2010年, 第17卷, 第10期　刊出日期：2010-10-15

  

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工艺
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  Numerical and Experimental Investigation on Heat Propagation through a Composite Sinter Bed with Non-uniform Voidage. Part 1 : Mathematical Model and Its Experimental Verification.

  Sergey V.Komarov

  中国钢铁期刊网. 2010, 17(10): 1-0.

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  Gas-particle Flow and Combustion Characteristics of Pulverized Coal Injection in Blast Furnace Raceway

  ZHANG Shengfu;BAI Chenguang;WEN Liangying;et al

  中国钢铁期刊网. 2010, 17(10): 8-8.

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  Application of Modified QuasiRegular Solution Model to Binary Metallurgical Molten Slag Systems

  HOU Yanqing;XIE Gang;TAO Dongping;et al

  中国钢铁期刊网. 2010, 17(10): 13-13.

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  Modified quasi-regular solution model has been got based on the sub-regular solution model and quasi-regular solution model in this article. The mixed energy parameter can be denoted a function of concentration and temperature. The three parameters of this model are fitted by the computer-assisted analysis based on the experiment data of activity at two different temperatures. Seven binary molten slag systems in the whole concentration are calculated with the application of the model and the average relative error is within 10%. That shows that the calculated result is agreement with the experiment data. Ten binary slag systems presenting saturation concentration are also calculated, but the average relative error is bigger. So the calculated result is not good agreement with the experiment data. But the calculated result is superior to regular solution model, sub-regular solution model and quasi-regular solution model.
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  Effect of B2O3 on Melting Temperature of CaO-Based Ladle Refining Slag

  WANG Hongming;LI Guirong;LI Bo;et al

  中国钢铁期刊网. 2010, 17(10): 18-22.

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  B2O3 is selected as fluxing agent of CaO-based ladle refining slag to decrease the melting temperature as well as to improve the speed of slag forming and the refining efficiency. The effects of B2O3 on the melting temperature of two series of refining slags including the low basicity slags (the mass ratio of CaO/SiO2 is 3~4) and the high basicity slags (the mass ratio of CaO/SiO2 is 5~8.75) were investigated. The slag melting temperature was measured using the hemisphere method. The results indicate that the fluxing action of B2O3 is better than that of CaF2 and Al2O3. For the CaO-based refining slag with low basicity, the melting temperature is decreased effectively when B2O3 is used to substitute for equal mass of CaF2, Al2O3 and SiO2, respectively. For the CaO-based refining slag with high basicity, when CaF2 is substituted with B2O3, the melting temperature can be decreased remarkably. Especially, when the mass ratios of CaO/Al2O3 and CaO/SiO2 are in range of 1.1~4.0 and 5.25~8.0, respectively, the slag melting temperature is lower than 1300℃. Therefore, the B2O3-containing refining slags with high ratios of CaO/Al2O3 and CaO/SiO2 have ultralow melting temperature. As a result, not only the slag forming speed but also the capabilities of desulfurizing, dephosphorizing and absorbing deoxidation products are expected to be improved.
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  Electro-Hydraulic Servo Control System Based On Novel Generic Model Control Method

  DAI Yongbin;YANG Weidong;WANG Shaofu;et al

  中国钢铁期刊网. 2010, 17(10): 23-27.

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  This paper presents a new electro-hydraulic servo control method. This method introduces model predictive into generic model control (GMC). By receding optimization and makes feed-back correction, GMC performance is improved. Using improved weighted least square Support Vector Machines (WLS-SVM) to forecast and compensate the future sequence errors, the system’s precision and robust ness were increased. It elementary solved the systems delay, nonlinearity and time variability. The GMC based on improved WLS-SVM are applied to electro-hydraulic servo control system in hot mill. The result of a numerical simulation experiment shows the feasibility and effectiveness of this algorithm
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  Effect of Laminar Cooling on Phase Transformation Evolution in Hot Rolling Process

  NING Linxin;YANG Daijun;J Lin;et al

  中国钢铁期刊网. 2010, 17(10): 28-32.

