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Temperature distribution in the tool-chip-workpiece system during the orthogonal cutting process

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International Journal of Minerals,Metallurgy and Materials 1997年第3期11卷 30-34页

作者： ZHENG Chun GU Tong (Department of Mechanical engineering, McMaster university, Canada) (Applied science {3., university of science and Technology beijing, beijing 100083. china) McMaster Univ Canada

The temperature distribution in the tool, chip and workpiece was studied during the orthogonal cuttingprocess Under several different cutting conditions. The temperature distribution is calculated by the finite differencemethod. and the variation of the material properties with temperature was taken was taken into account The results obtained arecoincident with both previous published results and experimental measurements.

关键词： temperature distribution orthogonal cutting FDM tool-chip-workpiece system

Preparation and characterization of nano-crystalline diamond films on glass substrate

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Journal of university of science and Technology beijing 2004年第3期11卷 216-220页

作者： Fanxiu Lu Wubao Yang Zhilin Liu Weizhong Tang Yumei Tong Materials science and engineering school, {3. of science and Technology beijing, beijing 100083. china Materials science and engineering school University of Science and Technology Beijing Beijing 100083 China

Adherent nano diamond films were successfully deposited on glass substrate bymicrowave plasma assisted CVD method in H_2-CH_4 and Ar-CH_4 environment. Raman, AFM (Atomic ForceMicroscope), TEM (Transmission Electron Microscope), FTIR, and Nano Indentation techniques were usedfor characterization of the obtained nano diamond films. It was found that the average grain sizewas less than 100 nm with a surface roughness value as low as 2 nm. The nano diamond films werefound to have excellent transparency in visible and IR spectrum range, and were as hard as naturaldiamond. Experimental results were presented. Mechanisms for nano diamond film deposition werediscussed.

关键词： nano diamond films microwave plasma assisted CVD characterization glasssubstrate

Microstructure Study on Semi-solid 60Si2Mn during Compressing

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Journal of university of science and Technology beijing 2001年第2期8卷 115-118页

作者： Yonglin Kang, Xiongfei Yang, Renbo Song, Weimin Mao, Maosheng Yang (Material science & engineering school, {3. of science and Technology beijing, beijing 100083. china) Material Sci. and Eng. school University of Science and Technology Beijing 100083 China

The microstructure behavior and deformation mechanism of semi-solid 60Si2Mn fabricated by electromagnetic stirring under different deformation conditions during thixoforming are studied by means of Gleeble-1500 thermal-strain-stress simulator. The micro- structure of deformed 60Si2Mn and that of the non-deformed are compared. The results show that the grain size within deformation zone decreases as the amount of deformation increases or deformation temperature decreases, but deformation fate has small effect on grain size when the rate is very low. Besides, there is a critical amount of deformation to reduce grain size. These results offer theoretical and experimental basis for further producing semi-solid material with high melting temperature and direct forming of semi-solid slurry.

关键词： semi-solid microstructure grain size segregation, reduction

Fluid Flow Behavior of Liquid in Cylindrical Vessels Stirred by One or Two Air Jets

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International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 170-177页

作者： Lifeng Zhang, Shoji Taniguchi, Kaike Cai, ying Qu ( Department of Metallurgy Graduate school of engineering, Tohoku {3., Sendai 980-579 Japan Metallurgy school, {3. of science and Technology beijing, beijing 100083. china) Department of Metallurgy Graduate School of Engineering Tohoku University Sendai 980-8579 Japan Metallurgy school University of Science and Technology Beijing Beijing 100083 China

Based on the two-phase model (Eulerian-Eulerian model), the three dimensional fluid flow in water and that liquid steel systems stirred by one or two multiple gas jets are simulated. In the Eulerian-Eulerian two-phase model, the gas and the liquid phase are considered to be two different continuous fluids interacting with each other through the finite inter-phase areas. The exchange between the phases is represented by source terms in conversation equations. Turbulence is assumed to be a property of the liquid phase. A new turbulence modification - model is introduced to consider the bubbles movement contribution to and . The dispersion of phases due to turbulence is represented by introducing a diffusion term in mass conservation equation. The mathematical simulation agrees well with the experiment results. The study results indicate that the distance of two nozzles has big effect on fluid flow behavior in the vessel. Using two gas injection nozzles at the half radii of one diameter of the bottom generates a much better mixing than with one nozzle under the condition of the same total gas flow rate.

关键词： fluid flow two-phase Eulerian-Eulerian model model mathematical simulation

Surface hardening of Fe-based alloy powders by Nd:YAG laser cladding followed by electrospark deposition with WC-Co cemented carbide

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Rare Metals 2010年第4期29卷 380-384页

作者： WANG Jiansheng,MENG Huimin,YU Hongying,FAN Zishuan,and SUN Dongbai school of Materials science and {3.,university of science and Technology beijing,beijing 100083.china school of Materials science and engineering University of Science and Technology Beijing Beijing China

This paper presents the results of a study concerned with the surface hardening of Fe-based alloys and WC-8Co cemented carbide by inte- grating laser cladding and the electrospark deposition processes. Specimens of low carbon steel were processed firstly by laser cladding with Fe-based alloy powders and then by electrospark deposition with WC-SCo cemented carbide. It is shown that, for these two treatments, the electrospark coating possesses finer microstructure than the laser coating, and the thickness and surface hardness of the electrospark coating can be substantially increased.

