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Nanostructured Sulfide Composite Coating Prepared by Atmospheric Plasma Spraying

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材料工程 2006年第Z1期34卷 281-284页

作者： GUAN Yao-hui~1,XU Yang~1,ZHENG Zhong-yu~2,TONG Xiao-hui~2(1 Engineering College of china Agricultural University,beijing 100083.china 2 beijing research Institute of mechanical & electrical technology,beijing 100083.china) Engineering College China Agricultural University Beijing 100083 China beijing research Institute of mechanical and {3. technology Beijing 100083 China

Nanostructured FeS-SiC coating was deposited by atmospheric plasma spraying（APS）.The microstructure and phase composition of the coating were characterized with SEM and XRD,*** addition,the size distribution of the reconstituted powders and the porosity of the coating have been *** was found that the reconstitiuted powers with sizes in the range of 20 to 80 μm had excellent flowability and were suitable for plasma spraying *** as-sprayed FeS-SiC composite coating exhibited a bimodal distribution with small grains（3.～80nm） and large grains（100～200nm）.The coating was mainly composed of FeS and SiC,a small quantity of Fe1-xS and oxide were also *** porosity of the coating was approximately 19%.

关键词： plasma spraying nanostructured FeS-SiC composite coating

Parameter identification theory of a complex model based on global optimization method

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Science china(Physics,Mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1, JIN QuanLin2 & XU BingYe3.1 College of Automotive Engineering, South china University of technology, Guangzhou 510640, china 2 {3. research Institute of mechanical and electrical technology, beijing 100083. china 3.Department of Engineering Mechanics, Tsinghua University, {3. 100084, china 1. College of Automotive Engineering South China University of Technology Guangzhou 510640 China 2. beijing research Institute of mechanical and {3. technology Beijing 100083 China 3. Department of Engineering Mechanics Tsinghua University Beijing 100084 China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely applied to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the design of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 927°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the designed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization

The precipitation and effect of nano nitrides in HSLC steel

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Science china(Technological Sciences) 2008年第7期51卷 989-998页

作者： FU Jie1, LIU YangChun1,2 & WU HuaJie1,3.1 School of Metallurgical and Ecological Engineering, University of Science and technology beijing, beijing 100083. china 2 Shougang technology research Institute, Shougang (Group) Corporation, beijing 100041, china 3.Metallurgical Engineering research Institute, University of Science and technology beijing, beijing 100083. china 1. School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China 2. Shougang technology research Institute Shougang (Group) Corporation Beijing 100041 China 3. Metallurgical Engineering research Institute University of Science and Technology Beijing Beijing 100083 China

The existing forms of N and Al in HSLC (high strength low carbon) steel produced by TSCR (thin slab casting and rolling process), the precipitation thermodynamics and kinetics of AlN, and its effects on structure and mechanical property are studied. The experimental results show that only a small quantity of nitrogen is com- bined into AlN in HSLC steel produced by TSCR and most of the nitrogen in steel is still free nitrogen. Aluminum-nitride is mainly precipitated during the period of slow air cooling after coiling, but not during rolling and water cooling. The acid-soluble aluminum has no obvious effect on the grain size and mechanical property of HSLC steel produced by TSCR whose acid-soluble aluminum content is 0.005%―0.043.. The precipitation of AlN is not the main cause of grain refinement of HSLC steel produced by TSCR, nor is AlN the dominating precipitate that has precipitation strengthening effect. The nano nitrides are not pure AlN, but have complex compositions.

关键词： thin slab casting and rolling high strength low carbon steel AlN nano nitride precipitation strengthening

Mathematical Model for the Drying Process of Granular Materials in a Fluidized Bed

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 296-300页

作者： Xiulan Huai, Li Wang, Zhiyun Qu ( mechanical Engineering School, University of Science and technology beijing,{3. Chemical Industry research Institute of Shanxi, Taiyuan 03.03., china) mechanical Engineering School University of Science and Technology Beijing Beijing 100083 China Chemical Industry research Institute of Shanxi Taiyuan 030031 China

The experiment of granular materials, barley, drying in a fluidized bed was carried out to investigate the influence of the factors, inlet air temperature, air moisture, bed height and original moisture content of the dried materials on drying process. Based on the experimental data, a corresponding mathematical model is presented. As a conclusion, a higher inlet air temperature and a reasonable bed height should be used so as to increase the dring rate and to improve the product quality.

关键词： fluidization granular materials drying, experimental investigation mathematical model Information

Cutting Performance and Mechanism of RE Carbide Tools

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Rare Metals 2001年第3期20卷 197-201页

作者： Jianbing Cheng, Yufang Wu, Qixun Yu 1) Department of mechanical Engineering, beijing technology and Business University, beijing 10003., china 2) College of mechanical Engineering and Automation, beijing Institute of technology beijing 100081, china beijing Technol & Business Univ Dept Mech Engn Beijing 100037 Peoples R China beijing Inst Technol Coll Mech Engn & Automat Beijing 100081 Peoples R China

The research of rare earth elements (RE), added into cemented carbide tools, is one of the recent developments of new types of tool materials in china. Systematic experiments about RE carbides YG8R. (K3.), YT14R (P20) and, YW1R (M10) were made to study on the cutting performance in comparison with non-RE carbides YG8, YT14 and YW1. The cutting experiments were as follows: tool life, cutting force, tool-chip friction coefficient and interrupted machining. The action of RE on the carbide materials and the cutting mechanism of the RE carbide tools in the cutting process were verified with the aid of SEM and energy spectrum analysis. Experimental results show that the RE carbide tools have a good overall performance.

