材料期刊网

NUMERICAL STUDY ON 3-D FLUID FLOW WITHIN THE MOLTEN POOL DURING UNEQUAL DIAMETER TWIN ROLL STRIP CAST-ROLLING

S. W Ma , J.C , He and H.S. Di 1) School of Materials and Metallurgy , Northeastern University , Shenyang 110006 , China 2) The State Key Laboratory of Rolling and Automation , Northeastern University , Shenyang 110006 , China

金属学报(英文版)

In this paper three-dimensional flow field in the molten pool between unequal diameter twin rolls has been studied by BFC technology and SIMPLEC numerical method. From the computed flow pattern,the characteristic of molten steel flow has been discussed. The dynamics generated by the feeding flow and the motivation of counter-rotating twin rolls produces a recirculating flow field nearby the small roll due to the larger room and less resistant here and fluid flows along the roll surface tangential nearby large roll and extends to two side dams. There is faintly flow around the dams of molten pool

关键词: NNSCC , null , null , null , null

Key R&D activities for development of new types of wrought magnesium alloys in China

Transactions of Nonferrous Metals Society of China

Many researchers in China are actively engaged in the development of new types of wrought magnesium alloys with low cost or with high-performances and novel plastic processing technologies. The research activities are funded primarily through four government-supported programs: the Key Technologies R&D Program of China, the National Basic Research Program of China, the National High-tech R&D Program of China, and the National Natural Science Foundation of China. The key R&D activities for the development of new wrought magnesium alloys in China are reviewed, and typical properties of some new alloys are summarized. More attentions are paid to high-strength wrought magnesium alloys and high-plasticity wrought magnesium alloys. Some novel plastic processing technologies, emerging in recent years, which aim to control deformation texture and to improve plasticity and formability especially at room temperature, are also introduced.

关键词: wrought magnesium alloy;microstructure;properties;alloy designing;plastic deformation;research projects;y-zr alloys;mechanical-properties;mg-4y-4sm-0.5zr alloy;grain-refinement;rare-earth;microstructure;gd;phase;temperature;evolution

Laboratory of Solid State Microstructures(LSSMS)

材料科学技术（英文）

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SOLID-STATE AMORPHIZATION REACTIONS IN NI/TI MULTILAYER COMPOSITES PREPARED BY COLD-ROLLING

Journal of Materials Science

Solid state amorphizations in mechanically deformed Ni/Ti multilayer composites have been investigated by differential scanning calorimetry and X-ray diffraction. The growth of amorphous alloy in our Ni/Ti composites was facilitated by the large number of grain boundaries and relatively large degree of disorder induced in the metal layers by the cold rolling. The formation of different products of solid-state reaction in the Ni/Ti composites has bee,n elucidated in terms of magnetic and enthalpy analysis. It is thought that the solid state amorphization occurs first during heating, followed by the formation of intermetallic compounds through direct solid-state reaction of elemental nickel and titanium and by the crystallization of the amorphous alloy already formed by the solid state amorphization reaction. The values of the activation energy for interdiffusion and interdiffusion coefficient for the formation of amorphous alloy in the Ni/Ti composites have also been calculated.

关键词: diffusion couples;interdiffusion reactions;elemental composites;thin-films;ni/zr;ni;planar;binary;growth;alloys

Texture of Cold Rolled Strip of Fe-3Si Steel Produced by Thin Slab Casting and Rolling

LI Chang-sheng , YANG Hua , WANG Yan-fang , YU Yong-mei

钢铁研究学报(英文版)

The hot rolled strip of Fe-3Si steel was experimentally produced by thin slab casting and rolling (TSCR) process in the laboratory. The texture evolution rule was investigated during hot rolling and cold rolling. The texture distribution of cold rolled strips with four kinds of cold rolling reduction schedules was observed through X-ray diffraction method, and the orientation density variation of 1/16 layer, 1/8 layer, 1/4 layer, and 1/2 layer in thickness was analyzed. The cold rolled texture of steel A with four kinds of cold rolling reduction schedules was mainly composed of α and γ fibers. Cold rolling reduction ratio of 70% was more beneficial for obtaining more γ fibers. The γ fiber texture orientation density of {111}<011> and {111}<1 12> was the largest on the 1/8 layer and 1/4 layer and the least on the 1/16 layer and 1/2 layer for steel B. The texture orientation density of {001}-{223}<110> in the α fibers for steel C was increased, but the texture orientation density of {332}-{110}<110> was low.

