2007年, 第14卷, 第4期　刊出日期：2007-08-15

  

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Metallurgy and Metal Working
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  Monitoring Method for Blast Furnace Wall With Copper Staves

  CHENG Susen;QIAN Liang;ZHAO Hongbo

  中国钢铁期刊网. 2007, 14(4): 1-0.

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  A monitoring method that has been designed for the first time for blast furnace wall with copper staves manufactured in China was introduced. Combining the method of “inverse problem” and the concept “noninverse problem”, the monitoring program for blast furnace wall with copper staves has been realized, which can be used to calculate online the accretion thickness and temperature of hot surface of copper staves after obtaining the values of thermocouples of copper staves. The accretion state obtained in the actual investigation has proved that the result of the program is correct. The monitoring program shows that the accretion would easily fluctuate when the accretion layer is extremely thick or thin, thereby the stable and smooth operation of the blast furnace is hindered. By maintaining appropriate accretion thickness, both long campaigns and high productivity of the blast furnace can be achieved; furthermore, it can also optimize the operation of blast furnace and maximize its production. Approximately 30-50 mm in thickness of accretion layer is maintained on the wall of Shougang blast furnace 2, which can meet the requirement for obtaining both long campaign and high productivity.
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  Perturbation Solutions for Thermal Process of Honeycomb Regenerator

  AI Yuanfang;MEI Chi;HUANG Guodong;JIANG Shaojian

  中国钢铁期刊网. 2007, 14(4): 6-0.

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  A parameter perturbation for the unsteadystate heattransfer characteristics of honeycomb regenerator is presented. It is limited to the cases where the storage matrix has a small wall thickness so that no temperature variation in the matrix perpendicular to the flow direction is considered. Starting from a twophase transient thermal model for the gas and storage matrix, an approximate solution for regenerator heat transfer process is derived using the multiplescale method for the limiting case where the longitudinal heat conduction of solid matrix is far less than the convective heat transfer between the gas and the solid. The regenerator temperature profiles are expressed as Taylor series of the coefficient of solid heat conduction item in the model. The analytical validity is shown by comparing the perturbation solution with the experiment and the numerical solution. The results show that it is possible for the perturbation to improve the effectiveness and economics of thermal research on regenerators.
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  SelfLearning and Its Application to Laminar Cooling Model of Hot Rolled Strip

  GONG Dianyao;XU Jianzhong;PENG Lianggui;WANG Guodong;LIU Xianghua

  中国钢铁期刊网. 2007, 14(4): 11-0.

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  The mathematical model for online controlling hot rolled steel cooling on runout table (ROT for abbreviation) was analyzed, and water cooling is found to be the main cooling mode for hot rolled steel. The calculation of the drop in strip temperature by both water cooling and air cooling is summed up to obtain the change of heat transfer coefficient. It is found that the learning coefficient of heat transfer coefficient is the kernel coefficient of coiler temperature control (CTC) model tuning. To decrease the deviation between the calculated steel temperature and the measured one at coiler entrance, a laminar cooling control selflearning strategy is used. Using the data acquired in the field, the results of the selflearning model used in the field were analyzed. The analyzed results show that the selflearning function is effective.
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  Forward and Backward Slip Models in MAS Rolling Process and Its OnLine Application

  HU Xianlei;JIAO Zhijie;HE Chunyu;LIU Xianghua;WANG Guodong

  中国钢铁期刊网. 2007, 14(4): 15-0.

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  Based on the MAS rolling process in plate mill, the mathematical models of forward and backward slips of the wedges at plate head and tail were derived. According to the new model, the difference between the forward slip of the wedge and that of the normal part of the plate is obviously very small. The deviation is less than 25% in general. Thus, in actual application, the forward slip of normal part of the plate can be used to calculate the length of rolled plate instead of the derived model. The rationality of this simplified method was confirmed with the application in Shougang 3 500 mm plate mill. The test results showed that the wedges of plate head and tail are symmetrical. The plate width deviation is greatly decreased by using the MAS method.
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  Derivation of Simplified Models of Plan View Pattern Control Function for Plate Mill

  JIAO Zhijie;HU Xianlei;ZHAO Zhong;LIU Xianghua;WANG Guodong

  中国钢铁期刊网. 2007, 14(4): 20-0.

