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Analysis and Control on Fracture of 20Mn2A High Tensile Steel for Round Link Chain

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Journal of Iron and Steel Research International 2011年第S1期18卷 898-902页

作者： CAO Shu-wei 1,2,KANG Yong-lin 1,3,ZHAO Xian-ping 2,YANG Chang-chun 1 (1.School of materials Science and Engineering,university of Science and technology beijing,beijing 100083,china 2.technology Center of Anyang Iron & Steel Group Co.,Ltd.,Anyang 455004,Henan,china 3.State key laboratory for advanced Metals and materials,university of Science and technology beijing,beijing 100083,china) Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Anyang Iron & Steel Grp Co Ltd Ctr Technol Anyang 455004 Henan Peoples R China Univ Sci & Technol beijing State Key Lab Adv Met & Mat Beijing 100083 Peoples R China

Based on the phenomenon of brittle fracture occurred during tensile test for 20Mn2A high strength circular chain used in coal mines,the fracture property is regarded as intercrystalline brittle one after macroscope observation and metallographic *** is analysed that the intercrystalline brittle fracture is due to high tempering temperature and limited processing site where final products are piled together after heat treatment,which lead to a lower cooling rate of internal chain,with Si,Mn and P etc elements segregating and enriching in the austenite grain boundary and forming high tempering *** these circular chains are tempered again for one hour at 670℃,and oil-cooled rapidly,due to the reversibility of high temper brittleness for structural alloy steel,the high temper brittleness can be eliminated and products are completely qualified after tensile inspection.

关键词： high strength circular chain metallographic examination brittle fracture high tempering brittleness improvement measures

Nanocrystalline exchange-coupled Pr-Fe-B permanent magnets

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International Journal of Minerals,Metallurgy and materials 1997年第3期11卷 11-13页

作者： WANG Zuocheng ZHANG Maocai QIAO Yi GAO Xuexum LI Fubiao ZHOU Shouzeng WANG Run( State key laboratory for advanced Metals and materials, university of Science and technology beijing, beijing 100083, china) ( materials Science and Engineering School,

Nanocomposite Pr2Fe14B/α-Fe permanent magnets were prepared by melt spinning and subsequent crystallizahon of Pr8Fe86B6, amorphous Precursnors. The microstructure is a two-phase nanocomposite of Pr2 Fe14 B and softmagnetic α-Fe with an average size of 30nm. X-ray diffration, Thermomagnetic analysis and TEM analy0sis indicatetha amorphous Pr8Fe86B6, alloy crystallizes through the process of Am→Am→Am'+α-Fe→Pr2Fe23B3+α-Fe-Pr2Fe14B+α-FeThe highest value of remanence (Br), cocreivity (Hci) and maximum energy Product ((BH)max) of the nanocrystallinealloys are 1.10T, 340 kA/m and 110 kJ/m3 respechvely, exhibihng remarkable remanence enhancement. The effect ofannaling temperature and time on the microstructure and magnetic properties was also studied. The resultS show thatappropriate annealing temperature and time are important for obtaining the optimal microstructure and the bestmagnetic properties.

关键词： nanocomposite magnet exchange coupling remanence enhancement

advanced fluid-typing methods for NMR logging

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Petroleum Science 2011年第2期8卷 163-169页

作者： Xie Ranhong Xiao Lizhi State key laboratory of Petroleum Resource and Prospecting China University of Petroleum Beijing 102249 China key laboratory of Earth Prospecting and Information technology China University of Petroleum Beijing 102249 China

