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Activity model and its application in CaO-FeO-SiO_2-MoO_3 quarternary system

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Journal of University of Science and Technology Beijing 2004年第5期11卷 406-410页

作者： PeiminGuo ZhengbangLi GongwenLin centralironandsteelresearchinstitute Beijing100081China

The activity model of CaO-FeO-SiO_2-MoO_3 quarternary system was establishedaccording to the coexistence theory of slag structure and the reduction thermodynamics of molybdenumoxide was discussed by applying this model. The activities of SiO_2 and MoO_3 decrease, while thatof CaO increases with increasing the basicity of slag. Among SiC, [C] and [Si] reactants, thereducing capability of SiC is the strongest, while that of [C] is the poorest at a high temperature(about 1873 K). It is advantageous to increase the yield of molybdenum by increasing the content of[Si] or [C]. Controlling of basicity of slag can prevent the oxidation loss of molybdenum.

关键词： activity model molybdenum oxide thermodynamics direct reduction

Microstructure of NdFeB Strip Casting Flake

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Journal of Iron and Steel Research(International) 2005年第3期12卷 60-62页

作者： LIBo GUOBing-lin WANGDong-ling LIUTao LIUWen-chang YUXiao-jun centralironandsteelresearchinstitute Beijing100081China

The microstructures of NdFeB conventional ingot and strip casting (SC) flake were studied by BSE and energy spectra. The non-equilibrium state of the microstructure of SC flakes was discussed. By observing the change of microstructure of SC flakes after annealing at 700 ℃, 800 ℃ and 900 ℃, the characteristics of SC flakes were investigated further. The influence of the characteristic on magnetic property was analyzed.

关键词： microstructure NdFeB magnet strip casting annealing

Mechanical Properties and Friction/Wear Behavior of Copper Alloyed Powder Composites

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Journal of Iron and Steel Research(International) 2005年第4期12卷 50-53,59页

作者： DENGChen-hong CHENGuang-zhi GEQi-lu centralironandsteelresearchinstitute Beijing100081China

Copper alloyed powder composites containing nanoparticles were developed by hot pressing. Effects of nanoscale activated sintering aid and fine ceramic particles Al_2O_3 on hardness, working quality, and behaviors of friction and wear of the composites have been studied, compared with the composites including microscale activated sintering aid and microscale ceramic particles. The microstructures of the samples were analyzed by SEM. The results show that the materials with nanoscale sintering aid and fine ceramic particles have betuer mechanical properties and abrasive resistance than the materials with microscale activated sintering aid and microceramic particles. Moreover, element mutual transfer occurs between samples (strip) and abrasive wheel (ring).

关键词： nanoparticle activated sintering aid ceramic particle tribology

Giant stress—Impedance Effect in Amorphous and High—Current—Density Electropulsing Annealed Fe73.5Cu1Nb3Si13.5B9 Ribbons

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Chinese Physics Letters 2002年第7期19卷 1000-1001页

作者：李德仁卢志超等 NationalAmorphousandnanocrystallineAlloyEngineeringResearchCenter CentralIronandSteelResearchInstituteBeijing100081 NationalAmorphousandnanocrystallineAlloyEngineeringResearchCenter CentralIronandSte

The stress-impedance (SI) effect has been observed in as-cast and high-current-density electropulsing annealed Fe73.5Cu1- Nb3Si13.5B9 ribbons. Large SI ratios of -35% and 25% have been obtained in high-current-density electropulsing annealed samples but not in as-cast samples. The SI effect changes drastically with the density of the annealing current and the longitudinally applied stress during the annealing process. The effective permeability has been shown to be responsible for the SI effect.

关键词： Annealing

Dependence of Magnetic Properties and Microstructure of Ni_(81)Fe_(19) Film on Base Vacuum and Sputtering Pressure

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Journal of University of Science and Technology Beijing 2002年第1期9卷 45-47页

作者： HongchenZhao HongSi 等 MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijing100083China centralironandsteelresearchinstitute Beijing100081China

The Ni_81Fe_19 / Ta films with different NiFe thickness were prepared atdifferent base vacuums and sputtering pressures. The results of magnetic measurement and atomicforce microscope (AFM) showed that the films prepared at higher base vacuum and lower sputteringpressure had larger DELTAR/R. The reason should be that higher base vacuum and lower sputteringpressure introduce larger grainsize and lower surface roughness, which will weaken the scattering ofelectrons, reduce the resistance R, and increase DELTAR/R.

