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    15 May 2004, Volume 25 Issue 5 Previous Issue    Next Issue

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    OriginalPaper
    Prediction modelling and software developed for microstructure and properties of hot-roll strip steel
    Zhang, Liang-Zhe (1); Wu, Di (1); Zhao, Xian-Ming (1)
    2004, 25 (5):  409-411.  DOI: -
    Abstract ( 242 )   HTML   PDF (111KB) ( 675 )  
    Based on the physical-metallurgical theory, the recrystallization, precipitation and phase transformation were modelled in the hot-rolling process of HSLA steel strip. As a result, the parameters of both microstructure and properties can be calculated quantitatively, with a software developed to predict them in accordance to actual technological process. The results showed a good agreement with those measured experimentally. The software can greatly save time and cost, and it is easy to use and maintain. So the software has good prospects in application.
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    Process control system for plate mill in Shougang
    Jiao, Zhi-Jie (1); He, Chun-Yu (1); Chen, Bo (2); Wang, Guo-Dong (1)
    2004, 25 (5):  412-415.  DOI: -
    Abstract ( 304 )   HTML   PDF (208KB) ( 869 )  
    A two-level process control system was developed independently and applied to the 3500 mm plate mill in Shougang in Beijing. Covering such functional modules for data communication, management, process tracking and model computation, they are used correspondingly for data communication among the process control system and other system; database reading/writing, model parameter querying for computation and actual process parameter recording for each and every workpiece, position/data tracking for workpieces to actuate other functional models at different points so as to control/schedule all workpieces automatically, and model computing for pass schedule and cooling system control. With those modules working collaboratively, a model-adaptive and fully automatic rolling control is available, which has been used in site successfully.
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    Relationship between different phase equilibria of Al-Zn-Cu alloys in low-copper part at room temperature
    Chen, Hui (1); Xin, Xin (1); Dong, Dan-Yang (1); Hao, Shi-Ming (1)
    2004, 25 (5):  416-419.  DOI: -
    Abstract ( 240 )   HTML   PDF (183KB) ( 504 )  
    The phase composition and relevant constituents of 14 different alloys designed for Al-Zn-Cu system were analyzed by means of microscopy, XRD and EPMA, which were all fully homogenized and evenly cooled step to step to 20°C. Among them the T' phase (A4Cu3Zn) was found in 11 alloys, then the composition of T' phases in 4 alloys were determined with the relationship between new phase equilibria. The results prove in another way that the T' phase may exist stably at room temperature, i.e., 20°C. In addition to the conclusion, it also indicates that the relationship between the phase equilibria low-copper part on the isothermal section diagrams at 20°C of Al-Zn-Cu alloys, which were shown in the collection of phase diagrams as published by ASM in 1997, is improper.
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    Experimental study on resistance of pipeline steel X65 to H2S corrosion
    Wang, Ya-Nan (1); Wang, Chun-Huai (1); Tang, Ji-Quan (2); Liu, Chun-Ming (1)
    2004, 25 (5):  420-423.  DOI: -
    Abstract ( 424 )   HTML   PDF (241KB) ( 815 )  
    The resistance of pipeline steels to H2S corrosion was investigated experimentally with different microstructures involved. The results showed that the pipeline steel X65 supplied by Jiuquan Steel Works has a excellent resistance to H2S corrosion when its microstructure is mainly of acicular ferrites. Few inner cracks were observed on the sections of specimens that were subjected to H2S corrosion experiments besides some hydrogen bubbles of which the hydrogen arising from corrosion was absorbed at the inclusions in the steel. It implies that when hydrogen atoms are released from the corroded surface of steel, they diffuse quickly into the steel through H2S catalysis and agglomerate at the boundaries between inclusions and matrix to form molecular hydrogen. With the process going on, a high pressure is generated finally to form hydrogen bubbles.
