检索结果-南通市图书馆

Two-dimensional simulation on the rolling process of semi-solid 60Si2Mn by finite element method

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2002年第4期9卷 273-276页

作者： Renbo Song, Yonglin Kang, Xueping Ren, Hongbo Dong, and Jiwen WangMaterials science and Engineering school, university of science and technology beijing, beijing 100083, china Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The effect of various process variables on the law of metal flow for semi-solid rolling 60Si2Mn was studied by finite element method. Semi-solid 60Si2Mn can be described as compressible rigid visco-plastic porous material saturated with liquid. In terms of ther-mo-mechanical coupling condition, the distributions of stress, velocity and temperature were studied using software MARC. The simulation results show that the rigid visco-plastic model can accurately describe the semi-solid 60Si2Mn rolling process. The great deformation can achieve completely in view of low flow stress of semi-solid slurry.

关键词： finite-element analysis semi-solid thermo-mechanical coupling compressible rigid visco-plastic model rolling

A Fuzzy Model for Evaluating the Mining Condition of Underground Coal Mines

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第4期13卷 242-245页

作者： Zhongrue Li Shaowen Zhang(Resources Engineering school, university of science and technology beijing, Beding 100083, china) Resources Engineering school University of Science and Technology Beijing Beijing 100083 China

In mining industries no mines are identical and each mine has its own unique set of mining conditions. In order to study thecondition of mines for efficiency, safety and economy reasons, a fuzzy model is presented based on fuzzy evaluation. Relevant data fromfive mines were collected and the model was used to evaluate the mining condition of these mines. The evaluation results are in conformity with the real situation.

关键词： fuzzy model mining condition coal mine

NON-EQUILIBRIUM SEGREGATION OF Si ON Al-0.35 wt-% Si ALLOY SURFACE

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 98-101页

作者： CHEN Niug YU Zongsen university of science and technology beijing,beijing,china professor,Department of Materials Physics,university of science and technology beijing,beijing 100083,china beijing Univ of science and Technology Beijing China

Si segregation was observed in the vacancy condensation pits,formed by supersaturated vacancies beneath the oxidation layer of Al-0.35wt-％Si alloy,by optical microscopy,X- ray photoelectron spectroscopy and microhard... 详细信息

关键词： non-equilibrium segregation vacancy AI-Si alloy surface Si

Semi-solid slurry preparation and rolling of 1Cr18Ni9Ti stainless steel

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2003年第6期10卷 35-39页

作者： Weimin Mao, Aimin Zhao, Dong Yun, Leping Zhang, and Xueyou ZhongMaterials science and Engineering school, university of science and technology beijing, beijing 100083, china Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The preparation and rolling of the semi-solid slurry 1Cr18Ni9Ti stainlesssteel were researched. The experimental results show that when stirred for 2-3 min under the giventest condition, the semi-solid slurry with about 50 percent-60 percent (volume fraction) solid andthe spherical primary austenitic grains in the size of 100-200 mu m can be obtained, and it is easyto be discharged from the bottom little hole of the stirring chamber. The semi-solid slurry of1Cr18Ni9Ti stainless steel can be rolled into the given plate successfully. However, the solid phaseand liquid phase are easily separated in the rolling process, so that the solid primary austeniticgrains are concentrated in the center and the liquid phase is near the edge of the rolled plate. Thestrengths of the plate rolled in the semi-solid state are higher than that of the traditionallyrepeated hot-rolled plate of 1Cr18Ni9Ti stainless steel.

关键词： 1Cr18Ni9Ti semi-solid electromagnetic stirring rolling

Anisotropic characteristic in HDDR Nd_(13)Fe_(80)B_7

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2003年第3期10卷 26-29页

作者： Jingzhi Han, Aizhi Sun, Yaofu Xiao, Xubo Liu, and Run WangMaterials science and Engineering school, university of science and technology beijing, beijing 100083, china Materials science and Engineering school University of Science and Technology Beijing Beijing 100083 China

The function of disproportionation and desorption stages ofhydrogenation-disproportionation-desorption-recombination (HDDR) process in the formation ofmagnetic anisotropy was studied. The results showed that degree of anisotropy (DOA) ofNd_(13)Fe_(80)B_7 induced by appropriate HDDR process is comparable with that ofNd_(13)Fe_(80-x)B_7M_x (M=Co, Zr or Ga), however, the moderate coercive force of Nd_(13)Fe_(80)B_7magnetic powder led to an undesirable (BH)_(max) of 104 kJ/m^3 in bonded magnet. Experimentsdemonstrated that a relatively short disproportionation time, combined with a high desorptiontemperature and slow desorption rate, during HDDR process is beneficial to anisotropy attainment,but HDDR Nd_(13)Fe_(80)B_7 magnetic powder becomes isotropic if the disproportionation time islonger than a certain period. This phenomenon strongly indicated that the origin of anisotropy inNdFeB-type HDDR material is contributed by disproportionation stage. XRD (X-ray Diffraction)analysis and TEM (Transmission Electron Microscope) observation told that no other phase exceptNdH_2, alpha-Fe and Fe_2B has been found in the disproportionation step. The formation of HDDRNd_(13)Fe_(80)B_7 anisotropy might be related to the early lamella disproportionation structure.

