Sample records for roll mill grinding

  1. Rheology of coal-water slurries prepared by the HP roll mill grinding of coal. Quarterly technical progress report number 11, March 1--May 31, 1995

    Fuerstenau, D.W.


    The objective of this research is the development of improved technology for the preparation of coal-water slurries that have potential for replacing fuel oil in direct combustion. Detailed investigations of the effect of solids content and chemical additives on the rheology of coal-water slurries, prepared with fines produced by the ball milling of Pittsburgh No. 8 coal, were conducted during the first phase of the research program. These experiments were to provide a baseline against which the rheological behavior of slurries prepared with fines produced by high-pressure roll milling or hybrid high-pressure, roll mill/ball mill grinding could be compared. The viscosity of slurries with high solids content is strongly influenced by the packing density of the feed material. The packing density can be significantly altered by mixing distributions of different median sizes, and to an extent by modifying the grinding environment. The research during this quarter was, therefore, directed towards: (1) establishing the relationship between the packing characteristic of fines and the viscosity of slurries prepared with the fines; (2) investigation of the effect of mixing distribution on the rheology; and (3) study of the effect of grinding environment in the ball mill on the rheology of coal-water slurries.

  2. Optimization of Preventive Grinding of Backup Roll against Contact Fatigue Cracking

    DOU Peng; LI You-guo; LIANG Kai-ming; BAI Bing-zhe


    In order to optimize the current grinding procedure of the backup roll of 2050 continuously variable crown (CVC) mills, the behavior of rolling contact fatigue (RCF) cracking was investigated. Two RCF short cracks, including vertical short crack and ratcheting short crack initiated from ratcheting, were observed. The behavior of both RCF cracks was analyzed in detail. Then a modified grinding procedure was proposed according to the behavior of RCF cracks and the preventive grinding strategy.

  3. Shear Roll Mill Reactivation


    accommodate a trial run of inert single base pellet feed for use in a twin screw extruder. 15. SUBJECT TERMS INIT248, Advanced Propellant Technology...Bldg. 4909-5 – Shear Roll Mill Pilot Plant at the Radford Army Ammunition Plant (RFAAP) in order to produce pellet feed for a twin screw extruder used...propellant to simulate feed for a twin screw extruder. Preventive maintenance procedures were in progress in final preparation for running with

  4. Continuous grinding mill simulation using Austin's model

    André Carlos Silva


    Full Text Available Comminution is a frequently-required step in mineral processing and is responsible for almost 90% of all energy consumption in a mineral processing plant. Tumbling mill design has been studied since the middle of the XIX century. There are many comminution models in the literature, with preponderance, however, of Austin’s model (2002 for mineral impact breakage. In this paper, Austin’s model was applied to tubular tumbling mills. Once Austin's model was proposed for batch processing of narrowly-distributed fraction sizes, an artifice has allowed it to be used in continuous grinding mill processes with widely-distributed fraction sizes. Interesting results were obtained with errors less than 0.005 for mills with sharp residence time distributions.

  5. Research on product size and grinding dynamics of vibration mills

    YIN Zhong-jun; HAN Tian; CHEN Bing; ZHANG Wen-zhong


    In order to improve vibration mills grinding effect and increase productive efficiency, prime factors of vibration mills were gained much attention. The purpose of this study is to reveal product size distribution and grinding dynamics of vibration mills by orthogonal experi-ments. The metallurgical refractory materials were used as research object. In order to explore the relationships between grinding effect and primary factors, lots of milling experiments were carried out. Based on the results, the conclusions can be summarized: as time runs, the size distri-bution shows exponential trend, and range becomes more and more narrow. Also the quantitative analysis result between grinding effect and primary factors was obtained by non-linear regres-sion: high frequency, high amplitude and low fill ratio can increase grinding speed.



    It is studied how the aluminum foil chatter mark is produced and controlledThe stableness of hydraulic AGC system,fluid vibration of capsule system,and electromechanical coupling of AC/AC VVVF system and dec oupling are also studiedIt is shown that rolling mill design should go to syst em dynamic design from traditional designThe framed drawing of system dynamic design program is presented


    José Claudino de Lira Júnior


    Full Text Available In hot rolling processes occur changes in the profile of the rolling mill rolls (expansion and contraction and constant wear due to mechanical stress and continuous thermal cycles of heating/cooling caused by contact rolled material- working roll and the cooling system by water jets in their surface, decreasing their lifetime. This paper presents a computational model to simulate the thermal performance of rolling mill rolls. The model was developed using the finite volume method for a transient two-dimensional system and allows calculating the temperature distribution of the rolling mill rolls under various conditions of service. Here it is investigated the influence of flow rate and temperature of the cooling water on the temperature distribution. The results show that the water temperature has greater influence than the water flow to control the surface temperature of the cylinders.

  8. Improvement on strip flatness of cold temper mills by modifying roll contour shape

    Xiaoyan Li; Jie Zhang; Xianlin Chen; Jianguo Cao; Haixia Li


    A study on roll gap profile (strip profile) control was accomplished in a 1700 mm single-stand temper mill. Some critical problems such as the deviation of work roll contour caused by grinding and wear, the effectiveness of work roll bending were discussed. Using a finite element model, the effects of roll contours (ground and wear) on strip profile were investigated. The roll bending effect on strip thickness was also analyzed. It is pointed out that there are some special features of flatness control in the temper mill: during temper rolling, roll deformation is slight due to small rolling load, and the loaded roll gap profile mainly depends on work roll contour, while the backup roll has a little effect on gap crown; the effect of bending force on gauge can not be ignored due to the coupling between flatness control and gauge control. A new roll contour arrangement adaptable to the mill was presented and has been put into practical production. The application of the new set of rolls showed some good results: larger crown control range of work roll bender, higher rolling stability, better strip profile and flatness quality.

  9. Grinding process within vertical roller mills: experiment and simulation

    WANG Jian-huai; CHEN Qing-ru; KUANG Ya-li; LYNCH A J; ZHUO Jin-wu


    Based on screening analysis, laser size analysis, grindability and rigidity tests of samples collected on line from a cement and a power plant, a simulation of the grinding process in vertical roller mills was carried out. The simulation calculation used a breakage function, B. The results indicate that the breakage function, B, and the selection function, S, in the form of a matrix, can be used to express the probability of the material breaking during the grinding process. This allows the size distribution of the product to be numerically estimated. The simulation results also show that the simulated size distribution curves fit the actual ex-perimental product curves quite well. The model provides a good starting point for simulation of the grinding process. Further re-search is needed to determine the proper breakage function and the matrix value of the selection function.

