2010年, 第17卷, 第8期　刊出日期：2010-08-15

  

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工艺
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  Calcinations of slags for electroslag remelting

  DONG Yan-wu;JIANG Zhou-hua;XIAO Zhi-xin;et al

  中国钢铁期刊网. 2010, 17(8): 1-5.

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  Mathematic Model of SEN Clogging During Continuous Casting of Steel

  WU Su-zhou;ZHANG Jiong-ming;LI ZHi-zheng

  中国钢铁期刊网. 2010, 17(8): 6-6.

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  The SEN clogging is a long term issue for all the steelmakers. In the current study, the kinetics of SEN clogging during steel continuous casting was established. The dynamic build-up of alumina inclusions to the lining refractory of SEN was analyzed. The fluid flow and inclusions motion are calculated by means of mathematic model. Effect of diameters of inclusions, roughness of nozzle, diameter of nozzle and casting speed on the entrapment probability are estimated.
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  Effect of Linear Electromagnetic Stirring on Behavior of Liquid Metal and Rate of Slag-Metal Interfacial Reactions

  LI Yan-hua. SU Zhi-jian;HE Ji-cheng

  中国钢铁期刊网. 2010, 17(8): 10-14.

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  Against the background of actual metallurgical equipment with linear electromagnetic stirring system，the study measures and analyzes the internal flow, the free surface shape and level fluctuation of liquid metal exposed to linear electromagnetic stirring with Doppler ultrasound velocimetry and laser liquid level apparatus respectively, and then desulphurization process with or without imposition of linear electromagnetic stirring is studied experimentally. The change of sulfur content of hot metal with respect to time is obtained, and the volume mass transfer coefficients corresponding to different stirring current is determined finally. The result shows that linear electromagnetic stirring can not only effectively promote the internal flow, but also effectively increase the level fluctuation so as to significantly improve the kinetic condition of liquid metal. The internal flow and level fluctuation of the liquid metal would increase in line with the increase of electromagnetic stirring intensity. The desulphurization experiments show that the linear electromagnetic stirring can significantly promote the desulphurization process of hot metal, and the technology has wide application prospect in promoting various slag-metal reaction.
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  Numerical Simulation of Influence of Casting Speed Variation on Surface Fluctuation of the Molten Steel in Mold

  ZHANG Qiao-ying;WANG Xin-hua

  中国钢铁期刊网. 2010, 17(8): 15-15.

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  The influences of casting speed variation on surface fluctuation of the molten steel of mold during continuous casting were investigated with numerical simulation method. It was found that, when the casting speed was evenly decreased from 1.4m/min to 0.6m/min, increases of the surface fluctuation of the molten steel of mold were observed only on time that was at the start of casting speed change. While, in experiment of increasing casting speed evenly from 0.6m/min to 1.4m/min, increases of the surface fluctuation of the molten steel of mold were observed only at the time when the casting speed was stopped to increase after it had been increased to 1.4m/min. For surface fluctuation of the molten steel of mold which was produced during the casting speed evenly increasing or decreasing period and at the time when increasing or decreasing the casting speed at low casting speed level (0.6m/min), the influence of casting speed change was very small. In addition, it was found that, at high casting speed level (1.4m/min), even a little change of casting speed could result in remarkable increase of the surface fluctuation. Thus, at high casting speed, changing casting speed should be avoided or using much slower speed changing rate.
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  Industrial Research on Broadening of Slab in Continuous Casting Process

  FU Jian-xun;LI Jing-she

  中国钢铁期刊网. 2010, 17(8): 20-20.

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  The broadening of slab was investigated on the basis of several industrial manufactures of continuous casting. The results show that slab broadening commonly exists in the process of continuous casting. It is found that there are few reports on it until now. In order to find out the reasons of slab broadening, we checked the effect of change of mold size, excepting technological parameters, conditions of soft reduction, and contraction of roll gap on slab broadening. Our examinations exclude the possibility of change of mold size, excepting technological parameters to be the causes of broadening of slab. The broadening of slab probably results from the static pressure of molten steel and the force from driving rolls. At the same time, online observations on three kinds of steel in the process of continuous casting reveal that the average objective ratio of slab broadening ranges from 1.27 % to 3.00 %, and even arrives at 4.4 %. In addition, the width of mold and formulas of calculating the broadening of slab was deduced.
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  Finite Element Simulation of Cold-Rolling Process of Shaped Steel Tube for Driving Shaft

  SHUAI Mei-rong;LIU Shao-bo;GAO Cong-min;et al

  中国钢铁期刊网. 2010, 17(8): 25-25.

