2013年, 第20卷, 第8期　刊出日期：2013-08-15

  

• 全选
  |

工艺
• Select
  Theory-Intelligent Dynamic Matrix Model of Flatness Control for Cold Rolled Strips

  LIU Hong-min,,SHAN Xiu-ying,,JIA Chun-yu,

  中国钢铁期刊网. 2013, 20(8): 1-7.

  摘要 ( )   可视化   收藏

  In order to increase the precision of flatness control, considering the principle and the measured data of rolling process essence, the theory-intelligent dynamic matrix model of flatness control is established by using theory and intelligent methods synthetically. The network model for rapidly calculating the theory effective matrix is established by the BP network optimized by the particle swarm algorithm. The network model for rapidly calculating the measurement effective matrix is established by the RBF network optimized by the cluster algorithm. The flatness control model can track the practical situation of rolling process by on-line self-learning. The scheme for flatness control quantity calculation is established by combining the theory control matrix and the measurement control matrix. The simulation result indicates that the establishment of theory-intelligent dynamic matrix model of flatness control with stable control process and high precision supplies a new way and method for studying flatness on-line control model.
• Select
  Energy Consumption and Its Influencing Factors of Iron and Steel Enterprise

  DU Tao,SHI Tian,LIU Yong,YE Jian-bo

  中国钢铁期刊网. 2013, 20(8): 8-13.

  摘要 ( )   可视化   收藏

  Based on the theory of system energy-saving, a multilevel input-output computational model of the iron and steel enterprise was established. And one example was calculated using this model to analyze the product energy value, the process of energy consumption and energy consumption per ton of steel of an iron and steel enterprise. The influences of factory layout, steel ratio and production structure are calculated and analyzed. The calculation example indicates that reasonable factory layout is helpful to reduce its transportation energy consumption, decrease loss of heat, improve product rate and reduce environmental contamination; ore to steel ratio and iron to steel ratio decrease at the same degree; the influence of ore to steel ratio on energy intensity per ton is less than that of iron to steel ratio. The lord process product structure has a certain effect on comprehensive energy consumption per ton of steel.
• Select
  Approach of Synthesizing Model Predictive Control and Its Applications for Rotary Kiln Calcination Process

  ZHANG Li,GAO Xian-wen

  中国钢铁期刊网. 2013, 20(8): 14-19.

  摘要 ( )   可视化   收藏

  An actual control demand of rotary kiln is taken as background. By analyzing and improving approach of S-MPC (synthesizing model predictive control), an effective strategy which applies complex S-MPC in actual industrial process is designed. Firstly, after analyzing the main components technology and calcination reaction mechanism in detail, the calcining belt state-space model of rotary kiln is built using PO-Moesp (past-output multivariable output error state space model identification) method. Then, calcining belt temperature predictive control system is designed. The control system combines time-delay gain scheduled, output-tracking, recursive subspace adaptive and other methods, and forms the off-line/on-line predictive controller of rotary kiln. At last, MATLAB is applied for simulation, experiments run in constant value tracking and servo tracking situation. Simulation results show its effectiveness and feasibility.
• Select
  Process Optimization and Reaction Mechanism of Removing Copper From an Fe-Rich Pyrite Cinder Using Chlorination Roasting

  LIU Jian,WEN Shu-ming,CHEN Yu,LIU Dan,BAI Shao-jun,WU Dan-dan

  中国钢铁期刊网. 2013, 20(8): 20-26.

  摘要 ( )   可视化   收藏

  The aim is to remove copper from a pyrite cinder by optimizing the chlorination roasting process using response surface methodology (RSM) and the reaction mechanism of chlorination roasting based on thermodynamic calculation was discussed. A quadratic model was suggested by RSM to correlate the key parameters, namely, dosage of chlorinating agent, roasting temperature and roasting time to the copper volatilization ratio. The results indicate that the model is well consistent with the experimental data at a correlation coefficient (R2) of 095, and the dosage of chlorinating agent and roasting temperature both have significant effects on the copper volatilization ratio. However, a roasting temperature exceeding 1170 ℃ decreases the volatilization ratio. The optimum conditions for removing copper from the cinder were identified as chlorinating agent dosage at 5%, roasting temperature at 115510 ℃ and roasting time of 10 min; under such a condition, a copper volatilization ratio of 9516% was achieved from the cinder. Thermodynamic calculation shows that SiO2 in the pellet plays a key role in the chlorine release from calcium chloride, and the chlorine release reactions cannot occur without it.
• Select
  Effects of Microwave Heating on Pore Fractal Properties of Blast Furnace Sludge

  GAO Zhi-fang,LI Liao-sha,WU Zhao-jin,SHEN Xing-mei,Lv Hui-hong,SU Shi-huai

  中国钢铁期刊网. 2013, 20(8): 27-33.