  摘要 ( )   可视化   收藏

  The plan view pattern control theoretical models were simplified. Under the condition of constant volume for the plan view pattern compensation, the relation between the thickness and the length can be simplified to the linearity in the segment for the plan view pattern control function. The compensation volume can be dispersed for easy calculation. By comparing the model calculation result with the actual result, it was concluded that the simplified model can be used for the online control process.
Material
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  UltraPure Ferritic Stainless Steels—Grade, Refining Operation, and Application

  YOU Xiangmi;JIANG Zhouhua;LI Huabing

  中国钢铁期刊网. 2007, 14(4): 24-0.

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  The grades of ultrapure ferritic stainless steels, especially the grades used in automobile exhaust system, were reviewed. The dependence of properties on alloying elements, the refining facilities, and the mechanism of the reactions in steel melts were described in detail. Vacuum, strong stirring, and powder injection proved to be effective technologies in the melting of ultrapure ferritic stainless steels. The application of the ferritic grades was also briefly introduced.
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  Effect of Microstructure of Cementite on Interphase Stress State in Carbon Steel

  CHE Lei;GOTOH Masahide;HORIMOTO Yoshiaki;HIROSE Yukio

  中国钢铁期刊网. 2007, 14(4): 31-0.

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  The experiments related to stress states of ferrite and cementite in carbon steels were carried out including in situ fourpoint bending and tensile test by Xray diffraction technique. Stresses in the cementite phase can be measured by conventional Xray diffraction instrument after a specific treatment on the specimen surface. In order to estimate the stress states in two phases, the Xray elastic constants of two phases in singlephase state (PXEC) are determined by the experimental Xray elastic constants of them in composite state (CXEC). The effects of volume fraction and particle size of spheroidal cementite on the interphase stress state are estimated. The experimental results are in good agreement with the theoretical relationships reported in the previous studies.
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  Effect of Chromium on CCT Diagrams of Novel AirCooled Bainite Steels Analyzed by Neural Network

  YOU Wei;XU Weihong;LIU Yaxiu;BAI Bingzhe;FANG Hongsheng

  中国钢铁期刊网. 2007, 14(4): 39-0.

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  The quantitative effects of chromium content on continuous cooling transformation (CCT) diagrams of novel aircooled bainite steels were analyzed using artificial neural network models. The results showed that the chromium may retard the high and mediumtemperature martensite transformation.
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  Dry Sliding Oxidative Wear in Plain Carbon Dual Phase Steel

  V Abouei;H Saghafian;Sh Kheirandish

  中国钢铁期刊网. 2007, 14(4): 43-0.

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  To investigate the tribological potential of the dual phase (DP) steel as a wear resistant material, the wear and the friction characteristics of this steel, which consists of hard martensite islands embedded in a ductile ferrite matrix, have been investigated and compared with those observed in plain carbon hardened (H) steel that has the same carbon content of 02%. Dry sliding wear tests have been carried out using a pinondisk wear testing machine at different normal loads of 213 N, 285 N, 357 N, and 426 N and at a constant sliding velocity of 120 m/s. The analysis of surface and wear debris of samples showed that the wear mechanism was mainly mild oxidative. The friction and the wear rate of the H steel and the DP steel have been explained with respect to the microstructure and the wear mechanism.
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  Numerical Simulation of Austenite Recrystallization in CSP Hot Rolled CMn Steel Strip

  TANG Guangbo;LIU Zhengdong;DONG Han;GAN Yong;KANG Yonglin;LI Liejun;MAO Xinping

  中国钢铁期刊网. 2007, 14(4): 49-0.

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  An integrated mathematical model is developed to predict the microstructure evolution of CMn steel during multipass hot rolling on the CSP production line, and the thermal evolution, the temperature distribution, the deformation, and the austenite recrystallization are simulated. The characteristics of austenite recrystallization of hot rolled CMn steel in the CSP process are also discussed. The simulation of the microstructure evolution of CMn steel ZJ510L during CSP multipass hot rolling indicates that dynamic recrystallization and metadynamic recrystallization may easily occur in the first few passes, where nonuniform recrystallization and inhomogeneous grain size microstructure may readily occur; during the last few passes, static recrystallization may occur dominantly, and the microstructure will become more homogeneous and partial recrystallization may occur at relatively low temperature.
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  Effect of Plastic Deformation on Magnetic Properties of Fe40%Ni2%Mn Austenitic Alloy

  Selva Büyükakka?瘙
  塂;H Aktas;S Akturk

  中国钢铁期刊网. 2007, 14(4): 56-0.

