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1Proso Millet Protein Elevates Plasma Level of High-Density Lipoprotein:A New Food Function of Proso Millet显示文摘We examined the effects of dietary proso-millet protein on plasma levels of high-density lipoprotein (HDL) cholesterol in different rats from animals reported in our previous studies. The results showed also, in this animal, that the ingestion of the millet protein elevates plasma levels of HDL-cholesterol like our earlier works. Taking into account the anti-atherogenic function of HDL, therefore, the millet protein would be useful as a new food ingredient which has the function that regulates cholesterolN. NISHIZAWA S. SHIMANUKI H. FUJIHASHI H. WATANABE Y. FUDAMOTO AND T. NAGASAWA (Department of Bioscience and Technology, Faculty of Agriculture, Iwate University Morioka, Iwate 020, Japan Research Laboratory,Nitto Best Co., Ltd, Sagae, Yamagata 991 Ka 1996Biomedical and Environmental Sciences1996,9,2:24
2A statistical model for porous structure of rocks显示文摘The geometric features and the distribution properties of pores in rocks were in- vestigated by means of CT scanning tests of sandstones. The centroidal coordi- nates of pores, the statistic characterristics of pore distance, quantity, size and their probability density functions were formulated in this paper. The Monte Carlo method and the random number generating algorithm were employed to generate two series of random numbers with the desired statistic characteristics and prob- ability density functions upon which the random distribution of pore position, dis- tance and quantity were determined. A three-dimensional porous structural model of sandstone was constructed based on the FLAC3D program and the information of the pore position and distribution that the series of random numbers defined. On the basis of modelling, the Brazil split tests of rock discs were carried out to ex- amine the stress distribution, the pattern of element failure and the inosculation of failed elements. The simulation indicated that the proposed model was consistent with the realistic porous structure of rock in terms of their statistic properties of pores and geometric similarity. The built-up model disclosed the influence of pores on the stress distribution, failure mode of material elements and the inosculation of failed elements.JU Yang1,2, YANG YongMing1, SONG ZhenDuo3 & XU WenJing4 1 State Key Laboratory of Coal Resources and Safe Mining, China University of Mining & Technology, Beijing 100083, China 2 Department of Mechanical and Manufacturing Engineering, The University of Calgary, 2500 University Drive NW Calgary, AB T2N 1N4, Canada 3 China National Coal Mining Equipment Co. Ltd, Beijing 100011, China 4 Department of Materials and Metallurgy, The University of Utah, Salt Lake City, Utah 84112, USA 2008Science China(Technological Sciences)2008,51,11:21
3Dynamic feedback robust stabilization of nonholonomic mobile robots based on visual servoing显示文摘This paper investigates the visual servoing robust stabilization of nonholonomic mobile robots. The calibration of visual parameters is not only complicated, but also needs great consumption of calculated time so that the accurate calibration is impossible in some situations for high requirement of real timing. Hence, it is interesting and important to consider the design of stabilizing controllers for nonholonomic kinematic systems with uncalibrated visual parameters. A novel uncertain model of these nonholonomic kinematic systems is proposed. Based on this model, a stabilizing controller is discussed by using dynamic feedback and two-step techniques. The proposed robust controller makes the mobile robot image pose and the orientation converge to the desired configuration despite the lack of depth information and the lack of precise visual parameters. The stability of the closed loop system is rigorously proved. The simulation is given to show the effectiveness of the presented controllers.Chaoli WANG 1 , Zhenying LIANG 2 , 3 , Qingwei JIA 4 (1.Department of Control Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China 2.Business School, University of Shanghai for Science and Technology, Shanghai 200093, China 3.School of Science, Shandong University of Technology, Zibo Shandong 255049, China 4.Research & Development Centre, Hitachi Asia Ltd, Hitachi Tower, Singapore 049318) 2010控制理论与应用(英文版)2010,8,2:13