  摘要 ( )   可视化   收藏

  Effects of microwave heating on the pore fractal properties of blast furnace sludge (BFS) and relative mechanism were studied. The results show that the morphology features of iron bearing sinter and coke particles, which are the main constituents of the BFS, were remarkably changed by microwave heating. The porosity, surface roughness and specific surface area of modified particle surface all increased obviously. Combining with fractal method called Sierpinski model, the fractal dimensions of sinter, coke and others increased from 235, 224 and 258 to 265, 244 and 261 respectively, after modification by microwave heating. The results predicted that the reaction mechanism of microwave heating for BFS is related to two aspects. Different mineral phases existed in BFS particles incline to dissociate each other due to their different microwave absorbability;some recombination or reconstruction of matters or structure leads to structure defects, which have great influences on the surface morphology characteristics and chemical properties. The research indicated that fractal dimension can be used as an effective factor for quantitative analysis of the pore changes in morphology of the sludge. Furthermore, it is helpful for separation and extraction of valuable constituent from BFS.
• Select
  Solid-Phase Decarburization of High-Carbon Ferromanganese Powders by Microwave Heating

  GUO Li-na,CHEN Jin,SHI Wen-li,ZHAO Jing,LIU Ke,LIU Jin-ying

  中国钢铁期刊网. 2013, 20(8): 34-40.

  摘要 ( )   可视化   收藏

  The solid-phase decarburization of high-carbon ferromanganese powders (HCFPs) was investigated using calcium carbonate as the decarburizer by microwave heating and conventional heating methods to explore the differences of microwave heating and conventional heating. Experimental results show that HCFPs containing calcium carbonate were heated up to 900, 1000, 1100, and 1200 ℃ and held for 60 min for decarburization by microwave heating at decarburization ratios of 7669%, 8290%, 8411%, and 8575%, respectively. These ratios are higher than the decarburization ratios used for conventional heating under the same experimental conditions. The microwave heating can significantly improve decarburization ratio. This indicates the microwave heating field features a non-thermal effect, which in turn, visibly enhances the carbon diffusion ability of HCFPs. It also improves the kinetic conditions of solid-phase decarburization.
• Select
  Optimization of Low Phosphorus Steel Production With Double Slag Process in BOF

  YANG Xiao,SUN Feng-mei,YANG Jin-li,LIU Fei,CHENG Kui-sheng,WANG Jian-hua

  中国钢铁期刊网. 2013, 20(8): 41-47.

  摘要 ( )   可视化   收藏

  To produce the steel with phosphorus less than 0007% (mass percent), the double slag process has been optimized in basic oxygen furnace (BOF). Dephosphorization and decarburization are performed in sequence in the same converter. Deslagging is conducted twice, each at the end of dephosphorization and decarburization, by tilting the BOF. Production was tested in a 180 t BOF. Mass percent of phosphorus in steel at BOF blow end has been made to as low as 00042% after optimizing operational parameters. Factors affecting dephosphorization performance were studied. Before intermediate deslagging, dephosphorization is determined by the mass transfer of phosphorus from metal/slag interface to bulk slag phase rather than equilibrium thermodynamic conditions. After intermediate deslagging, dephosphorization is determined by the equilibrium thermodynamic conditions such as slag composition and temperature.
材料
• Select
  Dynamic Deformation Behavior of Dual Phase Ferritic-Martensitic Steel at Strain Rates From 10-4 to 2000 s-1

  SONG Ren-bo,DAI Qi-feng

  中国钢铁期刊网. 2013, 20(8): 48-53.