In recent years, nuclear magnetic resonance （NMR） has been increasingly used for fluid- typing in well-logging because of the improved generations of NMR logging tools. This paper first discusses the applicable conditions of two one-dimensional NMR methods： the dual TW method and dual TE method. Then, the two-dimensional （T2, D） and （T2, T1） NMR methods are introduced. These different typing methods for hydrocarbon are compared and analyzed by numerical simulation. The results show that the dual TW method is not suitable for identifying a macroporous water layer. The dual TE method is not suitable for typing gas and irreducible water. （T2, T1） method is more effective in typing a gas layer. In an oil-bearing layer of movable water containing big pores, （T2, T1） method can solve the misinterpretation problem in the dual TWmethod between a water layer with big pores and an oil layer. The （T2, T1） method can distinguish irreducible water from oil of a medium viscosity, and the viscosity range of oil becomes wide in contrast with that of the dual TW method. The （T2, D） method is more effective in typing oil and water layers. In a gas layer, when the SNR is higher than a threshold, the （T2, D） method can resolve the overlapping T2 signals of irreducible water and gas that occurs due to the use of the dual TE method. Twodimensional NMR for fluid-typing is an important development of well logging technology.

关键词： NMR logging one-dimensional NMR two-dimensional NMR reservoir evaluation fluidtyping

EAM Analysis of the Lattice Parameter Effect in Order-Disorder Transformation

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Journal of university of Science and technology beijing 2001年第3期8卷 189-194页

作者： Timoth■e Nsongo, Xiaodong Ni, Guoliang Chen State key laboratory for advanced Metals and materials, university of Science and technology beijing, beijing 100083, china Faculty of Science, Physics Department, P. O. Box 69, Brazzaville (CONGO) Applied Scie State key Lab. for Adv. Met. Mat. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The embedded atom method (EAM) was used to theoretically analyze the effect of the lattice parameter variation on the order-disorder transformation in binary alloys. Based on EAM, it is found that only one kind of order-disorder transition (second-order transition) exists for AB alloy. Three groups of order-disorder transformation can be observed for the A(3)B or AB(3) compounds. For group I, the order-disorder is a completely first-order transition. For group II, the order-disorder transformation is a classical first-order transition. For group III, the order-disorder transformation is found to be a second-order transition. The lattice parameter variations have a significant effect on E-2 coefficient, which is related to the ordering energy. These results are in good agreement with experiments.

关键词： order-disorder transformation embedded atom method (EAM) phase transformation binary alloy

Redevelopment of liftoff rates of saltating sand grains based on a simple optimization model

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Science china Earth Sciences 2010年第4期53卷 568-574页

作者： CHENG Hong & ZOU XueYong State key laboratory of Earth Surface Processes and Resource Ecology,beijing Normal university,beijing 100875,china MOE Engineering Center of Desertification and Blown-sand Control,beijing Normal university,beijing 100875,china key laboratory of Environmental Change and Natural Disaster of the Ministry of Education of china,beijing Normal university,beijing 100875,china State key laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University Beijing China MOE Engineering Center of Desertification and Blown-sand Control Beijing Normal University Beijing China key laboratory of Environmental Change and Natural Disaster of the Ministry of Education of china Beijing Normal University Beijing China

This paper is a redevelopment result of liftoff rates of saltating sand grains based on our previous *** sand flow is a complex multi-phase flow because of a special two-phase gas-solid flow near ground *** extensive research on the movement of blowing sand,no model fully characterizes aeolian sand flow,and large differences often exist between simulations of aeolian sand movement and field *** key problem is a few of sufficient research on liftoff rates of saltating sand grains(also called the number of liftoff sand grains per unit time and per unit bed area).It is necessary to re-search in advance liftoff rates of saltating sand *** redeveloped liftoff rates of saltating sand grains by establishing an optimization model based on the flux of aeolian sand flow at different heights of the sampler in wind tunnel and the simulated capture of saltating sand grains by different heights of the sampler that are from different liftoff position(distance from the sampler) in order to revise previous inversion condition of liftoff rates of saltating sand *** rates increased rapidly with increasing wind *** frictional wind velocities of u=0.67,0.77,0.82,0.83,and 0.87 m s-1,liftoff rates were 3840,954502,5235114,5499407,and 7696291 sand grain s-1 m-2,*** rates could be expressed as the square of the instantaneous frictional wind velocity and a constant(0.663) that differs from the critical(threshold) frictional wind velocity at which saltation *** our results require additional experimental validation and the simple optimization model must be improved,they nonetheless provide a strong basis for future research.