  10. Research on work roll thermal crown in cold rolling mill

    Song, Lei; Shen, Mingang; Chen, Xuebo; Wang, Junsheng


    The factors which have influence on the work roll thermal crown in cold strip rolling are discussed. The heat transferring in three directions (radial axis and circumference) were considered for calculating the work roll thermal deformation. Therefore, it is a three dimensions unstable system for the work roll temperature calculation. The plastic deformation work and friction heat are calculated by the divided element and digital integration method. The simplified calculation model is built for the heat transferring along work roll. There are four zones for work roll heat transferring: roll gap zone air cooling zone emulsion zone rolls contact zone. The heat transferring between the zones is decided by the temperature difference. The inter temperature field and thermal deformation of work roll can be calculated by two-dimension finite difference method. The work roll temperature and thermal crown of actual application cold rolling mill are analyzed by the model. By the comparison between calculated values and measured values, the work roll thermal calculation model can meet the accuracy requirement of on-line control.


    Arísio de Abreu Barbosa


    Full Text Available This paper outlines the main actions taken to reinforce the decision to use HSS work rolls on the Aperam Steckel Mill. These are: work roll cooling improvements, systematically analyzing Eddy Current and Ultrasonic non destructive tests, mechanical adjustment of work roll crown and critically examining the rolling process. These actions applied together have contributed to the success of HSS rolls state of the art application, and provide the Steckel Mill with a much improved performance. Significant results have been achieved, such as: increasing of work roll change intervals, increasing of the available production time, a yield gain, a product quality improvement, less working hours needed for the roll grinding operation, etc

  12. Roll Gap Crown Adjustment Characteristics of 1700 mm Cold Rolling Mills

    GUO Jian-bin


    The 4-hi cold mill is one of the key wide strip tandem cold rolling mills and has many advantages and characteristics. The mill type is the most important, fundamental and long-term effective factor for the strip shape control. Many advanced mill types such as CVC-4, HCW and PC-4, etc are created based on the conventional four-roll mill. The factors of mill type which affect the deformation of roll system, such as strip width, rolling force, bending force, work roll diameter, backup diameter and so on, are studied how to affect roll gap crown. It provides a good foundation for improving the shape performance of mill.

  13. Investigation for parametric vibration of rolling mill

    唐华平; 丁睿; 吴运新; 钟掘


    The vibration unsteady condition of rolling mill caused by flexural vibration of strip has been investigated. The parametric flexural vibration equation of rolled strip has been established. The parametric flexural vibration stability of rolled strip has been studied and the regions of stability and unstability have been determined based on Floquet theory and perturbation method. The flexural-vibration of strip is unstable when the frequency of variable tension is two times as the natural frequency of flexural-vibration strip. The characteristic of current in a temp driving motor's main loop has been studied and tested, it has been proved that there are 6 harmonic component and 12 harmonic component in main loop of driving motor electricity. The vertical vibration of working roller has been tested, the test result approves that the running unsteady is caused by parametric vibration. It attaches importance to the parametric vibration of rolling mill.


    K. V. Podmasteryev


    Full Text Available Base a possibility of monitoring processes of grinding the rolling bearings with use electroresistance method of check. Is write of essence this method, are analyses his peculiarities, which are provide objective information on the condition a object by his grinding. Are consider the results of experimental researches the effective different diagnostically parameters, which are confirm a possibility of realization objective check of grinding the rolling bearings with use electro-resistance method.

  15. Mechanical Property of Low Chromium Semi-Steel Grinding Ball Prepared by Cross Rolling

    CHANG Li-min; MENG De-liang; NIE Pu-lin; LIU Jian-hua


    The preparing method, rolling technology and mechanical properties of low chromium semi-steel grinding ball by cross rolling were studied. The results show that when the low chromium semi-steel bar is forged from 55 mm to 50 mm, cross-rolled into grinding ball at 1 000-1 050 ℃, air cooled and tempered at 550 ℃ for 2 h, the best mechanical properties, especially the abrasive resistance under the action of hard abrasive, can be obtained.

  16. Analysis of Roll Gap Pressure in Sendzimir Mill by FEM

    YU Hai-liang; LIU Xiang-hua; WANG Chao; Park Hae-doo


    The acting force on the roll system of Sendzimir mill was analyzed using 3D FEM. The roll gap pressure distribution and the acting force between rolls S and O, rolls O and I, rolls O and J, rolls I and A, rolls I and B, as well as rolls J and B were analyzed. The results showed that the roll gap pressure mainly affected the roll surface layer, 50 mm for backup roll; the roll gap pressure distribution is of double peaks among the work roll, the 1st intermediate roll (IMR), and the 2nd IMR; the maximum value of the roll gap pressure between the backup roll and the second IMR appears on the edge of the barrel of rolls; the component force presents the in-para-curve distribution. These are important for reducing the wear of rolls and the break of the backup roll and guiding for production.

  17. Research on Frequency Response Characteristics of Rolling Mill

    CaiZhengguo; ZhangKenan


    The measurement method of frequency response characteristics for rolling mill is established by imposing different signal excitation on PID input of rolling mill under the different rolling conditions. The analysis results declare that sweep sine signal was relative efficient to evaluation for the frequency response character of hydraulic system. The practical application shows that the corresponding relationship between the parameters and the frequency response range of the rolling mill is helpful for parameters verification of process control and condition monitoring of hydraulic system.

  18. Automatic Flatness Control of Cold Rolling Mill

    Anbe, Yoshiharu; Sekiguchi, Kunio

    One of the subjects of cold rolling is a flatness of the rolled strip. Conventionally, measured strip flatness was approximated by polynomial (2th, 4th, 6th) equation across the entire strip width. This made it difficult to deal with desired loose edge or any desired flatness across the entire strip width. Also conventional flatness control was done for the entire strip width, so if there is a different flatness error among drive side and work side, conventional flatness control can not control properly. We propose independent strip flatness control among drive side and work side, and also automatic flatness control (AFC) system with arbitrary desired strip flatness. Also some applied results to cold mill are shown.