  摘要 ( )   可视化   收藏

  The deformation behavior of the dual phase steel (DP1000 steel) was studied by the quasi-static tensile experiment and the dynamic tensile experiment. The experiments were carried out at strain rates ranging from 10-4 to 2000 s-1 at room temperature. Then the stress-strain curves of DP1000 steel in the strain rate range of 10-4-2000 s-1 were measured. By introducing the strain rate sensitivity factor m, Zerilli-Armstrong model was optimized. The constitutive equation parameters which formulate the mechanical behavior of DP1000 steel were fitted based on the Johnson-Cook (JC) constitutive model and the optimized Zerilli-Armstrong (ZA) constitutive model, respectively. By comparing indicators of “accuracy-of-fit”, R2 terms, for the two models, the optimized Zerilli-Armstrong constitutive model can reflect plastic deformation behavior both at the low and high strain rates more accurately. The reasons why the optimized Zerilli-Armstrong constitutive model is more advantageous than the Johnson-Cook model were discussed by using the yield strength and ultimate tensile strength (UTS) versus strain rates, and strain hardening rate versus effective plastic strain analytical methods.
• Select
  Mechanism of Black Strips Generated on Surface of CSP Hot-Rolled Silicon Steel

  LIU Xiao-jiang,CAO Guang-ming,NIE Da-ming,LIU Zhen-yu

  中国钢铁期刊网. 2013, 20(8): 54-59.

  摘要 ( )   可视化   收藏

  Because of the effect of silicon on the formation of oxide scale, black strip defect is common on the surface of compact strip production (CSP) hot-rolled silicon steel, which leads to difficulty in pickling process compared with plain carbon steels. Although high-temperature oxidation of Fe-Si alloy has been discussed a lot, few studies have explained the mechanism of black strip defect generated on the surface of hot-rolled silicon steel and proposed means to prevent it effectively. Thermogravimetric analyzer (TGA) is used to simulate oxidation of Fe-22Si alloy for 30 min under air condition, and temperature range is from 1000 to 1150 ℃. Effect of rolling deformation on scale morphology is also discussed. Electron probe microanalysis (EPMA) is used to analyze cross-sectional morphology and elemental distribution of the oxide scale. Schematic diagram of formation of black strip defect is obtained, which helps to provide theoretic basis for proposing of solutions for the problem. It is proposed that lowering furnace temperature and shortening time to stay at high temperature condition after rolling will be helpful to relieve the black strip problem.
• Select
  Effect of Controlled Cooling on Microstructure and Mechanical Properties of H-Beam

  GUO Fei,ZHAO Xian-ming,WANG Li-na,WU Di,WANG Guo-dong,NING Zhong-liang

  中国钢铁期刊网. 2013, 20(8): 60-65.

  摘要 ( )   可视化   收藏

  Based on ANSYS, an analytical model was established for H-beam during controlled cooling. The temperature fields during controlled cooling and air cooling were analyzed and the microstructure and mechanical properties for different parts of H-beam were discussed in detail. After the H-beam was controlled cooled for 45 s, its mean surface temperature decreased from 850 to 460 ℃, and the lowest and the highest temperatures were measured at edge of flange and at R corner, respectively. Whereas, for the H-beam air-cooled for 30 s, the mean temperature at R corner and web was 700 and 540 ℃, respectively. The microstructures for different parts of H-beam consisted of ferrite and pearlite, and the grain size at R corner was coarser than those at flange and web. The difference of yield and tensile strengths of web, flange and R corner was within 30 MPa, and the elongation was similar. The changes of microstructure were in good agreement with that of temperature field. In addition, the results show that the uniformity of microstructure and mechanical properties can be improved by increasing water flow rate at R corner.
• Select
  Effect of Crystallographic Texture on Anisotropy of Yield Strength in X100 Pipeline Steel

  ZONG Cui,ZHU Guo-hui,,MAO Wei-min

  中国钢铁期刊网. 2013, 20(8): 66-71.

  摘要 ( )   可视化   收藏

  The anisotropy of microstructures and mechanical properties in commercial American Petroleum Institute (API) X100 pipeline steel was systematically investigated by experimental measurements. The experimental results show that anisotropy of yield strength could be observed considerably, which should be attributed to the crystallographic textures due to deformation and transformation of texture components. This is because the effect of the inhomogeneity of microstructure in different directions on the mechanical properties could be reasonably neglected based on the experimental investigation of grain size distribution. The effect of crystallographic texture on the anisotropy of yield strength was interpreted theoretically based on the relationship between yield strength and average orientation factor.
• Select
  Impact Toughness of an NM400 Wear-Resistant Steel

  SONG Hong-yu,LI Can-ming,,LAN Liang-yun,ZHAO De-wen,WANG Guo-dong

  中国钢铁期刊网. 2013, 20(8): 72-77.