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  The effects of plastic deformation on the magnetic properties of austenite structure in an Fe40%Ni2%Mn alloy is investigated by using Mssbauer spectroscopy and Differential Scanning Calorimetry (DSC) techniques The morphology of the alloy has been obtained by using Scanning Electron Microscopy (SEM). The magnetic behaviour of austenite state is ferromagnetic. After plastic deformation, a mixed magnetic structure including both paramagnetic and ferromagnetic states has been obtained at the room temperature. The volume fraction changes, the effective hyperfine fields of the ferromagnetic austenite phase and isomery shift values have also been determined by Mssbauer spectroscopy. The Curie point (TC) and the Neel temperature (TN) have been investigated by means of DSC system for nondeformed and deformed FeNiMn alloy. The plastic deformation of the alloy reduces the TN and enhances the paramagnetic character of austenitic FeNiMn alloy.
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  Effect of Additive Cu10Sn Alloy on Sintering Behavior of Elemental Powders in Composition of 465 Stainless Steel

  Farid Akhtar;

  中国钢铁期刊网. 2007, 14(4): 61-0.

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  The addition of Cu10Sn alloy for developing the high strength 465 maraging stainless steel from elemental powders was studied. The sintering parameters investigated include the sintering temperature, the sintering time, and the mass percent of Cu10Sn. For vacuum sintering, effective sintering occurs at temperature between 1 250 ℃ and 1 300 ℃. The maximum sintered density was achieved at 1 300 ℃ for 60 min with 3% (in mass percent) Cu10Sn alloy. More than 3% (in mass percent) Cu10Sn content and temperature above 1 300 ℃ caused slumping of the samples. A maximum density of 74 g/cm3 was achieved with 3% (in mass percent) Cu10Sn content at a sintering temperature of 1 300 ℃ for 60 min. A maximum ultimate tensile strength (UTS) of 517 MPa was achieved with 3% (in mass percent) Cu10Sn content. With content higher than 2% (in mass percent) Cu10Sn, a maximum increase in the density was observed. The fracture morphologies of the sintered samples are also reported.
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  Influence of Bath Composition on Magnetic Properties of Electrodeposited CoPtW Thin Films

  GE Hongliang;WEI Guoying;WU Qiong;ZHOU Qiaoying;WANG Xinyan

  中国钢铁期刊网. 2007, 14(4): 65-0.

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  Effect of bath composition ([Co2+]/[PtⅣ] and [WO2-4], [cit-]) and pH on the magnetic properties of electrodeposited CoPtW thin films has been investigated. Electrodeposited CoPtW thin films exhibited strong perpendicular magnetic anisotropy when the ratio of [Co2+] to [PtⅣ] was 10; cathode current efficiency and perpendicular magnetic anisotropy showed little variations when [WO2-4] was lower than 01 mol/L, but perpendicular magnetic anisotropy had strengthened when [WO2-4] was over 01 mol/L, which could be explained by the fact that the hydrogen evolution could produce pores as magnetic domain pinnings; citrate as complexing reagent can promote the polarization of [Co2+] and [PtⅣ]. As a result, the equilibrium electrode potentials of cobalt and platinum moved to negative direction, which led to the codeposition of Co, Pt, and W. It was also found out that the asdeposited CoPtW hard magnetic thin films were very homogeneous, smooth, and had the maximum coercivity for the bath pH 85 and the concentration of citrate 026 mol/L.
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  Nanocrystalline and Nanocomposite Magnetic Materials and Their Applications

  Robert D Shull

  中国钢铁期刊网. 2007, 14(4): 69-0.

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  Nanocrystalline materials can possess bulk properties quite different from those commonly associated with conventional largegrained materials. Nanocomposites, a subset of nanocrystalline materials, in addition have been found to possess magnetic properties which are similar to, but different from, the properties of the individual constituents. New magnetic phenomena, unusual property combinations, and both enhanced and diminished magnetic property values are just some of the changes observed in magnetic nanocomposites from conventional magnetic materials. Here, a description will be presented of some of the exciting new properties discovered in nanomaterials and the magnetic applications envisioned for them.
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  Heredity of Aluminum Melt Caused by Electric Pulse Modification (Ⅰ)

  WANG Jianzhong;QI Jingang;DU Huiling;ZHANG Zhenbin;

  中国钢铁期刊网. 2007, 14(4): 75-0.

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  The heredity of aluminum melt under the action of pulse electric field was investigated by means of the remelt experiment. A new hereditary criterion under this condition was proposed; in the meantime, the differential transferability of genetic carrier in activated melt among filial generations was validated with the aid of DSC.