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  In the hot rolling processes, it always uses the laminar cooling system to control the cooling of plate and get the microstructure of different constitution. To investigate the effect of temperature variation due to the cooling pattern, rolling speed and thickness of plate on the microstructure evolution, a thermal-mechanical coupled FE model has been established. A set of constitutive equations of phase transformation is implemented into the commercial FE solver MARC through the user defined subroutine CRPLAW, and the temperature field is calculated by another user defined subroutine FILM. The effect of cooling pattern, rolling speed and thickness of plate on the temperature variation is numerically studied. Furthermore, the effect of temperature variation on the evolution of each phase transformation is investigated for various cooling pattern.
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  Specific Energy Consumption Analysis Model and Its Application in Typical Steel Manufacturing Process

  SUN Wenqiang;CAI Jiuju;DU Tao;et al

  中国钢铁期刊网. 2010, 17(10): 33-37.

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  manufacturing process (SMP) were studied. Firstly, a process division of a typical SMP in question was conducted with the theory of SEC analysis. Then, an exergy analysis model of a subsystem consisting of several parallel processes and a SEC analysis model of SMP were developed. And finally, based on the analysis models, the SEC of SMP was analyzed by means of the statistical significance. The results show that the SEC of typical SMP is comprised of the theoretical minimum SEC and the additional SEC derived from the irreversibility; and the SMP has a theoretical minimum SEC of 0.230 ton c.e. (coal equivalent) per ton steel and an additional SEC of 0.659 ton c.e. per ton steel, which account for 25.88% and 74.12% of the actual SEC, respectively.
材料
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  Heredity Characteristic From Hot Rolled Microstructure to Annealed Microstructure in High Strength TRIP Steels

  XIONG Ziliu;CAI Qingwu;JIANG Haitao

  中国钢铁期刊网. 2010, 17(10): 38-44.

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  The influence of hot-rolled process on microstructure in TRIP steel and the heredity characteristic from the hot-rolled microstructure to annealed microstructure are investigated. The results show there are two kind of hot-rolled microstructures under different coiling temperatures. One is composed of coarse grains of ferrite, pearlite and bainite, and the other is composed of small grains of ferrite, bainite and austenite. After annealing, the first kind of hot-rolled microstructure is greatly refined, and volume fraction, carbon content of austenite increase significantly. However, it have little changes in grain size, volume fraction and carbon content of austenite after the second kind of hot-rolled sheet is annealed. There are also differences in distribution of retained austenite between the two annealed microstructures observed by EBSD and TEM technology. Retained austenite in the first annealed microstructure distributes mainly inside of the polygonal ferrite in the form of spot, only little retained austenite on bainte ferrite boundary, however retained austenite in the second annealing microstructure allocates several places, such as inside of polygonal ferrite, on polygonal ferrite boundary, on bainte ferrite boundary.
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  Hot Working of High Nitrogen Austenitic Stainless Steel

  LANG Yuping;ZHOU Yong;RONG Fan;et al

  中国钢铁期刊网. 2010, 17(10): 45-49.

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  with hot rolling in laboratory and Gleeble hot simulator, the hot working of a hign nitrogen austenitic stainless steel (HNASS) has been researched. The results show that HNASS occurs dynamic recovery (DRV) and dynamic recrystallization (DRX) during hot working. All of them have well-defined stress peaks in flow curves at different conditions.During hot rolling experiment with temperature from 950℃ to 1050 ℃，test material did not take place recrystallization phenomenon until the deformation is up to 40%. Recrystallization influences remarkably the strength and ductility of material. Results show that test HNASS processes best strength combination with ductility.According to the curve of , the DRX critical strain of test material is determined. Also we calculate the activation energy of hot working with value of 746.5kJ/mol and attain the equation of hot working.
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  Ultrafine Grained HSLA Steels for Cold Forming

  R González;J O García;M A Barbés;et al

  中国钢铁期刊网. 2010, 17(10): 50-56.

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  This research shows, through the analysis of three steels that comply with the EN 10149-2 Euronorm, examples of ultrafine grained (or ultrafine ferrite) ferrous alloys, with ASTM grain sizes close to 14 (2 3 m). These steels are microalloyed with Ti-Nb and have been produced by advanced hot rolling controlled techniques in the factories of ArcelorMittal de Avilés (Asturias, Spain) and are mostly used in automotive and construction applications. By comparison, other techniques to obtain ultrafine grained steels are mentioned, though they have not yet reached the industrial level and are produced in laboratories due to the fact that their mechanical properties (low strain hardening coefficient "n") don't allow cold working operations such as bending, stretching nor drawing.
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  Tempering Behavior of 45Cr-2W-0.25V Steel

  Mohsen Asadi Asadabad

  中国钢铁期刊网. 2010, 17(10): 57-62.