  摘要 ( )   可视化   收藏

  An NM400 wear-resistant steel was hot rolled and then the plates were heat-treated by direct quenching and tempering (DQT) and reheat quenching and tempering (RQT) techniques, respectively. The Charpy impact test was carried out with an instrumented Charpy impact tester. The microstructure and fracture surface were investigated by a combination of optical microscopy, transmission electron microscopy and scanning electron microscopy methods. It was found that the impact toughness of DQT specimen was much higher than that of RQT specimen. The microstructure of both DQT and RQT specimens was characterized by a mixture of tempered lath martensite and lower bainite. The lower bainite in DQT specimen extended into prior austenite grains and the content was higher than that in RQT specimen. The lower bainite in DQT specimen improved the impact toughness by increasing the proportion of large-angle boundaries and relieving the stress concentration at the crack tip. A number of fine and dispersed carbides in DQT specimen also contributed to the improvement of the impact toughness.
• Select
  Microstructure of Fe-Based Alloy Composite Coatings Reinforced by Ti(C03N07) Particles Through Laser Cladding Technology

  QI Yong-tian,CAO Zhao-xia,SHENG Li-ying,CAO Run-ping

  中国钢铁期刊网. 2013, 20(8): 78-82.

  摘要 ( )   可视化   收藏

  Fe-based alloy layer reinforced by Ti(C,N) particles was produced on the surface of cast steel. X-ray diffraction (XRD) was used for phase identification in the composite coating. The microstructure of laser cladding layer was analyzed by means of optical microscope (OM), electron probe microscope analyzer (EPMA), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that Ti(C03N07) particle is introduced by an in-situ metallurgical reaction of TiN particle and graphite powder in the process of laser cladding. The shape of lots of Ti(C03N07) particle is irregular. The sizes of Ti(C03N07) particles range from 01 to 60 μm, and they are dispersed evenly in the matrix, which is fine dendritic or cellular crystal. A new kind of phase named Ti(C03N07) particles are tightly bonded with α-Fe microstructure, and there is a clean and smooth phase interface between ceramic reinforcement phase and the matrix.
• Select
  Hot Ductility of DSS and Its Microstructure Observation During Hot Deformation

  SONG Zhi-gang,ZHENG Wen-jie,FENG Han,WU Zhong-zhong,GUO Hai-sheng,YU Fei

  中国钢铁期刊网. 2013, 20(8): 83-86.

  摘要 ( )   可视化   收藏

  By selecting several typical duplex stainless steels (DSS), ie, 00Cr22Ni5Mo3N, 00Cr21Ni2Mn5N and 00Cr25Ni7Mo4N, as research materials, hot ductility characteristic of DSS was studied by thermal simulation method and microstructure evolution during hot compression was observed through TEM. The results show that the optimum hot ductility temperature range of DSS is 1050-1200 ℃. 00Cr25Ni7Mo4N exhibits the worst hot ductility and 00Cr21Ni2Mn5N has similar hot ductility to 00Cr22Ni5Mo3N. During hot compression, the dynamic recovery of austenite occurs in DSS while the dynamic recovery and recrystallization of ferrite take place in 00Cr22Ni5Mo3N and 00Cr21Ni2Mn5N, but only the dynamic recovery of ferrite can be observed in 00Cr25Ni7Mo4N.
• Select
  Corrosion Behavior of Different Steel Substrates Coupled With Conductive Polymer Under Different Serving Conditions

  LIU Xiao-hei,XIA Zhi-dong,ZHOU Hu,YUAN Bo,LI Zhe,GUO Fu

  中国钢铁期刊网. 2013, 20(8): 87-92.

  摘要 ( )   可视化   收藏

  The corrosion behaviors of stainless steel and nickel-plated carbon steel coupled with conductive polymer were investigated in both hot humid environment and simulated marine environment. The corrosion currents of different steel substrates and conductive polymer in simulated marine environment at room temperature were measured. The corrosion surfaces of different steel couples were observed under a scanning electron microscope (SEM) and chemical compositions were examined by energy dispersive spectrum (EDS) analysis. The corrosion mechanism was discussed. The results showed that the stability of both stainless steel and nickel-plated carbon steel in hot humid environment was excellent and no corrosion happened in the blank test for 360 h while slight corrosion existed in the contact area of coupled steel substrates. In simulated marine environment, the corrosion current of the stainless steel was lower than 100 μA and some directional rod-like particles formed on the surface of the stainless steel, which are mainly caused by oxidative corrosion among different phases. The corrosion current of the nickel-plated carbon steel couples was much greater than that of stainless steel couples and nickel plate cracking resulted in the corrosion of the internal iron because the coated nickel layer was not dense enough.