  19. Strip shape control capability of hot wide strip rolling mills

    Renzhong Wang; Quan Yang; Anrui He; Jian Shao; Haitao Bian


    The elasticity deformation of rolls was analyzed by means of two-dimensional f'mite element method (FEM) with vari-able thickness. Three typical mills were used as objects for analysis. A thorough study was done on the control capabilities of these mills on the strip shape. Then the strip shape control capabilities of the three mills was compared synthetically.

  20. Properties of Cross-Rolled Low Alloy White Cast Iron Grinding Ball

    CHANG Li-min; LIU Lin; LIU Jian-hua


    The low-energy, multi-impact fracture resistance and the abrasiveness of the cross-rolled low alloy white cast iron grinding balls were studied after heat treatments at residual rolling temperature. Moreover, the means by which they are damaged and characters of the wear surface were analyzed. The results show that high resistance to impact fracture and high abrasiveness can be achieved after appropriate heat treatment at residual rolling temperature. This kind of heat treatment technology has several advantages under low impact and hard abrasive. These results are very useful for determining the optimized heat treatment technology at residual rolling temperatures.

  1. Investigation of the milling capabilities of the F10 Fine Grind mill using Box-Behnken designs.

    Tan, Bernice Mei Jin; Tay, Justin Yong Soon; Wong, Poh Mun; Chan, Lai Wah; Heng, Paul Wan Sia


    Size reduction or milling of the active is often the first processing step in the design of a dosage form. The ability of a mill to convert coarse crystals into the target size and size distribution efficiently is highly desirable as the quality of the final pharmaceutical product after processing is often still dependent on the dimensional attributes of its component constituents. The F10 Fine Grind mill is a mechanical impact mill designed to produce unimodal mid-size particles by utilizing a single-pass two-stage size reduction process for fine grinding of raw materials needed in secondary processing. Box-Behnken designs were used to investigate the effects of various mill variables (impeller, blower and feeder speeds and screen aperture size) on the milling of coarse crystals. Response variables included the particle size parameters (D10, D50 and D90), span and milling rate. Milled particles in the size range of 5-200 μm, with D50 ranging from 15 to 60 μm, were produced. The impeller and feeder speeds were the most critical factors influencing the particle size and milling rate, respectively. Size distributions of milled particles were better described by their goodness-of-fit to a log-normal distribution (i.e. unimodality) rather than span. Milled particles with symmetrical unimodal distributions were obtained when the screen aperture size was close to the median diameter of coarse particles employed. The capacity for high throughput milling of particles to a mid-size range, which is intermediate between conventional mechanical impact mills and air jet mills, was demonstrated in the F10 mill. Prediction models from the Box-Behnken designs will aid in providing a better guide to the milling process and milled product characteristics.

  2. Structural causes of defects in a cast iron mill roll

    J. Krawczyk


    Full Text Available This paper describes an analysis of a defective microstructure of a mill roll. For this purpose, a piece of a broken roll was collected. That roll was made of mottled cast iron. Its microstructure consisted of modular graphite, transformed ledeburite and a matrix composed of bainite and martensite. Metallographic investigations were performed nearby the fracture in the roll. Observations were conducted on polished sections, first not etched, and then etched, which allowed us to trace carefully the propagation of the fracture. There was found a strict correlation between the microstructure of the roll and the progress occurring in the crack. It was ascertained that the basic reason for the damage to the roll was banded precipitations of ledeburitic cementite. In addition, cementite formed a continuous network. Another microstructure defects of that roll are also precipitations of secondary carbides on the boundaries of former grain of austenite as well as the occurrence of upper bainite in its matrix. The results obtained hereunder allow broadening the data base relative to the genesis of damages to mill rolls, which in future will permit one to design a proper microstructure of cast iron mill rolls. Proper microstructure of cast iron mill roll should be shaped at the stage of designing the chemical composition, conditions of crystallization or heat treatment if any.

  3. Role of classification in grinding using the electromagnetic mill. A case study

    Wolosiewicz-Glab Marta


    Full Text Available In the process of classification, one of the methods used to evaluate the effectiveness classifiers is to plot a separation curve, which determines the size of seprated particles and characterizes the process accuracy. The article presents an assessment of the impact of parameters on grinding and classification using an electromagnetic mill. The results allow a detailed assessment of the effectiveness and efficiency of the device and facilitate the optimization of the grinding process by establishing an appropriate control algorithms.

  4. Improvement of rolling 6 mm thin plates in plate rolling mill PT. Krakatau Posco

    Pujiyanto, Hamdani


    A 6-mm thin plate is difficult to produce especially if the product requires wide size and high strength. Flatness is the main quality issue in rolling 6-mm plate using a 4-high reversing mill which use ±1100-mm work roll. Thus some methods are applied to overcome such issue in order to comply to customer quality requirement. Pre-rolling, rolling, and post-rolling conditions have to be considered comprehensively. Roll unit management will be the key factor before rolling condition. The roll unit itself has a significant impact on work roll crown wearness in relation with work roll intial crown and thermal crown. Work roll crown along with the modification of hydraulic gap control (HGC) could directly alter the flatness of the plate.

  5. Modeling for driving systems of four-high rolling mill

    贺建军; 喻寿益; 钟掘


    A modeling method for driving systems of four-high rolling mill was put forward in order to analyze the origin of rolling mill's chatter that brings about light and shade streaks on the surface of steel strip from aspect of electromechanical coupling. The process and steps of modeling method was introduced by means of an example. The correctness of the model and the feasibility of the modeling method were verified in simulation experiment.


    Kuznetsova M.M.


    Full Text Available The article presents results of theoretical and experimental research of grinding process of bulk materials in a ball mill. The new method of determination of energy efficiently mode of operation of ball mills in a process of a cement clinker grinding is proposed and experimentally tested.

  7. Investigation for Electromechanical Coupling Unstability of Rolling Mill


    The unsteady condition of rolling Mill vibration that was caused by flexural vibration of strip was investigated. The parametric flexural vibration equation of rolled strip was established. The parametric flexural vibration stability of rolled strip was studied and region of stability and unstability was determined based on Floquet theory and perturbation method. The flexural-vibration of strip was unstable if the frequency of variable tension was twice as the natural frequency of flexural-vibration strip. ...