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  In this research the tempering behavior of a Cr-W-V steel was investigated. This new alloy with the composition of Fe-4.5Cr-2W-0.25V-0.1C was austenitized at 1000°C for 30 min and tempered at 500°C to 700°C for different times up to 100h. An OM analysis of the microstructure of air cooled and water quenched specimens before tempering showed that although in both conditions fully martensitic matrix formed, finer structure had formed in the water quenched specimens. The XRD and TEM results showed that the most stable carbides formed during tempering of the steel were M23C6 and M7C3, respectively. Other carbides such as M3C and M2C, formed in the first stages of tempering, and stable MC were also observed. The results showed that when the tempering time, temperature and cooling rate were increased, weight percent of extracted precipitates was increased. In addition, the formation rate of the stable carbides such as M23C6 and dissolution rate of the metastable carbides such as M3C and M2C were increased. The hardness results was revealed that tempering at 600°C and 700°C result in gradual decrease in hardness, but didn't observed significant changes in hardness at 500°C even for long tempering times.
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  Mechanical Properties and Microstructure of X120 Grade High Strength Pipeline Steel

  ZHANG Jiming;SUN Weihua;SUN Hao

  中国钢铁期刊网. 2010, 17(10): 63-67.

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  A new ultrahigh strength pipeline steel with high yield strength and high impact toughness was fabricated in this work, and mechanical properties and microstructure of the steel were investigated in this paper. The steel exhibited outstanding mechanical properties with yield strength levels of up to 951MPa and Tensile strength levels up to 1023MPa. The sharp notch-toughness with absorbed energy values of 227J/cm2 at Temperatures of -30℃ and %shear of up to 95% in drop weight tear test (DWTT) at temperatures of -20℃ were achieved. It was found that microstructure of the steel comprises a majority of low carbon lath bainite with different sublaths and sub-sublaths, meanwhile there is a high density of dislocation between laths and the dispersed film-like martensite-austenite (M-A) constituents. Most of the precipitates in this steel are duplex type containing Nb and Ti with characterized morphology of cap. The precipitation size is a few to a few tens nanometers.
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  Microstructure, Tensile and Impact Toughness Properties of Friction Stir Welded Mild Steel

  A.K.Lakshminarayanan

  中国钢铁期刊网. 2010, 17(10): 68-74.

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  Microstructure, tensile and impact toughness properties and fracture location of friction stir welded AISI 1018 mild steel are revealed in this paper. The 5 mm thick AISI 1018 mild steel plates were friction stir welded with tool rotational speed of 1000 rpm and welding speed of 50 mm/min with tungsten base alloy tool. Tensile strength of stir zone is higher (8%) when compared to the base metal. This may be due to the formation of finer grains in the weld nugget region under the stirring action of the rotating tool. The ductility and impact toughness of the joints are decreased compared to the base metal and this is due to the inclusion of tungsten particles in the weld region.
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  Effects of Nanometer Carbon Black on Performance of Low-Carbon MgO-C Composites

  LIU Bo;SUN Jialin;TANG Guangsheng;et al

  中国钢铁期刊网. 2010, 17(10): 75-78.

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  Abstract: The low-carbon magnesia–carbon (MgO-C) composites containing 3% (mass fraction, the same below) carbon were prepared by adding various types of carbon black (CB). The mechanical properties, oxidation resistance at 1100℃ in oxidizing atmosphere, and thermal shock resistance after 5 times dipping in 1600 ℃ molten-steel of the low-carbon composite samples were investigated, compared with a commercial high-carbon MgO-C composite containing 16% carbon. The results show that the mechanical properties, oxidation resistance and thermal shock resistance of the low-carbon samples improve with the decrease of CB particle size. Thermal shock resistance of the low-carbon sample containing nanometer CB N220 is obviously better than other low -carbon samples, and reaches the level of the high-carbon samples.