4POLYMER CHARGE AND MOLECULAR WEIGHT EFFECTS ON TREATED IRRIGATION FURROW PROCESSES显示文摘Application of 5-10 mg L-1 water soluble anionic polyacrylamide (PAM) to furrow irrigation water during flow advance substantially reduces sediment loss and increases net infiltration. We hypothesized that PAM_s solvated molecular conformation influences its irrigation-management efficacy. The study was conducted in Kimberly, Idaho, on Portneuf silt loam (Durinodic Xeric Haplocalcids), under furrowirrigated beans (Phaseolus vulgaris ) at a 1.5% slope. Polyacrylamides with contrasting molecular weight (anionic; 4-7, 12- 15 and 14-17 MDa, i.e. Mg mol-1 ), charge type (neutral, anionic, cationic), and charge density (8, 19, 35 mol %) were tested in two studies. Inflow rate was 23 L min-1 during furrow advance, and 15 L min-1 for the remaining set. Anionic and neutral PAMs were twice as effective as cationic PAMs for controlling sediment loss in new furrows. The order of effectiveness for overall soilloss control was : anionic >neutral >cationic PAM, and efficacy increased with increasing charge density and/or molecular weight. Net furrow infiltration increased by 14 to 19% when PAM treatment molecular weight was reduced from 17 to 4 MDa. General trends suggested that medium and high charge density anionic and neutral PAM produced the greatest increase in infiltration compared with controls.Compared with untreated furrows, neutral PAM gave the greatest season-long net infiltration gains (5%),while charged PAMs tended to increase net infiltration early in the season on new furrows but decreased infiltration on repeat-irrigated furrows later in the season.R. D. Lentz(USDA-ARS, Northwest Irrigation and Soils Research Laboratory, Kimberly, ID)R. E. Sojka (Landcare Research, New Zealand, Ltd, Palmerston North, New ZealandNote: The manucript of this paper was received in March 1999, Discussion open until March 2000International Journal of Sediment Research2000,15,1:13
5Tension and Thickness Control Strategy Analysis of Two Stands Reversible Cold Rolling Mill显示文摘In order to lucubrate the rolling characteristic of the two stands reversible cold rolling mill and establish the tension and thickness control strategy, the steady-state characteristic simulating program was established using the steady-state continuous rolling theory. The influences of each factor on exit thickness under different tension control methods were analyzed. The results show that, the influence of the entry stand gap on exit thickness is significant and it changes little with different tension control methods. As a result, the entry stand gap can be used as the main control method of exit thickness, whereas rolling speed of any stand and roll gap of the exit stand can be used to adjust the inter-stand tension. The results are beneficial for thickness and tension control of the two stands reversible cold rolling mill.LIU Guang-ming1, DI Hong-shuang2, ZHOU Cun-long1, LI Hong-cui3, LIU Jiang3 (1. College of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, Shanxi, China 2. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, Liaoning, China 3. Cold Rolling Plant, Jinan Iron and Steel Group Co Ltd, Jinan 250101, Shandong, China) 2012Journal of Iron and Steel Research(International)2012,19,10:12
6HCWCI/Carbon Steel Bimetal Liner by Liquid-Liquid Compound Lost Foam Casting显示文摘Impact, friction and corrosion from the grinding balls and the grinding medium during the mineral processing result in liner breakage. Liner, made from Hadfield steel or alloyed steel, could not have served in wet grinding environment for more than ten months. Composite liner, made from HCWCI (high Cr white cast iron) and carbon steel, has been developed successfully with liquid-liquid composing process based on LFC (lost foam casting). The microstructure of composite was analyzed with optical microscope, SEM (scanning electron microscope)/EDX energy-dispersive X-ray and XRD (X-ray diffraction). According to micrograph, the combination region of two metals was staggered like dogtooth, no mixtures occurred between two liquid metals, and its interface presented excellent metallurgical bonding state. The results of mechanical property test show that, the hardness of HRC, the fracture toughness, and the bending strength are more than 61, 16.5 J/cm2 and 1 600 MPa, respectively. Comparison between liners made from bimetal composite and alloyed steel has also been investigated in industrial hematite ball mill. The results of eight months test in wet grinding environment prove that the service life of bimetal composite liner is three times as long as that of one made from alloyed steel.XIAO Xiao-feng1,2, YE Sheng-ping2, YIN Wei-xin3, XUE Qiong4 (1. School of Mechanical Engineering and Automation, Wuhan Textile University, Wuhan 430073, Hubei, China 2. State Key Laboratory of Material Processing and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China 3. Wuhan Zhike Abrasive-Resistant Material Science and Technology Development Co Ltd, Wuhan 430073, Hubei, China 4. College of Science, Wuhan University of Technology, Wuhan 430079, Hubei, China) 2012Journal of Iron and Steel Research(International)2012,19,10:11