  8. Analysis of rolls deflection of Sendzimir mill by 3D FEM

    YU Hai-liang; LIU Xiang-hua; LEE Gyoo Taek


    The deflection of rolls of Sendzimir mill with double AS-U-Roll was simulated by finite element method(FEM). The influences of rolling pressure, strip width and rolls-assignment on rolls deflection were analyzed. The results show that the work roll deflection increases with the increase of rolling pressure and the reduction of work roll radius, but the rigid displacement of work roll slightly changes; the work roll end might appear negative displacement for the narrow strip width and high rolling pressure that might cause the contact of work rolls. The research results are significant for guiding production and theoretical analysis of the rolls system of Sendzimir mill.

  9. Rolling Resistance and Mechanical Properties of Grinded Copper Surfaces Using Molecular Dynamics Simulation

    Liang, Shih-Wei; Wang, Chih-Hao; Fang, Te-Hua


    Mechanical properties of copper (Cu) film under grinding process were accomplished by molecular dynamics simulation. A numerical calculation was carried out to understand the distributions of atomic and slip vector inside the Cu films. In this study, the roller rotation velocity, temperature, and roller rotation direction change are investigated to clarify their effect on the deformation mechanism. The simulation results showed that the destruction of materials was increased proportionally to the roller rotation velocity. The machining process at higher temperature results in larger kinetic energy of atoms than lower temperature during the grinding process of the Cu films. The result also shows that the roller rotation in the counterclockwise direction had the better stability than the roller rotation in the clockwise direction due to significantly increased backfill atoms in the groove of the Cu film surface. Additionally, the effects of the rolling resistances on the Cu film surfaces during the grinding process are studied by the molecular dynamics simulation method.

  10. Rolling Resistance and Mechanical Properties of Grinded Copper Surfaces Using Molecular Dynamics Simulation.

    Liang, Shih-Wei; Wang, Chih-Hao; Fang, Te-Hua


    Mechanical properties of copper (Cu) film under grinding process were accomplished by molecular dynamics simulation. A numerical calculation was carried out to understand the distributions of atomic and slip vector inside the Cu films. In this study, the roller rotation velocity, temperature, and roller rotation direction change are investigated to clarify their effect on the deformation mechanism. The simulation results showed that the destruction of materials was increased proportionally to the roller rotation velocity. The machining process at higher temperature results in larger kinetic energy of atoms than lower temperature during the grinding process of the Cu films. The result also shows that the roller rotation in the counterclockwise direction had the better stability than the roller rotation in the clockwise direction due to significantly increased backfill atoms in the groove of the Cu film surface. Additionally, the effects of the rolling resistances on the Cu film surfaces during the grinding process are studied by the molecular dynamics simulation method.

  11. Backup roll contour of a SmartCrown tandem cold rolling mill

    Guanghui Yang; Jianguo Cao; Jie Zhang; Shenghui Jia; Renwei Tan


    SmartCrown was a new system developed by VAI for improving the strip profile and flatness control first applied in 1700mm tandem cold rolling mills at Wuhan Iron & Steel (Group) Corporation (WISCO). After tracing and testing, the application of the conventional crown backup roll matching the SmartCrown work roll of the production mill led to heavy and nonuniform wear, and the edge spalling of the backup roll often occurred. A 3-dimension finite element model of roll stacks was established, which was used to analyze the above-mentioned problems, and it was found that the main reason was the highly nonuniform contact pressure distribution between the work roll and the backup roll. A new FSR (flexible shape backup roll) was developed and applied in 1700mm tandem cold rolling mills. A lot of good actual effects of FSR, such as evident improvement in profile and flatness of strips,non-occurring edge spalling, wear uniform, and remarkable decrease in roll consumption were validated by long-term industrial applications.

  12. ALSTOM Schusselmuhle fur die feinvermahlung von anhydrit ALSTOM bowl mill for anhydrite fine grinding

    Angleys, M


    After the ALSTOM bowl mill had proved a success during numerous laboratory tests using different industrial minerals, for the first time a mill, type SM 20/12 was commissioned for ATLAS s.c. at Lodz /Poland for anhydrite grinding. Based on corresponding laboratory tests with anhydrite, it was possible to adapt the equipment to the requirements of the material with modified properties. Due to the project preparation together with the customer, the mill could be installed and commissioned according to schedule by a joint team of engineers for erection and commissioning.

  13. Application of multi regressive linear model and neural network for wear prediction of grinding mill liners

    Farzaneh Ahmadzadeh


    Full Text Available The liner of an ore grinding mill is a critical component in the grinding process, necessary for both high metal recovery and shell protection. From an economic point of view, it is important to keep mill liners in operation as long as possible, minimising the downtime for maintenance or repair. Therefore, predicting their wear is crucial. This paper tests different methods of predicting wear in the context of remaining height and remaining life of the liners. The key concern is to make decisions on replacement and maintenance without stopping the mill for extra inspection as this leads to financial savings. The paper applies linear multiple regression and artificial neural networks (ANN techniques to determine the most suitable methodology for predicting wear. The advantages of the ANN model over the traditional approach of multiple regression analysis include its high accuracy.


    Sonali Sen


    Full Text Available This paper utilizes acoustic parameters such as FS,NC, N, P, INC, FL, FH, W for acoustic signals S of different running conditions of a ballmill to deriveout the acoustic signatures and hence control signals, which is to be used for designing the control systems of the mill. The parameters FS, NC, N, P, INC, FL, FH and W are represented by sample rate in Hz, number of cepstral coefficients, length of frame in samples, number of filters in filter bank, frame increment, low end of the lowest filter, high end of highest filter and the window over which the analysis is to be performed respectively. The work establishes an appropriate theoretical background that helps to predict dynamic breakage characteristics with respect to particle size distribution of materials, adequately supported by experimental data. The signatures of different running conditions of grinding mill have been extracted from the captured signal in time frame these have been used as feedback signal to monitor the grinding operation. Condenser based microphones have been used for capturing acoustic signals in time domain directly in computers and stored for further analysis. Matlab R2010b has been used for different analysis of the experiment. On analyzing the signatures, it has been observed whether the fines are produced progressively to attain the desired size range or the mill producing undesired products. Thus, the approach has been used in this paper has the ability to arrive in the stage of optimum grinding by tuning parameters of the mill in real time, and also it can prevent the mill to enter into an erroneous state. Moreover, on study it has found that the present scheme can be used more accurately in comparison to the earlier work of the author. This paper presents an implementation scheme to use acoustic signal as the control signal to regulate the operation of a grinding mill.