关键词: silicon steel , texture , hot rolling , cold rolling , thin slab , continuous casting , direct rolling

Influence of Pass Parameters on Retained Mandrel Rolling Process

YU Hui , DU Feng-shan , XU Zhi-qiang

钢铁研究学报(英文版)

Roller pass is one of the key factors affecting the product quality in the retained mandrel rolling process. The metal flow condition of rolling deformation area was researched using the FEA (finite element analysis) software Marc. The influences of the pass bottom radius, the sidewall radius, the sidewall angle, the roller shoulder fillet radius, as well as the roller gap on the rolling process under the conditions of different friction were discussed. Based on these results, the changes of the workpiece exit width, the mandrel axial force, the rolling force, and the rolling torque associated with various parameters were determined, which would provide the basis for designing the pass and determining the rolling condition reasonably.

关键词: finite element analysis

Further development of NdFeB magnet industry in China

Yang LUO

材料科学技术（英文）

Due to continued growth in key markets, a broadening of application base and performance improvements, the market demands of NdFeB magnet increased steadily in 1998, and the global output of sintered NdFeB magnet exceeded 10,000 t, in spite of the economic recession in Asia. In 1998 China produced 3,850 t sintered NdFeB block magnet, with an annual growth rate of +22% over the output in 1997.

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Properties of ground state in the spin-3/2 transverse Ising model with crystal field

Physica Status Solidi B-Basic Research

The properties of the ground state in spin-3/2 transverse Ising model with the presence of a crystal field are studied by using the effective-field theory with correlations. The longitudinal and transverse magnetizations and the phase diagram and internal energy in the ground state are given numerically for the honeycomb lattice (z = 3).

关键词: fermion compound ybbipt;magnetic-properties;phase-transition;square;lattice;mixed spin-1;system

ELECTRONIC-STRUCTURE AND EQUATION OF STATE OF TIB2

Journal of Physics-Condensed Matter

The electronic structure of TiB2 has been calculated using the self-consistent LMTO-ASA method. Our results have been compared with experimental and other theoretical work. We find that the pseudo-gap at the Fermi level is the competing effect of Ti 3d resonance and strong hybridization between Ti 3d and B 2p states. The bonding nature of TiB2 is discussed. We have carried out calculations of the equation of state (EOS) Of TiB2; it is found that our first-principles calculated results support the universal model of EOS proposed by Vinet et al. The room-temperature isotherm is also plotted.

关键词: binding-energy relation;borides;solids;chemisorption;metals

Change in Carbon Dioxide (CO2) Emissions From Energy Use in China′s Iron and Steel Industry

SUN Wenqiang , CAI Jiuju , MAO Hujun , GUAN Duojiao

钢铁研究学报(英文版)

As the largest energy consuming manufacturing sector and one of the most important sources of carbon dioxide (CO2) emissions, the China′s iron and steel industry has paid attention to the study of changing trend and influencing factors of CO2 emissions from energy use. The logarithmic mean Divisia index (LMDI) technique is used to decompose total change in CO2 emissions into four factors: emission factor effect, energy structure effect, energy consumption effect, and steel production effect. The results show that the steel production effect is the major factor which is responsible for the rise in CO2 emissions; whereas the energy consumption effect contributes most to the reduction in CO2 emissions. And the emission factor effect makes a weak negative contribution to the increase of CO2 emissions. To find out the detailed relationship between change in energy consumption or steel production and change in CO2 emissions, the correlation equations are also proposed.

关键词: CO2 emissions , energy use , LMDI technique , steel production , energy consumption