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  Based on the deformation characteristics of Y-type mill, this paper proposes a finite element model for dynamically simulating the formation process of shaped steel tube for driving shaft. The distributions of stress and strain were obtained from the simulation. The outer diameter and transverse wall thickness were also analyzed quantitatively. Experiment was done on Y-type mill. A comparison between simulation results and experiment results shows that the simulating results of shaped steel tube are in good agreement with the on-site data. The model could provide the basis for theoretical research and engineering applications of shaped steel tube rolling process.
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  Property Prediction Using Hierarchical Regression Model Based on Calibration

  TAN Shuai;ChEB wei-dong; WANG Fu-li;et al

  中国钢铁期刊网. 2010, 17(8): 30-30.

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  Abstract：In this paper, a multiphase orthogonal signal correction modeling and hierarchical statistical analysis strategy is developed for the improvement of process understanding and quality prediction. According to background, hierarchical PLS is used to build regression model of process variables and quality variables. This blocking leads to two model levels: the upper level where the relationships between blocks are modeled and the lower level showing the details of each block. Furthermore, in each lower model, O2-PLS is used to remove the structured noise in both X and Y, which is not contributed to prediction model. The corresponding loading vectors provide good interpretation of the covarying part in X and Y. Simulation of the continuous annealing line demonstrates the efficiency of the proposed algorithm for better process understanding and quality interpretation.
材料
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  Solubility Product for CuS and Cu2S in Iron

  QI Hai-quan;YONG Qi-long

  中国钢铁期刊网. 2010, 17(8): 36-38.

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  根据CuS 和Cu2S的形成能以及Cu 和S在铁素体与奥氏体中的固溶度，得到了CuS和Cu2S在铁素体和奥氏体中的固溶度积，分别为log[Cu][S]=6.15-5643.78/T , log[Cu][S]=6.15-5643.78/T,log[Cu][S]=6.007-5620.3/T (CuS分别在铁素体和奥氏体中), log[Cu]2[S]=6.62-9693.75/T and[Cu]2[S]=6.143-9048.66/T (Cu2S分别在铁素体和奥氏体中），这些结果可应用于相关的研究工作。
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  Effect of Nb to Austenite Recrystallization in High Temperature Deformation Processing

  JIAO Duo-tian;CAI Qing-wu;WU Hui-bin;et al

  中国钢铁期刊网. 2010, 17(8): 39-44.

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  By analysing the stepped test pieces with optical microscope, the influence of the Technological parameters including rolling temperature and reduction amount on the Austenitic recrystallization fraction of Nb content of 0.08％ steel deformed in high temperature processing was studied, and the deformed austenite recrystallization figures of the test steel were obtained. The result indicates when the reduction amount is 60%, the critical temperature of complete recrystallization is 1070℃ and the borderline temperature of non recrystallization is 900℃. In contrast with general HSLA steel, the recrystallization and non recrystallization temperatures are respectively 120℃ and 100℃ higher so the steel contenting high Nb has better hot processing performance because Nb has great function of holding back recrystallization.
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  Experimental Study and Kinetic Calculation on Migration of γ/α Interface Boundary During High Temperature Aging in 2205 Duplex Stainless Steel

  LIU Xiong;DING Xing-ping;HE Yan-lin;et al

  中国钢铁期刊网. 2010, 17(8): 45-45.

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  Aging treatments at the temperature range of 1000-1200 ℃ for different time intervals (10, 30, 60min) in a solution-treated 2205 duplex stainless steel(DSS) are carried out respectively. The migration of γ/α interface boundary after different ageing treatments is measured by optical metallography and calculated by DICTRA software. The agreement of the calculation and experimental results is satisfied. The migration of γ/α interface boundary with increased keeping time depends on the chemical potential of chromium in each phase. At the aging temperature of 1100℃, the back diffusion effect of chromium results in the opposite direction migration of γ/α interface, therefore, the ferrite volume fraction gets lower at first and then gets higher after 1800s diffusion
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  Influence of Tempering Process on Mechanical Properties of 00Cr13Ni4Mo Supermartensitic Stainless Steel

  Zou De-ning;HAN Ying;ZHANG Wei;et al

  中国钢铁期刊网. 2010, 17(8): 50-54.