  15. Corrosion of Cast Iron Mill Plates in Wet Grinding

    Anthony ANDREWS


    Full Text Available Corrosion studies were carried out on two different maize grinding plates. Maize was soaked in water for three days and the water decanted and used as electrolyte. Mass loss and pH measurements were carried out every 3 days for 15-day period. Results show that, for each plate, mass loss and pH increased with exposure time. Corrosion rates determined from mass loss data was found to be strongly dependent on pH. The observed behaviour may be explained in terms of the chemical composition and/or microstructures of the plates. Results are briefly discussed in terms of the contribution of corrosion to wear.

  16. Complete Mill Simulation of the Rolling Process of 1660 mm Hot Strip Continuous Mills

    Yingrui WANG; Zhenshan CUI; Yingjie WANG; Hongmin LIU


    The three-dimensional plastic deformations of strip are analyzed using the stream surface strip element method, the elastic deformations of rolls are analyzed using the influence coefficient method, the analyzing and computing model of shape and crown of 4-high mill was established by combining them, and the rolling process of 1660 mm hot strip continuous mills was simulated. The simulated results tally well with the experimental results. The model and the method for simulation of shape analysis and control of hot strip mills were provided.

  17. Experimental Study of Machinability in Mill-grinding of SiCp/Al Composites

    LI Jianguang; DU Jinguang; YAO Yingxue; HAO Zhaopeng; LIU Xiao


    An attempt was made to investigate the machinability of SiCp/Al composites based on the experimental study using mill-grinding processing method. The experiments were carried out on a high-speed CNC machining center using integrated abrasive cutting tool. The effects of combined machining parameters, e g, cutting speed (vs), feed rate (vf), and depth of cut (ap), with the same change of material removal rate (MRR) on the mill-grinding force and surface roughness (Ra) were investigated. The formation mechanism of typical machined surface defects was analyzed by SEM. The experimental results reveal that with the same change of material removal rate, lower mill-grinding force values can be gained by increasing depth of cut and feed rate simultaneously at higher cutting speed. With the same change of MRR value, lower surface roughness values can be gained by increasing the feed rate at higher cutting speed, rather than just increasing the depth of cut, or increasing the feed rate and depth of cut simultaneously. The machined surface of SiCp/Al composites reveals typical defects which can influence surface integrity.

  18. Modeling and identification of HAGC system of temper rolling mill

    HE Shang-hong; ZHONG Jue


    Including servo valve, hydraulic cylinder, mill and sensor and ignoring nonlinear factors, the linear dynamic model of hydraulic automatic gage control(HAGC) system of a temper rolling mill was theoretically derived. The order of the model is 4/4, and can be reduced to 2/2. Based on modulating functions method, utilizing numerical integration, we constructed the equivalent identification model of HAGC, and the least square estimation algorithm was established. The input and output data were acquired on line at temper rolling mill in Shangshai Baosteel Group Corporation, and the continuous time model of HAGC system was estimated with the proposed method. At different modulating window intervals, the estimated parameters changed remarkably. When the frequency bandwidth of modulating filter matches that of estimated system, the parameters can be estimated accurately. Finally, the dynamic model of the HAGC was obtained and validated based on the spectral analysis result.

  19. Optimization of Rolling Force Distribution Based on Niche Genetic Algorithm in Continuous Hot Rolling Mills

    LIU Zi-ping; LI Li-xin


    Based on the niche genetic algorithm, the intelligent and optimizing model for the rolling force distribution in hot strip mills was put forward. The research showed that the model had many advantages such as fast searching speed, high calculating pre-cision and suiting for on-line calculation. A good strip shape could be achieved by using the model and it is appropriate and practica-ble for rolling producing.

  20. A contact-type tensionmeter for hot rolling mills

    Zhao, Xiaoyan; Zhang, Zhaohui; Sun, Yikang; Wang, Jun; Que, Cheng


    To improve the hot rolled strip quality and operational stability, a novel tensionmeter based on lever principle is developed which inspects latent waves and provides real references for flatness control in hot rolling process. The contact-type tensionmeter including two segmented rolls can get the transverse tension distribution along the strip width. Tension profile is deduced by different ratio of four force values from the embedded force sensors in tensionmeter system. The compact mechanical structure ensures the tensionmeter's robust stability in hot rolling process, standard hardware and software for data acquisition make the system easy to operate and maintain. The trails have proven tensionmeter successful in improving both strip flatness and mill performance.

  1. The effect of cryogenic grinding and hammer milling on the flavour quality of ground pepper (Piper nigrum L.).

    Liu, Hong; Zeng, Fankui; Wang, Qinghuang; Ou, Shiyi; Tan, Lehe; Gu, Fenglin


    In this study, we compared the effects of cryogenic grinding and hammer milling on the flavour attributes of black, white, and green pepper. The flavour attributes were analysed using headspace solid-phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS), sensory evaluation and electronic nose (e-nose) analysis. Cryogenic grinding resulted in minimal damage to the colour, flavour, and sensory attributes of the spices. Cryogenic grinding was also better than hammer milling at preserving the main potent aroma constituents, but the concentrations of the main aroma constituents were dramatically reduced after storing the samples at 4 °C for 6 months. Pattern matching performed by the e-nose further supported our sensory and instrumental findings. Overall, cryogenic grinding was superior to hammer milling for preserving the sensory properties and flavour attributes of pepper without significantly affecting its quality. However, we found that the flavour quality of ground pepper was reduced during storage.

  2. Dimensional ranges and rolling efficiency in a tandem cold rolling mill

    Larkiola, J.


    In this work, physical models and a neural network theory have been combined in order to predict the properties of a steel strip and to optimise the process parameters in cold rolling. The prediction of the deformation resistance of the material and the friction parameter is based on the physical model presented by Bland, Ford and Ellis and artificial neural network computing (ANN). The accuracy of these models has been tested and proved by using a large amount of the measured data. With the aid of these models it has been shown that (a) the small change to the relative reduction distribution can have a clear effect upon the rolling efficiency, (b) the dimensional ranges of the tandem cold roll mill can be determined and optimised and (c) the possibility to cold roll a new product of new width, strength or thickness can be determined and the parameters of the tandem cold rolling process can be optimised. (orig.) 43 refs.