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    Centrifugally compounded interface between high carbide high chromium steel and chromium-bearing grey cast iron
    Zhou, Li (1); He, Jiang-Ai (1); Xin, Qi-Bin (1); Liu, Chang-Sheng (1)
    2004, 25 (5):  424-426.  DOI: -
    Abstract ( 283 )   HTML   PDF (188KB) ( 994 )  
    The chemical compositions of high carbide high chromium steel and chromium-bearing grey cast iron were optimized through orthogonally designed experiments which were carried out on a horizontal cantilevered centrifugal machine to compound the steel and cast iron by way of a centrifugal casting process. Under different experimental conditions, the successfully compounded interfaces were obtained and carefully compared with each other and analyzed by microscopy. The results indicate that a compact compound layer as the interface is found between the steel and cast iron. After water quenching at 1080°C for 1 hr then tempering at 500°C for 1 hr, although the carbides in the interface diffuse better, they do not affect the interface width. However the higher the casting temperature is, the wider the interface will be, if the casting temperature of the steel increases up to 1480°C from 1460°C, the interface width will increase by 100 μm.
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    Electrochemical study on hydrogen storage property of CNTs
    Guo, Lian-Quan (1); Ma, Chang-Xiang (1); Zhang, Yu-Jie (2); Wang, Shuai (2)
    2004, 25 (5):  427-430.  DOI: -
    Abstract ( 472 )   HTML   PDF (198KB) ( 1372 )  
    An electrochemical process was conducted to store hydrogen in CNTs (carbon nanotubes), where the CNTs were used as the cathode of Ni-MH cells. In this experiment, the CNTs and Ni-nanopowder were taken as sample cathode with KOH solution as electrolyte. With 50 charge-discharge cycles tested for the Ni-MH cells to measure their charge/discharge capacity and power, the hydrogen storage property of CNTs was determined on an Arbin BF-2043 series battery testing system to control the testing procedure. The experimental results showed that when the charging current into a gram of CNTs was 120 mA, the discharge capacity would be 126.386 mA·h·g with a stable discharging process available to provide a utilization rate up to 97%. It is evident that CNTs is indeed a kind of challenging material for hydrogen storage, and the experiment can provide an experimental reference for preparing hydrogen storage cells made from CNTs.
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    Metallurgical characteristic of carbon-proportioning pellets mixed with Zn-bearing electric arc furnace dust
    Liu, Bai-Chen (1); Dai, Shu-Hua (1); Shen, Feng-Man (1); Yu, Ai-Bing (2)
    2004, 25 (5):  431-434.  DOI: -
    Abstract ( 235 )   HTML   PDF (167KB) ( 537 )  
    The carbon-proportioning pellets are made from Zn-bearing EAF dust mixed with appropriate anthracite through roasting process. The influences of roasting temperature/time and proportioned quantity of coal on the metallurgical characteristics of the pellets were investigated at 1150-1300°C. The results show that the dezincification and metallization rate go up with the increase of roasting temperature/time and proportioned quantity of coal. As to the compressive strength, it also goes up with the increase of roasting temperature and time, but increases firstly then decreases with the increasing coal quantity. The best processing parameters are taking 15 min as roasting time at 1250°C with 13.04% taken as the value of the coal quantity in proportion to dust weight. Under such conditions, the dezincification rate, the metallization rate and the compressive strength of single pellet are 98.43%, 94.51 % and 800.6 N, respectively.
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    Experimental study on gas flow distribution laws in pelletizing shaft furnace
    Dong, Hui (1); Cai, Jiu-Ju (1); Wang, Guo-Sheng (1); Tian, Hong (1)
    2004, 25 (5):  435-438.  DOI: -
    Abstract ( 250 )   HTML   PDF (220KB) ( 1144 )  
    The palletizing shaft furnace(PSF) with internal channels and drying bed is a conventional pellet roasting equipment in China. According to the principle of similitude, a cold-state experimental setup was built to study the gas flow distribution in PSF. Based on the experimental data, representative flow-net diagrams are plotted to make sure of gas flow distribution in PSF and, further, to ascertain how the operating parameters affect the gas flow distribution in PSF. Some conclusions are therefore drawn as follows. The gas flow distribution will depend on the ratio of inflow, k, if the constructional parameters of PSF are constant, if the ratio of inflow k is critical, i.e., a critical operating condition. The roasting and cooling gases will entirely flow into the roasting zone and the internal vertical air channels (internal channels for short), respectively. When starting from such a critical operating condition to increase roasting gas flow or decrease cooling gas flow, the roasting gas starts flowing downwards so as to enter inside the inner channels, and the greater the ratio k is, the larger the downward flowrate will be. On the contrary, when starting from the same condition to decrease roasting gas flow or increase cooling gas flow, the cooling gas starts flowing upwards so as to enter into the roasting zone, and the smaller the ratio k is, the larger the upward flowrate will be. However, in the two cases as above-mentioned, there will be only one which is possible to take place at the same time, otherwise both are impossible.