关键词： liftoff rates of saltating sand grains optimization model wind tunnel two-phase gas-solid flow

Surface recrystallization of a Ni_3Al based single crystal superalloy at different annealing temperatures and blasting pressure

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Rare Metals 2012年第3期31卷 209-214页

作者： WU Yuxiao a, YANG Ruibo a, LI Shusuo a, MA Yue a, GONG Shengkai a, and HAN Yafang a, b a key laboratory of Aerospace materials and Performance (Ministry of Education), School of materials Science and Engineering, beijing university of Aeronautics and Astronautics, beijing 100191, china b beijing Institute of Aeronautical materials, beijing 100095, china key laboratory of Aerospace materials and Performance (Ministry of Education) School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Beijing China beijing Institute of Aeronautical materials Beijing China

The effects of annealing temperature and grit blasting pressure on the recrystallization behavior of a Ni3Al based single crystal superalloy were studied in this work. The results show that the precipitation of the Y-NiMo phase occurs at 900 and 1000 °C, which precedes recrystallization. The initial recrystallization temperature was between 1000 and 1100 °C. Cellular recrystallization was formed at 1100 and 1200 °C, which consisted of large columnar γ′ and fine γ + γ′. The dendrite arm closed to the interdendritic region may act as nucleation sites during initial recrystallization by a particle simulated nucleation mechanism at 1280 °C. The size of the grains first turned large and then became small upon the pressure while the recrystallization depth increased all the time.

关键词： recrystallization temperature pressure Ni3Al based single crystal superalloy nucleation

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

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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

Measurement Methodology for Monitoring Fouling Resistance in Condenser of Chiller

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湖南大学学报（自然科学版） 2009年第S1期36卷 119-122页

作者： YU Dan1,3,GAN Li-si1,CAO Yong2(1.beijing university of technology,beijing 100022,china 2.Build Environment and Energy Efficiency,china Academy of Building Research,beijing 100013,china 3.beijing Institute of Civil Engineering and Architecture,beijing 100044,china) beijing university of technology Beijing 100022 China beijing Institute of Civil Engineering and Architecture Beijing 100044 China Build Environment and Energy Efficiency China Academy of Building Research Beijing 100013 China

This paper established an on-line monitoring model for fouling resistance of cooling water based on heat transfer theory,which was mainly applied to the fouling resistance test for condenser of chiller in operation,and the test requirements were *** proves that the load ratio of chiller has big influence on the test result,and the best load ratio for test is the range of 80%～100%.A case has been executed to validate the model's feasibility.

关键词： fouling resistance monitoring condenser cooling water

Wide/narrow azimuth acquisition footprints and their effects on seismic imaging

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Petroleum Science 2008年第4期5卷 308-313页

作者： Di Bangrang Xu Xiucang Wei Jianxin key laboratory of CNPC Geophysical Exploration China University of Petroleum Beijing 102249 China State key laboratory of Petroleum Resource and Prospecting China University of Petroleum Beijing 102249 China key laboratory of Earth Prospecting and Information technology China University of Petroleum Beijing 102249 China

Acquisition footprint is a new concept to describe the seismic noise in three-dimensional seismic exploration and it is closely related to geometry and observation shuttering. At present, the study on acquisition footprints has become a hot spot. In partnership with the Dagang Oilfield, we used the channel sand body seismic physical model to study the characteristics of wide/narrow azimuth acquisition footprints and analyzed and compared the two types of footprints and their effects on target imaging. In addition, the footprints caused by data processing of the normal moveout offset （NMO） stretching aberration were discussed. These footprints are located only in the shallow or middle layer in the time slice, and possibly affect the imaging of shallow target layers, and have no influence on deep target imaging. Seismic physical modeling has its advantages in the study of acquisition footprints.

关键词： Wide/narrow azimuth geometry acquisition footprint stretching aberration time slice seismic imaging