  3. Analysis of Vertical-Horizontal Coupling Vibration Characteristics of Rolling Mill Rolls Based on Strip Dynamic Deformation Process

    Dongxiao Hou


    Full Text Available Nonlinear dynamic rolling forces in the vertical and horizontal directions are, respectively, established, considering the impact of vertical and horizontal directions vibration of rolls. Then a vertical-horizontal coupling nonlinear vibration dynamic model of rolling mill rolls is proposed, based on the interactions between this dynamic rolling force and mill structure. The amplitude-frequency equations of the main resonance and inner resonance are carried out by using multiple-scale method. The characteristics of amplitude frequency under nonlinear stiffness, damping, and amplitude of the disturbance are obtained by adopting the actual parameters of 1780 rolling mills. Finally, the bifurcation behavior of the system is studied, and it is found that many dynamic behaviors such as period, period-3 motion, and chaos exist in rolling mill, and this behavior could be restrained effectively by choosing proper system parameters.

  4. Development of rolling mill for rectangular orthodontic wires production

    G.E. Totten


    Full Text Available Purpose: In orthodontic treatments, wires of different metallic alloys are used for alignment, leveling, correction of the molar position, space closing, finish and retention. The purpose of the paper is the characteristics of austenitic stainless steel wires, with a square traverse section, which were produced using a rolling mill built for this purpose, are presented hereDesign/methodology/approach: With respect to finish and retention, these wires are responsible for adequate positioning of the upper teeth on the lower teeth. Wires that are subjected to incisor torque require high resistance and stiffness. For this, wires of rectangular austenitic stainless steel are used due to high modulus of elasticity and good corrosion resistance in the oral environment. Because of the rectangular geometry, wire production requires process development suitable for industrial scale manufacture with geometric characteristics and mechanical properties better adapted to the use conditions.Findings: To obtain wires with such characteristics, a rolling mill was developed for the production of rectangular wires by a rolling process with the objective of reducing cost of the cold drawing process that is currently used which utilize complex and expensive wire-drawing dies. In addition to the rolling process itself, wire deformation, microhardness, tension and bend tests were also performed.Research limitations/implications: A rolling-mill was built that successfully produced dental wires within acceptable tolerances and physical/mechanical properties.These wires exhibited excellent hardness and tensile strength, although slightly less than analogous commercial wires. It is expected that this problem are corrected by using initial wires with a higher hardness, since this property is directly related with the tensile strength.Originality/value: In these tests, wire geometry, surface finish and mechanical properties were successfully adapted for use in orthodontic

  5. Optimize Operating Conditions on Fine Particle Grinding Process with Vertically Stirred Media Mill

    Yang, Yang; Rowson, Neil; Ingram, Andy


    Stirred media mill recently is commonly utilized among mining process due to its high stressing intensity and efficiency. However, the relationship between size reduction and flow pattern within the mixing pot is still not fully understand. Thus, this work investigates fine particle grinding process within vertically stirred media mills by altering stirrer geometry, tip speed and solids loading. Positron Emitting Particle Tracking (PEPT) technology is utilized to plot routine of particles velocity map. By tacking trajectory of a single particle movement within the mixing vessel, the overall flow pattern is possible to be plotted. Ground calcium carbonate, a main product of Imerys, is chosen as feeding material (feed size D80 30um) mixed with water to form high viscous suspension. To obtain fine size product (normally D80 approximately 2um), large amount of energy is drawn by grinding mill to break particles through impact, shear attrition or compression or a combination of them. The results indicate higher energy efficient is obtained with more dilute suspension. The optimized stirrer proves more energy-saving performance by altering the slurry circulate. Imerys Minerals Limited.

  6. Flatness Control Using Roll Coolant Based on Predicted Flatness Variation in Cold Rolling Mills

    Dohmae, Yukihiro; Okamura, Yoshihide

    Flatness control for cold rolling mills is one of the important technologies for improving of product quality and productivity. In particular, poor flatness leads to strip tearing in the extreme case and, moreover, it significantly reduces productivity. Therefore, various flatness control system has been developed. The main actuators for flatness control are classified into two types; one is mechanical equipment such as roll bender, the other is roll coolant, which controls thermal expansion of roll. Flatness variation such as center buckle or edge wave is mainly controlled by mechanical actuator which has high response characteristics. On another front, flatness variation of local zone can be controlled by roll coolant although one's response is lower than the response of mechanical actuator. For accomplishing good flatness accuracy in cold rolling mills, it is important to improve the performance of coolant control moreover. In this paper, a new coolant control method based on flatness variation model is described. In proposed method, the state of coolant spray on or off is selected to minimize the flatness deviation by using predicted flatness variation. The effectiveness of developed system has been demonstrated by application in actual plant.

  7. Rolling mill optimization using an accurate and rapid new model for mill deflection and strip thickness profile

    Malik, Arif Sultan

    This work presents improved technology for attaining high-quality rolled metal strip. The new technology is based on an innovative method to model both the static and dynamic characteristics of rolling mill deflection, and it applies equally to both cluster-type and non cluster-type rolling mill configurations. By effectively combining numerical Finite Element Analysis (FEA) with analytical solid mechanics, the devised approach delivers a rapid, accurate, flexible, high-fidelity model useful for optimizing many important rolling parameters. The associated static deflection model enables computation of the thickness profile and corresponding flatness of the rolled strip. Accurate methods of predicting the strip thickness profile and strip flatness are important in rolling mill design, rolling schedule set-up, control of mill flatness actuators, and optimization of ground roll profiles. The corresponding dynamic deflection model enables solution of the standard eigenvalue problem to determine natural frequencies and modes of vibration. The presented method for solving the roll-stack deflection problem offers several important advantages over traditional methods. In particular, it includes continuity of elastic foundations, non-iterative solution when using pre-determined elastic foundation moduli, continuous third-order displacement fields, simple stress-field determination, the ability to calculate dynamic characteristics, and a comparatively faster solution time. Consistent with the most advanced existing methods, the presented method accommodates loading conditions that represent roll crowning, roll bending, roll shifting, and roll crossing mechanisms. Validation of the static model is provided by comparing results and solution time with large-scale, commercial finite element simulations. In addition to examples with the common 4-high vertical stand rolling mill, application of the presented method to the most complex of rolling mill configurations is demonstrated

  8. Application of mechano-chemical synthesis for protective coating on steel grinding media prior to ball milling of copper

    Indranil Lahiri; K Balasubramanian


    One of the major sources of contamination during mechanical milling/alloying is from the surface erosion of the container and the grinding medium. This can either be prevented by using grinding medium and container of same material of the milled material or by adding a coating of the milled material on them. The paper describes the observations made during a mechano-chemical reaction, being used for coating the balls and vials in a planetary ball mill. Visual observation, XRD, optical micrography and EDS analysis were used to understand the progress of the reaction. Copper was successfully coated on the steel balls and vials. The method can easily be adopted in daily production purposes, prior to mechanical milling of a Cu-based powder for prevention of Fe contamination.