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    Experimental study on improving quality of sintered ore by adding boric acid
    Zhou, Dong-Hui (1); Sun, Ting (1); Bai, Li-Qun (1)
    2004, 25 (5):  439-441.  DOI: -
    Abstract ( 239 )   HTML   PDF (936KB) ( 652 )  
    The iron-containing raw materials affect greatly the stability of blast furnace when they are pulverized at the upper part of the furnace, especially when the sintered ore is pulverized in the deoxidizing process at 400-600°C. To improve the quality of sintered ore and suppress the pulverization due to phase transition in temperature falling process, an experiment was conducted to use boric acid as additive into the mixture to be sintered. Then the experimental results were analyzed and discussed via drum test, granule size distribution and XRD. It was revealed that adding boric acid properly into the mixture could change the microstructure and strength of sintered ore, i.e., 0.6-1.2 kg boric acid per each 1 t of the mixture. As a result, the pulverization can be suppressed so as to improve the strength of sintered ore without any change needed in sintering procedure.
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    Preparation of Al-Si alloy by molten salt electrolysis
    Yu, Xu-Guang (1); Qiu, Zhu-Xian (1)
    2004, 25 (5):  442-444.  DOI: -
    Abstract ( 678 )   HTML   PDF (242KB) ( 1027 )  
    Al-Si alloys were produced by molten salt electrolysis using the molten cryolite-alumina system as electrolyte with SiO2 added in it. The morphology and chemical composition of such products were analyzed by SEM. The results indicated that the Si-content in alloys could be over 30% and therefore the products were hypereutectic Al-Si alloys. The morphological observation showed that the crystalline Si was typically of acicular structure. The hypereutectic Al-Si alloys can be used as Al-Si master alloy. Based on the experimental results, the mechanism of the process of preparing Al-Si master alloys was discussed. The reasons why the Al-Si master alloys form are considered as: 1) SiO2 is reduced by Al and 2) Si and Al are precipitated simultaneously on cathode. So keeping up the concentrations of A12O3 and SiO2 can make the electrolysis last all through. As a new approach to producing Al-Si master alloy, the preparation proposed is applicable to practical production.
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    Effects of grain graduation on vibratory packing efficiency in synthesizing NiFe2O4-spinel based inert anode
    Jiao, Wan-Li (1); Liu, Yi-Han (1); Yao, Guang-Chun (1); Zhang, Lei (1)
    2004, 25 (5):  445-448.  DOI: -
    Abstract ( 173 )   HTML   PDF (187KB) ( 598 )  
    The effects of the size distribution of coarse-fine binary particles and the volume fraction of fine particles on the vibratory packing efficiency and porosity of NiFe2O4-spinel powder were studied according to the Furnas model and linear packing density theory. It is found that the vibratory packing efficiency is higher whereas the porosity is lower when the size ratio (R) of coarse particles to fine particles increases. In addition, the vibratory packing efficiency reaches its peak value when the volume fraction of fine particles is 0.3-0.4. Comparing the experimental results of which the widest distributed group of granularity was chosen, i.e., the coarse particle size was 1.00-0.85 mm, to the values calculated by Furnas model, it was found that Furnas model suited the NiFe2O4-spinel powder system when the size ratio R was equal to or less than 5. But when the size ratio R was equal to or more than 7, the parameter C2 in Furnas model was preferably to be changed to 6.