关键词： rare earth elements cemented carbide tool cutting performance cutting mechanism

research on Vibration Properties of the Drill-punch Mechanism for Taphole Drill

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Journal of University of Science and technology beijing 2001年第4期8卷 311-313页

作者： Jianping Liu, Yongfang Liao 1) mechanical Engineering School, University of Science and technology beijing.{3. 2) Shanghai Baoshan Iron & Steel Corporation. Shanghai 201914, china Univ Sci & Technol beijing Sch Mech Engn Beijing 100083 Peoples R China Shanghai Baoshan Iron & Steel Corp Shanghai 201914 Peoples R China

A new type taphole drill was designed. The vibration properties of them drill-punch mechanism for the new type taphole drill were researched, the laws of its inherent characteristics were found. The measures to add punch amplitude and to reduce traverse vibration were put forward. The result showed that decreasing the frequency of vibration motors or increasing the stiffness of springs, and increasing excitation force can improve the vibration properties of the properties of the drill-punch mechanism.

关键词： taphole drill equipment in the cast house vibrating machinery

Numerical Analysis of Hydroforming Deep Drawing of Conical Cup

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Journal of Materials Science & technology 2001年第1期17卷 131-132页

作者： Yongming KONG Xianbin ZHOU and Min LI research Center of Sheet Metal Forming, School of mechanical Engineering & Automation, beijing University of Aeronautics & Astronautics,{3. beijing Univ Aeronaut & Astronaut Sch Mech Engn & Automat Res Ctr Sheet Met Forming Beijing 100083 Peoples R China

Aided by the FE-code. analysis is carried to find the proper hydroforming deep-drawing condition for the perfect forming of a conical cup that can not be drawn successfully by conventional deep drawing method. Hydraulic counter pressure must be reasonably controlled, otherwise defects such as fracture and wrinkling can not be avoided. Therefore, the forming procedure is divided into three stages, and the counter pressure is adjusted intentionally to make the blank clamped onto the punch at a suitable time, then deformation at dangerous area is resisted by the effect of the counter pressure and the conical cup can be formed without defects.

关键词： Numerical Analysis of Hydroforming Deep Drawing of Conical Cup Figure

Thermal-mechanical coupled effect on fracture mechanism and plastic characteristics of sandstone

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Science china(Technological Sciences) 2007年第6期50卷 833-843页

作者： ZUO JianPing1,2, XIE HePing2,3. ZHOU HongWei1,2 PENG SuPing1 1 State Key Laboratory of Coal Resources and Safe Mining, china University of Mining and technology, beijing 100083. china 2 Institute of Rock Mechanics and Fractals, china University of Mining and technology, beijing 100083. china 3.Sichuan University, Chengdu 610065, china 1. State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology Beijing 100083 China 2. Institute of Rock Mechanics and Fractals China University of Mining and Technology Beijing 100083 China 3. Sichuan University Chengdu 610065 China

Scanning electronic microscopy (SEM) was employed to investigate fractographs of sandstone in mine roof strata under thermal-mechanical coupled effect. Based on the evolution of sandstone surface morphology in the failure process and frac- tography, the fracture mechanism was studied and classified under meso and mi- cro scales, respectively. The differences between fractographs under different tem- peratures were examined in detail. Under high temperature, fatigue fracture and plastic deformation occurred in the fracture surface. Therefore, the temperature was manifested by these phenomena to influence strongly on micro failure mechanism of sandstone. In addition, the failure mechanism would transit from brittle failure mechanism at low temperature to coupled brittle-ductile failure mechanism at high temperature. The variation of sandstone strength under differ- ent temperature can be attributed to the occurrence of plastic deformation, fatigue fracture, and microcracking. The fatigue striations in the fracture surfaces under high temperature may be interpreted as micro fold. And the coupled effect of tem- perature and tensile stress may be another formation mechanism of micro fold in geology.

关键词： sandstone, thermal-mechanical coupled effects, fractograph, plastic deformation, SEM, micro fold

Effects of Cobalt on the Sintering Behavior of mechanically Activated Tungsten Powder

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Rare Metals 2001年第3期20卷 183-186页

作者： Chengchang Jia, Xiaoyang Liu, Xiuhu Guan, Xuekuan Su, Jun Zhao, Zizhang Xie 1) Materials Science and Engineering School, University of Science and technology beijing, beijing 100083. china 2) beijing research Institute of Powder Metallutrgy, beijing 10005 Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China beijing Res Inst Powder Met Beijing 100053 Peoples R China beijing Polytech Univ Beijing 100022 Peoples R China

Tungsten alloys were prepared with mechanically activated powder added microelement cobalt in order to improve the process and properties of alloys. Properties of alloys such as density, hardness and bending strength were measured. The results show that through mechanical activation, cobalt can accelerate the sintering process of these alloys By the combination of mechanical activation and adding microelement cobalt, tungsten alloys with higher density and better properties can be obtained.

关键词： powder metallurgy tungsten alloys cobalt mechanical activation sintering behavior