7Dome Combustion Hot Blast Stove for Huge Blast Furnace显示文摘In Shougang Jingtang 5 500m 3 huge blast furnace ( BF ) design , dome combustion hot blast stove ( DCHBS ) technology is developed.DCHBS process is optimized and integrated , and reasonable hot blast stove ( HBS ) technical parameters are determined.Mathematic model is established and adopted by computational fluid dynamics ( CFD ) .The transmission theory is studied for hot blast stove combustion and gas flow , and distribution results of HBS velocity field , CO density field and temperature field are achieved.Physical test model and hot trail unit are established , and the numeral calculation result is verified through test and investigation.3-D simulation design is adopted.HBS process flow and process layout are optimized and designed.Combustion air two-stage high temperature preheating technology is designed and developed.Two sets of small size DCHBSs are adopted to preheat the combustion air to 520-600℃.With the precondition of BF gas combustion , the hot blast stove dome temperature can exceed 1 420 ℃. According to DCHBS technical features , reasonable refractory structure is designed.Effective technical measures are adopted to prevent hot blast stove shell intercrystalline stress corrosion.Hot blast stove hot pipe and lining system are optimized and designed.After blowing in , the blast temperature keeps increasing , and the monthly average blast temperature reaches 1 300℃ when burning single BF gas.ZHANG Fu-ming , MAO Qing-wu , MEI Cong-hua , LI Xin , HU Zu-rui ( Beijing Shougang International Engineering Technology Co Ltd , Beijing 100043 , China ) 2012Journal of Iron and Steel Research(International)2012,19,9:11
8湿法磷酸副产氟硅酸用于磷矿脱镁试验研究显示文摘对湿法磷酸副产氟硅酸和它与硫酸的混合酸用于磷矿脱镁进行了试验研究。优化了工艺技术路线、工艺控制条件。考察了所能达到的 Mg O脱除率、P2 O5回收率、脱镁酸耗等技术经济指标。为中试装置的设计提供依据。R & D Center of Yunnan Sanhuan Chemical Co.,Ltd. (Yunnan Sanhuan Chemical Co., Ltd, Kunming, Yunnan 650113, China) 2003磷肥与复肥2003,18,6:8
9Experimental and numerical studies on new multi-dimensional earthquake isolation and mitigation device:Horizontal properties显示文摘Earthquake is a complex multi-dimensional excitation. Counter-measures of such multi-dimensional excitation on many critical structures,such as long-span structures and high-rise buildings,must be taken into account to avert the structural failure. Many types of earthquake mitigation or isolation devices for mitigating earthquake-induced effects in the horizontal direction have been proposed and applied to real applications. However,study on multi-dimensional earthquake isolation and mitigation devices for structures has been received much less attention. In this paper,a new multi-dimensional earthquake isolation and mitigation device was developed and tested. Effects of excitation frequency and environmental temperature on horizontal properties of this device were considered. At the same time,fatigue properties of the device under different amplitude horizontal excitations were also studied experimentally. The equivalent standard solid model which can effectively describe the effect of frequency and temperature on the horizontal properties of the device was proposed and verified. From the experimental results,it may be concluded that the multi-dimensional earthquake isolation and mitigation device owns fine energy dissipation and fatigue resistance capabilities.XU ZhaoDong1, ZENG Xiao2, HUANG XingHuai1 & LU LiHeng1 1 RC&PC Key Laboratory of MOE, Southeast University, Nanjing 210096, China 2 Huaxin Past & Telecom Consulting and Designing Institute Co. Ltd, Hangzhou 310014, China 2010Science China(Technological Sciences)2010,53,10:7
10Research on Relationships Between Built Environment and Criminal Behavior in Parking Areas: A Case Study on Pudong New Area, ShanghaiMAO Yuanyuan, PhD Candidate, School of Architecture & Urban Planning, Tongji University, Shanghai, P. R. China. DAI Shenzhi, Professor, School of Architecture & Urban Planning, Tongji University, Shanghai, P. R. China. DENG Tian, China Overseas Property Group Co., Ltd (Eastern China), Shanghai, P. R. China. XU Bin, Off icer, Shanghai Municipal Public Security Bureau Pudong Branch, Shanghai, P. R. China. ZHU Wei, PhD, Eindhoven University of Technology, Eindhoven, the Netherlands. DONG Hengping, Postgraduate student, School of Architecture & Urban Planning, Tongji University, Shanghai, P. R. China. 2009China City Planning Review2009,18,2:7