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    Adaptive fuzzy control based on approximation errors for nonlinear systems
    Wei, Xin-Jiang (1); Jing, Yuan-Wei (1)
    2004, 25 (5):  449-452.  DOI: -
    Abstract ( 218 )   HTML   PDF (174KB) ( 415 )  
    A stable adaptive fuzzy control method is proposed for a class of uncertain single input/output nonlinear systems, of which the state variables are estimated by designing a fuzzy state observer instead of the assumption that these variables need a full observability. Such unknown nonlinearities are approximated by the fuzzy logic systems on the key assumption that the approximation errors satisfy certain bounding conditions. Then, Lyapunov synthesis is used to analyse the fuzzy system to obtain the adaptive laws of corresponding parameters. Such an overall control systems can guarantee not only that the tracking error converges in a small neighborhood of zero but also that all signals involved are uniformly bounded. Finally, a simulation example is given to testify the validity and efficiency of the proposed method.
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    State feedback robust H control for T-S fuzzy descriptor systems
    Zhu, Bao-Yan (1); Zhang, Qing-Ling (1); Da, Ke-Ning (2)
    2004, 25 (5):  453-456.  DOI: -
    Abstract ( 197 )   HTML   PDF (163KB) ( 768 )  
    The relations between the fuzzy descriptor subsystems and the overall systems are discussed on the regularity, impulse-free and stability. It is illustrated that the regularity, impulse-free and stability of the subsystems cannot guarantee those of the overall fuzzy descriptor systems composed of such subsystems. For this reason, it is possible and necessary to study the systems. A class of robust H control for T-S fuzzy descriptor systems with regularity and impulse-fee is thus discussed. The sufficient conditions are given, under which a state feedback controller can be designed to provide the stability of the closed-loop system and satisfy the H-performance. The sufficient conditions are expressed via LMI. The simplicity and effectiveness of the control method proposed is shown by an example.
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    Robust capability of disturbance rejection for nonlinear systems satisfying Lipschitz condition
    Wang, Zhan-Shan (1); Zhang, Hua-Guang (1); Wang, Zhi-Liang (1)
    2004, 25 (5):  457-459.  DOI: -
    Abstract ( 207 )   HTML   PDF (236KB) ( 712 )  
    The relation between Lipschitz constant and index of disturbance rejection has been studied quantitatively. By designing a full-order state observer with disturbance rejection for the nonlinear systems satisfying Lipschitz condition, a sufficient condition of the stability of the observer is given by using H technique. In case the energy of external disturbance is finite, an explicit expression between Lipschitz constant and index of H disturbance rejection is obtained by transforming the expression to Riccati inequality. A conclusion is thus drawn that generally the greater the Lipschitz constant is, the higher the index of disturbance rejection will be, and vice versa. In view of the index of disturbance rejection, the nonlinear system satisfying Lipschitz condition to a certain degree is therefore considered quantitatively as that it hasn't a robust but weak capability of disturbance rejection.
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    New approach to continuous temperature measurement of liquid steel in CC tundish
    Ci, Ying (1); Xie, Zhi (1); Zhang, Hua (1)
    2004, 25 (5):  460-462.  DOI: -
    Abstract ( 286 )   HTML   PDF (205KB) ( 1387 )  
    Based on the theory of blackbody cavity, a new approach to continuous measurement of liquid steel temperature is proposed. In view of that the on-line blackbody cavity cannot satisfy the physical model of Kirchhoff's ideal blackbody and is featured radiatively with non-airtight and non-isothermal, a model is developed to compute the effective and integral emissivites of on-line blackbody cavity and applied to measure the temperature of liquid steel in CC tundish continuously. The test results showed that the new approach had higher price performance and its error was less than 3°C with the service life of up to 20-40 hours. Comparing the method with others in cost, it is equivalent to or little less than quick-thermocouple and less than Pt/Rh thermocouple for continuous measurement. It is available to use as a substitute for the conventional methods for intermittent measurement.