关键词： HDDR anisotropy isotropy NdFeB

Analysis on Microstructure and Misorientation of Ultrathin Hot Strip of Low Carbon Steel Produced by Compact Strip Production

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & technology 2002年第6期18卷 501-503页

作者： Hao YU, Yonglin KANG and Jie FUschool of Materials science and Engineering, university of science and technology beijing, beijing 100083, china Sch. of Mat. Sci. and Eng. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The microstructure and misorientation of ultrathin hot strip were analyzed by CSP technology using electron back scattered diffraction (EBSD) method and Autoforge finite element program. The experimental results showed that the finishing hot rolling microstructures were the mixture of recrystallized and deformed austenite. After phase transformation, ferrite grains embody substructures and dislocations, leading to the high strength and relatively low elongation rate of the ultrathin hot strip. The FEM simulation of strain mode and distribution in deformation area has been fulfilled. The simulation results are in good agreement with the theoretical analysis and experimental results.

关键词： CSP Electron back scattered diffraction, Texture, Finite element method

Experimental Study of Fluid Flow in Thin Slab Continuous Caster Mould with Water-Model

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 15-19页

作者： Yanping Bao Jianqiang Zhu Naiyuan Tian Baomei Xu(Metallurgy school, university of science and technology beijing, beijing 100083, china) Metallurgy school University of Science and Technology Beijing Beijing 100083 China

Model study is an efficient method for optimizing the siructure of the mould and the submerged entry nozzle (SEN). Based on the similarity criteria, a full-scale water model has been established in accordance with the mould of thin-slab caster of the CSP (Compact Strip Production) operation. The effects of SEN structure including outlet area, outflow angle, nozzle width, thick-ness and immersion depth have been studied under high speed casting by measuring the amplitude and the impetus of top waves. By the orthogonal experiment design, not only the influence of the faCtors was estimated, but also the optimum work condition was judged. The rules of the fluid flow phenomena were summarized. The principle for choosing a reasonable structure of SEN was discussed.

关键词： thin-slab casting mould submerged entry nozzle (SEN) water-model

Study on Process Parameters of Vacuum Differential Pressure Casting

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2011年第S3期40卷 237-240页

作者： You Long, Wang Zidong university of science and technology beijing, beijing 100083, china Univ Sci & Technol beijing Sch Mat & Engineer Beijing 100083 Peoples R China

Vacuum differential pressure casting has advantages of smelting in vacuum, filling steadily, solidifying under high pressure. Process parameters of filling and solidification are important to the final castings’ forming properties, the parameters include vacuum degree, gas flow, filling velocity, filling pressure, rising pressure velocity, holding pressure and keeping pressure time. By casting copper alloy impeller, we calculated and deduced the gas flow, filling velocity, filling pressure, rising pressure velocity, holding pressure, and measured the keeping pressure time during experiment. Ultimately we convinced these parameters through experiment and successfully produced the impeller.

关键词： vacuum differential pressure casting copper alloy process parameters

A chaos genetic algorithm for optimizing an artificial neural network of predicting silicon content in hot metal

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2003年第2期10卷 68-71页

作者： Deling Zheng, Ruixin Liang, Ying Zhou, and Ying WangInformation Engineering school, university of science and technology beijing, beijing 100083, china Information Engineering school University of Science and Technology Beijing Beijing 100083 China

A genetic algorithm based on the nested intervals chaos search (NICGA) hasbeen given. Because the nested intervals chaos search is introduced into the NICGA to initialize thepopulation and to lead the evolution of the population, the NICGA has the advantages of decreasingthe population size, enhancing the local search ability, and improving the computational efficiencyand optimization precision. In a multi4ayer feed forward neural network model for predicting thesilicon content in hot metal, the NICGA was used to optimize the connection weights and thresholdvalues of the neural network to improve the prediction precision. The application results show thatthe precision of predicting the silicon content has been increased.

关键词： blast furnace optimization chaos genetic algorithm neural network silicon content prediction