  9. Simulation of rolling friction in the working stands of wide-strip mills

    Garber, E. A.; Samarin, S. N.; Traino, A. I.; Ermilov, V. V.


    The energy consumed for rolling friction in the interroll contact area in the working stands of cold-rolling and pinch-pass mils intended for the production of wide steel strips has been analyzed. The coefficients and power of rolling friction are obtained for the first time using the databases of the process control systems of operating mills and simulating these quantities. A statistically reliable regression relation is obtained between the coefficient of rolling friction and the significant parameters of rolling and skin rolling (i.e., the interroll force, the roll speed, and the roll body roughness). The power fraction consumed for rolling friction is found to reach 60 80% of the total power of the main drive of working stands for skin rolling and 30 50% for cold rolling. Therefore, it is necessary to take into account these power losses in designing mills and developing technological cold-rolling conditions.

  10. Robust shape control in a sendzimir cold-rolling steel mill

    Bates, D.G.; Ringwood, J.V.; Holohan, A.M.


    The shape control problem for a Sendzimir 20-roll cold rolling steel mill is characterised by operation over a wide range of conditions arising from roll changes, changes in rolling schedules and changes in material gauge, width and hardness. Previous approaches to the problem suggest storing a larg

  11. 实用软压光辊磨削方法%Practical Grinding Method for Soft Calender Roll



    针对软压光机的软压光辊在生产使用中产生斑马纹的问题,结合材料力学的原理从软压光辊包覆材料疲劳的角度分析斑马纹的形成,分析在机使用的软压光辊表面胶层(厚度约0.2mm的疲劳破坏层、过渡层和未破坏层)的特点,阐述了在软压光辊磨削中的工艺控制方法,总结了一套软压光辊科学的磨削方法,使用该方法可延长软压光辊的在机使用寿命.%The cause of zebra grains on the soft calender roll is described to the material fatigue according to material mechanics principle. There are three outer layers of the soft calender roll, I. E. The serious damaged layer which is almost 0. 2 mm thick, the controlled grinding transition layer and the basic layer which maintains the material character. The methods for grinding these three layers are discussed. The soft calender roll grinding method including lowering down the temperature, recovery deformation, measuring, controlling the grinding amount and finishing is summarized.



    To improve roll system stability of aluminum foil mills, roll system stability of 2200 high-speed aluminum foil mill is analyzed with energy stable method.Two different restrictive conditions which gaps between chock of work roll and window of stand whether exist or not, are studied respectively.A new concept of roll system with open /closed compound pair comes up with as well for renewably synthesizing restrictive mechanism of aluminum foil mills' chock.Through these studies, the conflict, whether reserving the gap for the roller replacement or eliminating the gap for roller's normal work, is successfully settled.This concept and analyzed result give the actual mechanism with open/closed compound restriction and the method of realizing high-speed rolling and prolonging longevity of end thrust bearing on work roll.It has important theoretical meaning and engineering value for modern technical reform of aluminum foil mills and plate strip mills.

  13. a Numerical Simulation of Strip Profile in a 6-HIGH Cold Rolling Mill

    Du, Xiaozhong; Yang, Quan; Lu, Cheng; Tieu, Anh Kiet; Kim, Shinil

    Shape control is always a key issue in the six-high rolling mill, in which the shifting of the intermediate roll and the work roll have been used to enhance the shape control capability. In this paper, a finite element method (FEM) model has been developed to simultaneously simulate the strip deformation and the roll stack deformation for the six-high rolling mill. The effects of the work-roll bending, the shifting of the intermediate roll and the work roll on the strip crown and edge drop are discussed in details. Results have shown that both higher bending force and more roll shifting will significantly reduce the strip crown. The edge drop is also reduced with the bending force and the roll shifting.

  14. Reseach on Mill-grinding Experiment of Grinding Wheel with Phyllotactic Pattern%磨粒族叶序排布砂轮的铣磨实验研究

    王军; 赵良兵; 赵成义; 吕玉山


    In order to realize the ordering of the grinding wheel abrasive surface assignment, this paper combined with phyllotaxis theory and grinding mechanism, and manufactured phyllotactic pattern grinding wheel by UV lithography method and electroplating technology. The mill-grinding experiment results show that; the grinding performance of phyllotactic pattern grinding wheel is superior to what of disordered arrangement grinding wheel.%为了实现砂轮表面磨料排布的有序化,本文将仿生学叶序理论与磨削机理相结合,利用光刻技术和复合电镀技术制备出了磨粒族叶序排布砂轮.铣磨实验结果表明:磨粒族叶序排布砂轮的磨削性能优于普通无序排布砂轮.

  15. Control Strategies of Asymmetric Strip Shape in Six-High Cold Rolling Mill%Control Strategies of Asymmetric Strip Shape in Six-High Cold Rolling Mill

    ZHANG Yun; YANG Quan; WANG Xiao-chen


    It is a complicated problem for cold-rolled strip to improve asymmetric strip shape in strip production. A roll system and strip coupled model of six-high cold rolling mill was established with finite element method to estimate the effect of intermediate roll shifting, tilting, symmetric and asymmetric bending technologies on strip profile. To reduce asymmetric defects of strip shape as much as possible, some control strategies were proposed, including tilting and asymmetric bending of intermediate roll and work roll. The combinations of these three control strategies can effectively eliminate asymmetric strip shape defects. Finally, the closed-loop control model of asymmetric flat- ness at the last stand was given, and the flatness control system with the function of asymmetric strip shape control was also designed for cold tandem mill.