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    Model and implementation of resource management in satellite information network
    Pan, Cheng-Sheng (1); Liu, Yong-Bing (1); Jiang, Yue-Qiu (2); Wang, Guang-Xing (1)
    2004, 25 (5):  463-466.  DOI: -
    Abstract ( 236 )   HTML   PDF (155KB) ( 480 )  
    Analyzing the techniques of resource management on grids, a model for resource management in satellite information network was set up and implemented, based on the architecture, of its network management system and characteristics. In the architecture, the resource management is based on the dynamic division of management domain to form the hierarchy composed of core resource manager and local resource scheduler, by which the static resources and dynamic resources are processed separately. All the resources are described in XML in the system which is implemented in C++. The system could be incorporated into the satellite information network management system as one of its main functions.
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    Reliably guaranteed cost control of descriptor systems
    Chen, Yue-Peng (1); Zhang, Qing-Ling (1); Zhai, Ding (1); Xu, Tian-Qun (2)
    2004, 25 (5):  471-474.  DOI: -
    Abstract ( 274 )   HTML   PDF (248KB) ( 846 )  
    The reliably guaranteed cost control of a class of uncertain descriptor systems is discussed. The definition of reliably guaranteed cost of descriptor systems is given first. Thus, the sufficient and necessary conditions are obtained in terms of linear matrix inequalities(LMI), under which the resultant closed-loop descriptor systems are not only of quadratic stabilization but also the upper bound of the cost function when the systems are working in order. Moreover, another sufficient condition is also derived in terms of LMI, under which, when part of actuators are faulty, the resultant closed-loop descriptor systems can remain the same. Then, a reliably guaranteed cost controller is designed, with a numerical example given to illustrate the design method.
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    Optimal control of dynamic economic systems with state constraint
    Yang, Fan (1); Zhang, Qing-Ling (1); Zhai, Ding (1)
    2004, 25 (5):  475-477.  DOI: -
    Abstract ( 243 )   HTML   PDF (225KB) ( 503 )  
    Combining the known input-output model with the methods based on control theory, an economic system is analyzed for the macro regulation and control of it. Based on the dynamic input-output theory, an optimal control model is developed for the definite linear economic systems with an inequality constraint on state integrals. According to the principle of maximum without constraint, the study on the optimal control of this model is changed into that of a simple perturbation model to which an optimal feedback control is derived. Therefore, on suitable assumptions, the existence and uniqueness of both optimal technology and economic control strategy are obtained and discussed. It is revealed that they enable the real output to be ideal with the energy consumption and cost minimized. Finally, the optimal feedback control is given.
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    Faults diagnosis based on Lyapunov exponent and phase trajectory for a generator sets
    Hou, Rong-Tao (1); Chu, Xiang-Zhi (2); Ren, Li-Yi (1); Wen, Bang-Chun (1)
    2004, 25 (5):  478-481.  DOI: -
    Abstract ( 257 )   HTML   PDF (924KB) ( 643 )  
    Based on chaos theory and the motional characteristics of non-linear dynamical systems, the fault diagnosis for a rotor of turbo-set generator was discussed. Three different running states of the generator rotor were studied in time series to determine the largest Lyapunov exponents from acquired time series, combining with the phase trajectory diagrams analyzed in the three states. The results showed that the largest Lyapunov exponents of time series obtained in the three different running states were different greatly from each other, with the types of the faults of the generator rotor thus revealed. The results were proved by the phase trajectories reconstructed with displacements and velocity shown by the time series data. It means that the largest Lyapunov exponent can be used as a quantified value to judge the motional characteristics of non-linear dynamical systems. So, a new and reliable method called Lyapunov exponent-phase trajectory is proposed to diagnose and predict the faults of a turbo-generator set or other complex mechanisms.
