9 t.ha 1. Of the total biomass, the tnmks accounted for 70.49%, branches for 9.09%, leaves for 5.57% and roots for 14.85%. The total biomass in the shrub layer was 77.9 t＇ha-~ of which the biomass of trunks, branches, leaves and roots accounted for 42.8, 14.9, 4.6 and 15.6 t.ha-1, respectively. The total biomass in the herb layer was 3.0 t.ha-1. The total vegetation biomass in the smith fir timberline forest was 390.9 t-ha-l, to which the tree layer contributed the most （79.3%）, followed by shrubs （19.9%） and herbs （0.8%）. We estimate that the smith fir forest stand at the timberline had a higher total biomass than other fir or spruce forest stands in the surrounding area.

关键词： biomass smith fir Sergyemla Mountain allometric equations

Modeling of Orientation and Alignment of Primary Al_3Ni Crystal in Al-Ni Alloy by Imposing a High Magnetic Field

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Journal of Iron and Steel Research(International) 2012年第S2期19卷 1095-1098页

作者： ZHANG Hong-wei jiANG Xing he ji-cheng Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern University

Regarding Al_3Ni crystal as a rigid ellipsoid,a model describing the orientation and alignment of a primary paramagnetic Al_3Ni crystal in Al- Ni alloy solidification under a high magnetic field is developed.The model is based on rigid body rotation dynamics model as well as the magnetic dipole model,respectively.It describes the rotational motion of a magnetic anisotropic crystal around its centroid and around one endpoint of its crystal axis.The orientation time and the orientation characteristics with the intensity of magnetic field,the aspect ratio of the crystal and the effective viscosity of the melt,as well as the crystal growth,are deeply discussed for single grain.Furthermore,the interaction between two crystals during the alignment in high magnetic field are analyzed based on the magnetic dipole model,in which the final state of the grain is dependent on the attractive interaction force between two neighboring grains and the magnetization force acting on each grain.The prediction shows fitness with the experimental and theoretical results in literature.

关键词： high magnetic field magnetocrystalline anisotropy rotation magnetic interaction

Numerical Simulation on Distribution of Stress in the Electromagnetic Soft-Contact Continuous Casting Mould

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Journal of Iron and Steel Research(International) 2012年第S1期19卷 175-178页

作者： KANG Li WANG En-gang he ji-cheng Material Institute Taiyuan University of Science and Technology The Key of Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern University

A two-dimensional axisymmetric finite element model for stress distribution of billet in electromagnetic soft-contact continuous casting mould was established by a two-way coupled method.The contact state between solidified shell and mould was described to simulate the thermal-mechanical behaviors in the soft-contact mould.And the effects of frequencies and currents on stress distribution of billet had been discussed and analyzed.The results show that the equivalent stress of initial solidification shell both at its outer and inner surface decreases but at the bottom the equivalent stress of two sides of shell both increases when the current intensity is 1600 A,and the frequency is 20 kHz,compared with the status of conventional continuous casting.

关键词： Electromagnetic field soft-contact stress elastic-plastic model numerical simulation

Application of MHD Phenomenon on Secondary Refining and Continuous Casting Process

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Journal of Iron and Steel Research(International) 2012年第S2期19卷 941-944页

作者： GENG Dian-qiao LEI Hong he ji-cheng Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern University

In present work,the application of Magneto Hydrodynamics(MHD)to control the flow of liquid steel during secondary refining and continuous casting has been discussed.A mathematical model was developed to predict the flow field under magnetic field in different metallurgical reactors.As examples,the effect of traveling magnetic filed in RH degasser has been discussed,and the effect of electromagnetic brake(EMBR)on flow field during continuous casting process has also been discussed.The numerical results show that when the EMBR is installed near the nozzle port,the intensity of impinging jet near the narrow face mold wall is reduced,the downward flow becomes weaker,and the lower recirculation zone becomes smaller.The circulation flow rate with traveling magnetic field imposed around the up snorkel in RH degasser is greater than that with magnetic field imposed around the down snorkel if the gas flow rate is less than the saturated value,but they are almost the same if the gas flow rate is greater than the saturated value.

关键词： magnetic field MHD RH flow field continuous casting EMBR

Effect of Cr on Steel Solidification Structure Under EMS

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Journal of Iron and Steel Research(International) 2012年第S1期19卷 394-399页

作者： CheN jin SU Zhi-jian Keiji Nakajima he ji-cheng Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern University Division of Applied Process Metallurgy Department of Materials Science and Engineering Royal Institute of Technology(KTH)SE-10044 StockholmSweden

Solidification experiments of Cr steel under linear EMS were conducted to investigate the columnar-to-equiaxed transition(CET).The results are compared with those in carbon steel to clarify effect of Cr content and EMS.The conclusions are as follow:The criterion for dendrite fragmentation under linear EMS is obtained and verified by previous paper,then is considered valid for Cr steel.Investigation is carried out on the relation between the superficial velocity in the bulk flow and critical solid fraction at the time of dendrite fragmentation(CET occurrence).The critical solid fraction is smaller in high Cr case.As a result,the CET occurrence is more difficult in this case.

关键词： Cr steel secondary arm spacing dendrite fragmentation CET solid fraction