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  Supermartensitic stainless steel (SMSS) is a new-style material has been introduced into the oil and gas industries to substitute more expensive duplex stainless steel for deep/ultra-deep well tubing applications. For improving mechanical properties of the certain chemical composition steel, a balance between strength and toughness must be achieved by controlling heat treatment. In this paper, the influence of tempering process on microstructure and mechanical properties of 00Cr13Ni4Mo SMSS was investigated. 600°C was chosen as the optimized tempering temperature from the quenching and different temperature tempering tests. The samples were kept at 600°C for 3h, 6h, 8h, 10h and 12h respectively, followed by air cooling. Scanning electron microscopy and X-ray diffraction examinations were conducted to analyze the microstructural evolutions. It revealed that the superior mechanical properties were achieved with 1040°C quenching (kept 0.5h +water cooling) and 600°C tempering (kept 3h +air cooling). Increasing isothermal tempering time could improve the toughness notably. It was considered that the property was correlated with the microstructure of tempered lath martensite and retained austenite. The more content of retained austenite, the higher toughness of the SMSS.
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  Hot Deformation Behavior of V-microalloyed Steel

  REN An-chao;JI Yu;ZHOU Gui-feng;et al

  中国钢铁期刊网. 2010, 17(8): 55-60.

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  The expansion curves of continuous cooling transformation at different cooling rates was determined for U75V rail steel by THERMECMASTOR- Z thermal simulator，and continuous cooling transformation curve was obtained.The influedce of cooling rate on microstructure and hardness was studied.On the other hand，the softening behavior of isothermal deforming at austenite area 850～1000℃ within interval of passes has been also studied by double-pass compression test.The results show that the product of austenite transformation was pearlite when the cooling rate was lower than 10℃.Troostite and martensite were gained at the cooling rate of 10℃•s-1. Only martensite was received when the cooling rate was in the range of 10～ 50℃•s-1.the hardness of steel increased with the increase of cooling rate.Results also indicated that 30% deformation and 3S-1 deforming rate，as deformation temperature ≥1000℃，relaxation time for performing recrystallization was≤100s，and as deformation temperature≤880 ℃，it was difficult even extending relaxation time to put forward recrystallization of steel.
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  Static Recrystallization Kinetics Model after Hot Deformation of Low-alloy Steel Q345B

  MA Bo; PENG Yan;JIA Bin;et al

  中国钢铁期刊网. 2010, 17(8): 61-66.

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  The static recrystallization behavior of low-alloy steel Q345B during double-pass hot compression deformation tests was investigated in the temperature range of 900-1000℃, the true strain range of 0.15-0.25 and the interpass time range of 0.5-50s on Gleeble-3500 thermo-simulation machine. The results show that static recrystallization during the interpass time is observed. As the deformation temperature and strain increase, softening caused by static recrystallization is obvious. According to analyzing and calculating the data of thermo-simulation, the static recrystallization activation energy was obtained and static recrystallization kinetics model was set up. Finally, the error analysis of static recrystallization kinetics model proved that the model had good accuracy. Therefore, this model has a certain reference, providing a theoretical basis for SRX, and contributing to the development of multipass hot rolling process, in order to control the rolling process more accurately.
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  Design for Isothermal Forging of Ti-46.5Al-2.5V-1.0Cr-0.3Ni Alloy

  SI Jia-yong;HAN Peng-biao;Z HANG Ji

  中国钢铁期刊网. 2010, 17(8): 67-73.

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  Abstract: The three-dimensional finite element code was utilized to investigate the isothermal forging of Ti-46.5Al-2.5V-1.0Cr-0.3Ni (at.%). The partition of height reduction, effective strain and damage during the forging were analyzed. And the experiment was employed to verify the simulation results. The results show that severe plastic deformation can improve the homogeneity of the deformed microstructure and the higher accumulative height reduction can be achieved through two-step forging. With the isothermal forging of 60%+62.5% (total 85%), the entire forged pancake can acquire refined microstructure and expand the uniform flow zone to almost the entire volume without generating strain-induced defects or cracking.
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  Effect of NiCl2-Base Fluxes on Interfacial Layer Formation of Hot-Dip Galvanized Steels

  Yuttanant Boonyongmaneerat;Kanokwan Saengkiettiyut;et al

  中国钢铁期刊网. 2010, 17(8): 74-78.

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  While the thick growth of intermediate phase layers generally benefits the corrosion resistance of galvanized steels, it is unfavourable from the standpoints of mechanical integrity and economics. The present study investigates the role of nickel chloride-base fluxes, in relation to the typical zinc-ammonium chloride flux, in the reduction of galvanized coatings' thickness and the effect on coatings' morphology and compositions. The investigation of pretreated galvanized steel specimens hot-dipped for various durations has verified that nickel chloride fluxes influence the growth rate of the zeta interlayer. This results in the overall-reduction of the coating thickness by as much as two times compared to those prepared with the conventional flux. Nickel from the fluxes gradually diffuse away from the substrate's surface, and hence the initial concentration of the nickel salts along with the hot-dip duration need to be controlled appropriately for effective use of nickel chloride-base fluxes in the galvanizing process.