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    Torsional vibration characteristics of gear system with a cracked shaft
    Li, Yun-Gong (1); Liu, Jie (1); Zhu, Qi-Bing (1); Wen, Bang-Chun (1)
    2004, 25 (5):  482-485.  DOI: -
    Abstract ( 313 )   HTML   PDF (319KB) ( 724 )  
    Based on the analysis of main parameters of gear system, such as meshing stiffness, transmission error and pitch impulse, a dynamical model of gear system with a cracked shaft is developed. The torsional vibration characteristics of cracked shaft and non-cracked shaft in gear system are studied. Because there are lots of parameters in gear system, an assumption is made that the transmitting ratio is an independent variable, so as to discuss the relationship among the torsional vibration characteristics and transmitting ratio, rotating speed and the cracked depth. The results show that the secondary and quadruple harmonic occurring at operating frequency is the main characteristic of torsional vibration, and the transmitting ratio and rotating speed are the key factors which affect the power crack-inducing vibration and its distribution on the two shafts.
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    Effect of plasma-arc quenched stripe on surface wear-out
    Zhang, Jian (1); Zhao, Wen-Zhen (2); Ding, Jin-Yuan (1); Ma, Xian-Gui (1)
    2004, 25 (5):  486-488.  DOI: -
    Abstract ( 234 )   HTML   PDF (180KB) ( 549 )  
    By changing the angle included between plasma-arc quenched stripe and moving direction, the friction factor in reciprocating motion was investigated at/under different speeds/loadings. The results indicate that the plasma-arc quenching process can change partly the metallographic structure of a workpiece, increase its hardness and greatly improve its frictional nature and function. Furthermore, changing the angle included between plasma-arc quenched stripe and moving direction can change the friction factor of related surfaces. When the angle is in the range from 90° to 78°, the lubrication conditions are optimized, so that the friction factor is the smallest with the best antifriction performance. In addition, the friction factor of plasma-arc quenched stripe can be reduced with the increase of load when keeping the speed constant. A conclusion is thus drawn that how to design the direction of plasma-arc quenched stripe on frictional surface is important because it is available to prolong the service life of the parts/materials to be used and reduce energy consumption.
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    Simulation platform for reconfigurable assembly line based on digital manufacturing environment
    Huang, Xue-Mei (1); Wang, Yue-Chao (2); Tan, Da-Long (2); Zhao, Ming-Yang (2)
    2004, 25 (5):  489-492.  DOI: -
    Abstract ( 213 )   HTML   PDF (122KB) ( 1205 )  
    With an assembly line of automotive transmission taken as industrial background, and in order to improve the flexibility and reconfigurability of manufacturing system, the multi-agent manufacturing and holonic manufacturing methodologies are applied to revolutionize traditional assembly line. To evaluate the reconfigurable assembly line based on both agent and holon before applying the new methodologies to actual manufacture, a proposal is set out to construct a simulation platform based on digital production line environment. Based on the discuss on the functional features of the simulation platform to evaluate the reconfigurable assembly line, the infrastructure of the simulation platform is constructed to support 3D layout design, engineering analysis of intelligent assembly cell, performance analysis and information and functional integration of multiple manufacturing resources of assembly line. The key technologies to develop the simulation platform are studied, including the functional integration of system, geometric modeling in visualization implementation and performance analysis by integrating agent modeling with discrete event simulation of reconfigurable assembly line.
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    Design of SD-PDM system in CIMS environment
    Sheng, Zhong-Qi (1); Liu, Yong-Xian (1); Chen, Ji-Zhong (1)
    2004, 25 (5):  493-496.  DOI: -
    Abstract ( 236 )   HTML   PDF (151KB) ( 434 )  
    According to the surveying result of enterprise product and requirement and based on the integration environment of contemporary integration manufacturing system, the SD-PDM system is designed and developed for Shenyang Motor Joint-Stock Limited Company. The function requirement of the SD-PDM system is analyzed and mainly includes project management, task management, procedure management, product structure and configuration management. The opened system architecture is designed, which is composed of application layer, database layer, network layer and system layer, and the operation flowchart is given. At last some key technologies are introduced, including technology desktop choice, coding rule design and user right control. The SD-PDM system has run in the enterprise. It is proved that the SD-PDM has improved the management level and shortened the manufacturing and supplying time.
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    2004, 25 (5):  497-500.  DOI: -
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    2004, 25 (5):  505-507.  DOI: -
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    2004, 25 (5):  508-510.  DOI: -
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