11Photocatalytic degradation of coking wastewater by nanocrystalline (Fe,N) co-doped TiO_2 powders显示文摘The yellowish nitrogen and iron co-doped nanocrystalline titanium dioxide ((Fe,N) co-doped TiO2) powders have been prepared by hydrothermal method using TiOSO4 and CO(NH2)2 as starting materials.The grain size of the synthesized powders was estimated as 11 nm by Scherrer's method.The UV-Vis diffuse reflectance spectra indicated that the light absorption edge of the powders was red-shifted up to 605 nm.And the doped TiO2 powders exhibited good photocatalytic activities during the photo-degradation of coking wastewater under sunshine irradiation.The biotreatability of the coking wasterwater after photocatalytic degradation was improved greatly and it is more suitable to be further treated by biochemical method.LIU WenXiu1,LIU Qing1,LI XiuFang1,2,SONG YunTing1 & CAO WenBin1 1 Department of Inorganic Nonmetallic Materials,School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China 2 Tangshan Iron & Steel Co.,Ltd,Tangshan 063016,China 2010Science China(Technological Sciences)2010,53,6:7
12Reduction Behavior of Sinter Based on Top Gas Recycling-Oxygen Blast Furnace显示文摘In order to explore the behavior laws of sinter reduction in TGR-OBF ( top gas recycling-oxygen blast furnace ), reduction experiments of sinter have been conducted by thermal balance mass loss method with different atmospheres , temperatures and volume flows.The changes of RI ( reduction degree of Fe 2 O 3 ), RI′ ( reduction rate of Fe 2 O 3 ) and r ( reduction degree of FeO ) have been examined.The results show that the reduction of sinter was significantly improved under TGR-OBF atmosphere , and the RIand r were measured up to 98.2%and 97.8%at 900℃ respectively.With increasing of the reduction temperature , the reduction of sinter speeded up greatly , and the reduction time-duration shortened from 117min at 900 ℃ to 63min at 1 100 ℃.Moreover , the reduction of sinter enhanced with increasing of the reductive gas flow.When the flow increased from 10to 15L / min , the initial reduction rate of sinter increased from 2.47% / min to 3.73% / min.While increasing H2and CO contents in the reductive atmosphere , the reduction of sinter was promoted.Besides , H 2 influenced more evidently than CO to the reduction of sinter , especially in the later stage of the reduction process , for instance , the reduction of wustite will be improved enormously when increasing the H2content in the reductive atmosphere.LAN Rong-zong 1 , 2 , WANG Jing-song 1 , HAN Yi-hua 1 , SHE Xue-feng 1 , WANG Lin-tao 1 , XUE Qing-guo 1 ( 1.State Key Laboratory of Advanced Metallurgy , University of Science and Technology Beijing , Beijing 100083 , China 2.China Railway Materials Xiamen Steel Co Ltd , Xiamen 361008 , Fujian , China ) 2012Journal of Iron and Steel Research(International)2012,19,9:6
13Formation mechanism and model for sand lens reservoirs in the Jiyang Sub-basin,East China显示文摘The Bohai Bay basin comprises some very important and well documented subtle traps known in China, which have been the major exploration focus and have become a major petroleum play since the 1990s. However, recent exploration showed that the oil-bearing proper-ties of some sand lens reservoirs may vary significantly and the accumulation mechanisms for these lithological subtle traps are not well understood. Based on statistical analysis of oil-bearing properties for 123 sand lens reservoirs in the Jiyang Sub-basin and combined with detailed anatomy of typical sand lens reservoirs and NMR experiments, it has been shown that the structural and sedimentary factors, hydrocarbon generation and expulsion conditions of the sur-rounding source rocks, as well as the petrophysical properties of sand lens reservoirs are the main controlling factors for the formation of sand lens reservoirs. The formation of a sand lens reservoir depends on the interaction between the hydrocarbon accumulation driving force and the resistance force. The driving force is made up of the differential capillary pressure between sandstones and sources rocks and the hydrocarbon diffusion force, and as well as the hydro-carbon expansion force. The resistance force is the friction resistance force for hydrocarbons and water to move through the pore throats of the sand lens. The sedimentary environment, source rock condition and sand reservoir properties can change from unfavorable to favorable depend-ing on the combination of these factors. When these three factors all reach certain thresholds, the sand lens reservoirs may begin to be filled by hydrocarbons. When all of these conditions be-come favorable for