关键词： laser cladding electrospark deposition surface hardening Fe-based alloy cemented carbide

Relaxation of Deformed Austenite and Refinement of Bainite in a Nb-Containing Microalloyed Steel

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Journal of university of science and Technology beijing 2001年第3期8卷 214-217页

作者： Shanwu Yang, Xuemin Wang, Chengjia Shang, Xinlai He, Yi Yuan Material science and engineering school, {3. of science and Technology beijing, beijing 100083. china Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

By means of stress relaxation and strain-induced precipitation in deformed austenite, bainite with micron sheaves size was obtained in Nb-containing steel. Microstructures of deformed samples isothermally relaxed for various time followed by cooling in water were examined. Stress relaxation test and transmission electron microscopy (TEM) were employed to detect precipitation of microalloy elements, such as Nb, Ti, during isothermal holding after deformation. All the samples were constituted by lath-like bainite along with acicular ferrite, but the size of bainitic sheaves and the amount of acicular ferrite were changed with relaxation time. To achieve optimum refinement, relaxation should be confined in the stage when the precipitates have sufficiently grown and started to coarsen. The sample having not undergone relaxation does not exhibit obvious refinement despite of its higher dislocation density. These results indicate that relaxation promotes bainite to refine, which is because deformed austenitic grains are divided by dislocation walls formed during relaxation and acicular ferrite formed before bainitic transformation.

关键词： stress relaxation strain induced precipitation refinement

Stability of Ultra-fine Microstructures during Tempering

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Journal of university of science and Technology beijing 2001年第2期8卷 119-122页

作者： Shanwu Yang, Chengjia Shang,Xinlai He, Xuemin Wang, Yi Yuan (Material science and engineering school, {3. of science and Technology beijing, beijing 100083. china) Univ Sci & Technol beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China

The stability of ultra-fine microstructure during tempering at 650 degreesC was investigated on a Nb-containing steel. The steel had undergone 5 passes controlled rolling, then was relaxed lair cooled) to 73. degreesC: and cooled in water. The evolution of microstructure was that, in early stage of tempering, no obvious change was detected by means of optical microscopy while dislocation cells were formed inside bainitic laths. With further tempering, bainitic laths started to coalesce in some regions. Finally, polygonal ferrite was formed while hardness decreased dramatically. Some samples taken from the same primary plate were reheated at 93. degreesC for 0.5 h followed by quenching into water before tempering. Despite their lower original hardness, the reheated samples softened Faster during tempering. Ferrite was quickly formed in the reheated samples. These results indicate that the evolution of microstructures towards equilibrium during tempering of the steel is mainly determined by whether dislocations are pinned rather than the dislocation density.

关键词： microalloyed steel bainite tempering

A new intelligent prediction system model-the compound pyramid model

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science china(Information sciences) 2012年第3期55卷 723-736页

作者： YANG BingRu , QU Wu, WANG LiJun & ZHOU ying school of Information engineering, {3. of science and Technology beijing, beijing 100083. china 1. school of Information engineering University of Science and Technology Beijing Beijing 100083 China

A current development trend in research on intelligent systems is to optimize a general intelligent prediction system into an individuation intelligent prediction system that is applied in specialized fields. Protein structure prediction is a challenging international issue. In this paper, we propose a new intelligent prediction system model, designed as a multi-layer compound pyramid model, for predicting secondary protein structure. The model comprises four independent intelligent interfaces and several knowledge discovery methods. The model penetrates throughout the domain knowledge, with the effective attributes chosen by Causal Cellular Automata. Furthermore, a high pure structure database is constructed for training. On the RS126 dataset, the overall state per-residue accuracy, Q3. reached 83.99%, while on the CB513.dataset, Q3.reached 85.58%. Meanwhile, on the CASP8 sequences, the results are superior to those produced by other methods, such as Psipred, Jpred, APSSP2 and BehairPred. These results confirm that our method has a strong generalization ability, and that it provides a model for the construction of other intelligent systems.

关键词： knowledge discovery intelligent prediction system model compound pyramid model

A Special TMCP Used to Develop a 800MPa Grade HSLA Steel

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Journal of university of science and Technology beijing 2001年第3期8卷 224-228页

作者： Chengjia Shang,Xuemin Wang, Xinlai He, Shanwu Yang, Yi Yuan Material science and engineering school, {3. of science and Technology beijing, beijing, 100083. china Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

The effect of relaxation after finished rolling on structures and properties of four microalloyed steel with different content of Nb and Ti was investigated. By alloy designing and control rolling + relaxation-precipitation-control phase trail storm ati on (RPC) process, a new 800 MPa grade HSLA plate steel could be obtained, the microstructure is composite ultra-fine lath bainite/martensite. The tempering process and mechanical properties of this kind of HSLA steel were investigated. The yield strength can achieve 800 MPa, and the ductility and impact toughness is satisfied.

关键词： HSLA steel microstructure and mechanical properties TMCP (thermomechanical control process) RPC