关键词： NiFe film anisotropic magnetoresistance surface roughness grain-size

EFFECT OF Fe_2O_3 ON WELDING TECHNOLOGY AND MECHANICAL PROPERTIES OF WELD METAL DEPOSITED BY SELF-SHIELDED FLUX CORED WIRE

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Chinese Journal of Mechanical Engineering 2005年第1期18卷 55-57页

作者： YuPing PanChuan XueJin LiZhengbang DepartmentofWeldingResearch CentralIronandSteelResearchInstituteBeijing100081China SchoolofMaterialsScienceandEngineering Xi＇anjiaotongUniversityXi＇an710049China DepartmentofMetallurgicalTechnology CentralIronandSteelResearchInstituteBeijing100081China

Five experimental self-shielded flux cored wires are fabricated withdifferent amount of Fe_2O_3 in the flux. The effect of Fe_2O_3 on welding technology and mechanicalproperties of weld metals deposited by these wires are studied. The results show that with theincrease of Fe_2O_3 in the mix, the melting point of the pretreated mix is increased. LiBaF_3 andBaFe_(12)O_(19), which are very low in inherent moisture, are formed after the pretreatment. Themechanical properties are evaluated to the weld metals. The low temperature notch toughness of theweld metals is increased linearly with the Fe_2O_3 content in the flux due to the balance betweenFe_2O_3 and residual Al in the weld metal. The optimum Fe_2O_3 content in flux is 2.5 percent approx3.5 percent.

关键词： Self-shielded flux arc welding Fe_2O_3 Welding technology Mechanicalproperties

Large magnetic-field-induced strains in rare earth polycrystalline Ni-Mn-Ga

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Rare Metals 2004年第3期23卷 241-245页

作者： ZHAOZengqi WUShuangxia WANGFangshu WANGQiang JIANGLiping WANGXinlin BaotouResearchInstituteofRareEarth Baotou014010China DepartmentofFunctionalMaterials CentralIronandSteelResearchInstituteBeijing100081China

The magnetic-field-induced strains (MFIS) of polycrystallineNi_(50)Mn_(29)Ga_(21) alloys containing Tb were studied. A large MFIS of -1.10% was obtained undercompressi ve prestress conditions. The addition of Tb can fine the crystal grains, enhance thebending strength obviously, and make MFIS increase further, indicating that a moderate amount of Tbdoes not hinder twin boundary motion and it conversely makes the material more practical.

关键词： metal materials magnetic-field-induced strain rare earths Ni-Mn-Ga alloy

Three Dimension Monte Carlo Simulation of Austenite Grain Growth in CGHAZ of an Ultrafine Grain Steel

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Journal of Materials Science & Technology 2003年第4期19卷 309-312页

作者： DongCHEN YongpingLEI XiaoyanLI YaowuSHI ZhilingTIAN SclloolofMaterialsScienceandEngineering BeijingPolytechnicUniversityBeijing100022China centralironandsteelresearchinstitute Beijing100081China

In the present research, the Monte Carlo technique was used to simulate the grain in the heat-affected zone (HAZ) of an ultrafine grain steel. An experimental data based (EBD) model proposed by Gao was used to establish the relation between tMCS and real time temperature kinetics in our simulation. The simulations give out the evolution of grain structure and grain size distribution in the HAZ of the ultrafine grain steel. A Microsoft Window based on computer program for the simulation of grain growth in the HAZ of weldment in three dimensions has been developed using the Monte Carlo technique. For the system, inputting the temperature field data and material properties, the evolution of grain structure, both image of simulated grain structure and numerical data reflecting the grain size distribution can be produced by the program. The system was applied to the ultrafine grain steel welding, and the simulated results show that the ultrafine grain steel has a large tendency of grain growth.

关键词： Ultra-fine grain steel HAZ Monte Carlo simulation

Delayed Fracture Behavior of CrMo-Type High Strength Steel Containing Titanium

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Journal of Iron and Steel Research(International) 2005年第1期12卷 43-49页

作者： HUIWei-jun DONGHan WENGYu-qing WANGMao-qiu CHENSi-lian SHIJie centralironandsteelresearchinstitute Beijing100081China ChineseSocietyforMetals Beijing100711China

The delayed fracture behaviors of CrMo-type high strength steels containing different amount of titanium(0to 0.10%)were studied.The steels were quenched at 880℃ and tempered from 400℃ to 650℃,and a wide range of tensile strength was obtained.The sustained load tensile test was carried out by using notched tensile specimens in Walpole solution.The experimental results showed that with higher strength,the Ti-microalloyed steels show higher resistance to delayed fracture compared with non-microalloyed steel due to titanium beneficial role and microstructure changes.The undissolved TiC is uniformly distributed as strong hydrogen traps,retarding or preventing the diffusion and accumulation of hydrogen to lower-interaction energy sites,such as prior austenite and martensite lath boundaries in stress concentration area.Meanwhile,the grain refining effect of titanium is also an important factor to improve the delayed fracture resistance of Ti-microalloyed steels.The characteristics of delayed fracture remain nearly the same with titanium addition.

关键词： titanium delayed fracture high strength steel CrMo steel