the formation of sand lens reservoirs, the reservoir would have high oil satu-ration. This approach has been applied to evaluating the potential of petroleum accumulation in the sand lens reservoirs in the third member of the Neogene Shahejie Formation in the Jiyang Sub-basin.LI Pilong 1, PANG Xiongqi2,3, CHEN Dongxia2,3, ZHANG Shanwen1, JIN Zhijun4 & JIANG Zhenxue2,3 1. Shengli Oil Field Ltd, SINOPEC, Dongying 257051, China 2. University of Petroleum, Beijing 102249, China 3. Key Laboratory of Oil and Gas Accumulation, Ministry of Education, Beijing 102249, China 4. Research Institute of Petroleum Exploration and Exploitation, SINOPEC, Beijing 100083, China 2004Science China Earth Sciences2004,47,z2:6
14Deformation Uniformity of Cold-Rolled Q235 Steel Rebar by FEM in Bending and Rolling Processes显示文摘An analytic model based on ANSYS/LS-DYNA has been developed on the cold rolling process for Q235 steel rebar with 12 mm in diameter. The elastic-plastic finite element method (FEM) and the cold deformation resistance model of Q235 steel were adopted in this model. Deformation uniformity of the final product has been analyzed using this model. The results indicate that the uniformity of the final product is obtained only as the centerline of the bending rolls is vertical to the centerline of the driven roll and parallel to the centerline of the drive roll in the whole rolling process. Besides, the number of the bending rolls must even realize the continuous bending and reverse bending process. Also, the number of the bending rolls must match the deformation degree of the workpiece in the cold rolling process. The validity of this finite element model was verified by the size and distribution of grains from the billet to the rebar in a practical cold rolling process.SUI Feng-li1, CHEN Qi-wei1, ZHU Guo-hui1, LIU Bao-dong2 (1. Anhui Key Laboratory of Materials and Processing, School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002, Anhui, China 2. Dongyang Steel Making Co Ltd, Shenyang 110026, Liaoning, China) 2012Journal of Iron and Steel Research(International)2012,19,8:4
15Investigation of X-1P coating on magnetic head to enhance the stubility of head/disk interface显示文摘Stable lubrication is essential to slider/disk interface of computer hard disk drive. Inertlubricant perfluoropolyether (PFPE) on magnetic hard disk in computer is still prone to catalyticdecomposition by Al2O3, which is one of the materials in slider. A partial fluorinated hexaphenoxycyclotriphosphazene chemical, X-1 P, was analyzed to research on its function to reduce the cata-lytic decomposition of lubricant. The surface free energy of X-1 P coated on head surface was alsoinvestigated. Contact start-stop (CSS) tester was employed to investigate the reflow effective ofX-1 P on lubricant PFPE. Results indicate that thermal stability and reflow of lubricant will be im-proved in the presence of X-1 P on the slider.YANG Mingchu LUO Jianbin WEN Shizhu ZHANG Xiaoqing LI Yu I. Yagi TIAN Hong 1. State Key Laboratory of Tribology, Tsinghua University Beijing 100084, China 2. Material & Tribology Engineering Department, SAE Magnetics (H. K.) Ltd, Hong Kong, China 2001Science China Mathematics2001,44,S1:4
16Carbon Segregation of Bearing Steel Concasting Billet显示文摘The formation mechanism of 'white band' and central carbon segregation of high-carbon Cr bearing steel concasting billets are discussed in this paper. The maximum oxygen content in the steel produced by concasting process was 13 ?10-6 with an average oxygen content of 9.3?10-6. Comparison of metallurgical quality and fatigue property between the concasting steel (CC) and ingot casting steel (IC) showed that the carbon segregation (C/C0) in former steel was 0.921.10 and its fatigue life was equal to that of the latter steel.Deguang ZHOU, Jie FU and Ping WANG (University of Science and Technology Beijing, Beijing 100083, China) Junhao XU, Yaqing XIE and Zheng LI (Daye Special Steel Co. Ltd, Huangshi 435001, China) 2000Journal of Materials Science & Technology2000,16,3:4
17Excellent Heat Affected Zone Toughness Technology Improved by Use of Strong Deoxidizers显示文摘Excellent Heat Affected Zone Toughness Technology Improved by use of Strong Deoxidizers (ETISD Technology) has been developed by Baosteel. When deoxidation of molten steel is conducted at the precisely controlled oxygen concentrations, the formation of the micro-meter inclusions and the nano-meter precipitates in the steel plate can be effectively controlled. During the welding process with high-heat input, the formation of acicular ferrite can be selectively promoted with the aid of micro-meter inclusions; the growth of γ grain can also be selectively restrained by the pinning effect of nano-meter precipitates. After welding with high-heat input of 400 kJ/cm, excellent heat affected zone toughness can be obtained for the steel plates with both of the above microstructures, and the average absorbed energy is greater than 200 J for V notch Charpy impact test at -20℃ .YANG Jian, ZHU Kai, WANG Rui-zhi, SHEN Jian-guo (Metallurgical Process Department, Research Institute, Baoshan Iron and Steel Co Ltd, Shanghai 201900, China) 2011Journal of Iron and Steel Research(International)2011,18,S2:4
18Chemistry Design of B-Containing Ultra-Heavy Plate Steels Aided by Thermo-Calc Calculation显示文摘Effect of N-bonding elements on dissolution and precipitation of B in micro B-treated ultra-heavy plate steels has been investigated,utilizing Thermo-Calc thermo-dynamic software and experimental test.The calculation results show that Titanium or excessive Aluminum content is effective to bond Nitrogen,preventing BN from forming and thus keeping boron in solid solution in austenite,while Vanadium is not.The experiment has also revealed that slight amount of solution Boron by addition of Ti or a little excessive Aluminum is helpful to improve hardenability of the steels.PAN Tao 1,WANG Xiao-yong 1,WANG Hua 2,LI Yun 2,SU Hang 1,YANG Cai-fu 1 (1.Division of structural materials,Central Iron and Steel Research Institute,Beijing 100081,China 2.Anshan Iron and Steel Co Ltd,Anshan 114001,Liaoning,China) 2011Journal of Iron and Steel Research(International)2011,18,S1:3
19Flatness and Profile Integration Control Model for Tandem Cold Mills显示文摘Using the effective matrix methods of flatness and profile control synthetically, the flatness and profile integration control scheme for tandem cold mills is built in order to increase flatness and profile control precision of tandem cold mills. Corresponding control strategies are adopted for various control objectives of different stands and the coordination control strategies of various stands are given, which makes the on-line flatness control cooperate with on-line profile control and implements the parallel control of different stands. According to the measured flatness and profile data of some 1550 mm tandem cold mills, the control scheme is verified and the result indicates that the scheme has high flatness and profile control precision with steady and reliable control process. A new way and method is supplied for researching shape control of tandem cold mills.SHAN Xiu-ying1,2,3, LIU Hong-min1,2, JIA Chun-yu1,2, SUN Jian-liang1,2 (1. Engineering Research Center of Rolling Equipment and Complete Technology of Ministry of Education, Yanshan University, Qinhuangdao 066004, Hebei, China 2. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, Hebei, China 3. Hot Tandem Rolling Factory, Jinan Iron and Steel Co Ltd, Jinan 250101, Shandong, China) 2012Journal of Iron and Steel Research(International)2012,19,3:3
20Effect of Initial Microstructure on Warm Deformation Behavior of 45 Steel显示文摘In order to investigate the effect of initial microstructure on warm deformation behavior, some specimens of 45 steel were annealed and some quenched. Then the specimens were isothermally compressed on a Gleeble 3500 machine. The deformation temperature range was 550 to 700 ℃ and the strain rate range was 0.001 to 0.1 s-1. An optical microscope (OM) and a transmission electron microscope (TEM) were used to study the microstructures. The results show that the microstructure of annealed specimens is ferrite and pearlite and that of quenched specimens is martensite. The flow stress of quenched specimens is higher than that of annealed ones at 550 ℃ when strain rates are greater than 0.001 s-1. However, at 600 to 700 ℃ and strain rate of 0.001 s-1, the whole flow curves of quenched specimens are below that of annealed ones. Under the rest conditions, the flow stress of quenched specimens is higher at the beginning of compression and then the opposite is true after the strain is greater than a critical value. The microstructure examination proves that the tempering and dynamic recrystallization easily occur in the specimens with martensite during warm compression, which results in the above phenomena.ZHAO Xin1, YANG Xiao-ling2, JING Tian-fu3 (1. The Sixth Department, Zhengzhou Institute of Aeronautics, Zhengzhou 450015, Henan, China 2. Zhengzhou Zhongxing Basic Constructions Development Co Ltd, Zhengzhou 450015, Henan, China 3. State Key Laboratory of Metastable Materials Science and Technology, Qinhuangdao 066004, Hebei, China) 2012Journal of Iron and Steel Research(International)2012,19,8:3
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