  16. Fragmentation mechanism of low-grade hematite ore in a high pressure grinding roll

    袁致涛; 李丽匣; 韩跃新; 刘磊; 刘廷


    The fragmentation mechanism of low-grade hematite ore in a high pressure grinding roll (HPGR) was studied based on the characteristics of comminuted products at different specific pressure levels. The major properties included the reduction ratio, liberation, specific surface energy, and specific surface area. The results showed that the fracture of low-grade hematite ore in HPGR was an interactive dynamic process in which the interaction between coarse particles of gangue minerals and fine particles of valuable minerals was alternately continuous with increased compactness and compacting strength of materials. Within a range of 2.8–4.4 N/mm2, valuable minerals were crushed after preferentially absorbing energy, whereas gangue minerals were not completely crushed and only acted as an energy transfer medium. Within a range of 4.4–5.2 N/mm2, gangue minerals were adequately crushed after absorbing the remaining energy, whereas preferentially crushed valuable minerals acted as an energy transfer medium. Within a range of 5.2–6.0 N/mm2 range, the low-grade hematite ore was not further comminuted because of the “size effect” on the strength of materials, and the comminution effect of materials became stable.

  17. Use of a finite element method to calculate roll profiles for broad-strip mills

    Garber, E. A.; Bolobanova, N. L.; Traino, A. I.


    A model is proposed to calculate the polishing profiling of rolls in broad-strip mills using a finite element method, and it is applied to develop new roll profiles. The finite element method is used to determine the polishing profiling of a roll with a complex shape, which substantially decreases the nonuniformity of reduction and drawing over the strip width. This profiling can be executed on numerical control roll grinders.

  18. Online Load Operating Mode of Oil Film Bearing in High Speed Wire Rolling Mill

    LI Yugui; PANG Siqing; HUANG Qingxue; WANG Jianmei; ZHAO Chunjiang


    To study the mechanism of burnt damage of oil film bearing in high-speed wire rolling mill, reasonable temperature sensors are designed and calibrated, pressure block of rolling mill has been transformed into pressure sensors. Online temperature and load of oil film bearing in a domestic precision rolling F15 have been tested. Consequently, a large sum of valuable test data was obtained. The distributions rules of pressure and temperature under continuous online rolling state are recorded in detail. Theoretical and experimental results are beneficial to damage mechanism of oil film bearing, thus its service life could be prolonged. Moreover, such results could provide an important reference for online test and control.

  19. Friction Coefficient Between Rolling Tube and Mandrel of Full Floating Mandrel Mill

    ZHAO Zhi-yi; XIE Jian-xin; HE Xiao-ming; DONG Kai; YU Yong; PAN Feng


    In the process of steel tube production, continuous tube rolling is the foremost forming procedure and the critical step that decides the dimension precision and the surface quality. In the actual production of the φ140 mm full floating mandrel mill in Steel Tube Branch in Baosteel, steel T91 was chosen to be the typical sample, self-made roll-ing force transducer and mandrel velocity testing equipment were used, and a series of comprehensive tests on rolling parameters including the rolling force and mandrel velocity were carried out. After the experiment, the friction state between rolling tube and mandrel was analyzed. The friction coefficient was calculated and the values of 0.033-0.074 in each mill were obtained. The friction coefficient increases obviously along the rolling direction.


    Sergio Luiz Muratori


    Full Text Available The stability of a tandem cold mill is essential to assure the thickness control, the main attribute of cold rolled steel sheets. This stability can be defined as the capability to control the process variables that act direct at the thickness. Among the most important variables are the first stand (mill linear speed and the sheet speed at the interstice ahead of it. This work shows how the chrome plated work rolls application improved this speed control and consequently the stability, which enabled an increase in the work roll rolling campaign (rolling sequence program in such a way significantly higher, compared to when using a non chrome plated work rolls. As results, significantly improvements of work rolls campaigns and the consequent increase of the equipment availability are presented.

  1. Modeling and Extended State Observer Based Dynamic Surface Control for Cold Rolling Mill System

    Xu Li


    Full Text Available The modeling and control problems are investigated for cold rolling mill system. Firstly, we establish a monitor automatic gauge control (MAGC model for a practical cold rolling mill system. The new model is with mismatched uncertainties. Then, an extended state observer (ESO is developed to estimate uncertainties. In the general high-order systems, the ESO is also used to estimate states. By dynamic surface control method, we design the controller to guarantee stabilization of the cold rolling mill system. Furthermore, we extend proposed method to general high-order systems, in which we analyze the difference from cold rolling mill system. Finally, simulation results for MAGC system are presented to demonstrate the effectiveness of the proposed control strategy.

  2. Numerical And Experimental Study On Producing Aluminum Alloy 6061 Shafts By Cross Wedge Rolling Using A Universal Rolling Mill

    Tofil A.


    Full Text Available The paper presents a selection of numerical and theoretical results of the cross wedge rolling process for producing stepped shafts made of aluminum alloy 6061. The numerical modeling was performed using the FEM-based Simufact Forming simulation software. In the simulations, we examined the kinematics of metal flow and determined the distribution patterns of effective strains, temperatures, axial stresses and the Cockroft-Latham damage criterion. Variations in the rolling forces were determined, too. The numerical results were verified experimentally using a universal rolling mill designed and constructed by the present authors. This machine can be used to perform such processes as cross wedge rolling, longitudinal rolling and round bar cropping. During the experiments, we examined process stability and finished product geometry and recorded the torques. The experimental results confirm that axisymmetric aluminum alloy shafts can be produced by cross wedge rolling with two rolls. Last but not least, the experiments served to evaluate the technological potential of the rolling mill used.

  3. Comprehensive contour prediction model of work rolls in hot wide strip mill

    Xiaodong Wang; Quan Yang; Anrui He; Renzhong Wang


    The predictive calculation of comprehensive contour of work rolls in the on-line strip shape control model during hot rolling consists of two important parts of wear contour calculation and thermal contour calculation, which have a direct influence on the accuracy of shape control. A statistical wear model and a finite difference thermal contour model of work rolls were described. The comprehensive contour is the equivalence treatment of the sum of grinding, wear, and thermal contours. This comprehensive contour calculation model has been applied successfully in the real on-line strip shape control model. Its high precision has been proved through the large amounts of actual roll profile measurements and theoretical analyses. The hit rates (percent of shape index satisfying requirement) of crown and head flatness of the strips rolled, by using the shape control model, which includes the comprehensive contour calculation model, have about 16% and 10% increase respectively, compared to those of strips rolled by using manual operation.


    Kunal Ganguly


    Full Text Available This project aims to address the problems that are facing a large aluminum company in a Developing Hot Rolling Mill Capabilities for Wider Widths Hard Alloys Rolling and b Eliminate down time due to strip /coil slippage during hard alloys 5xxx rolling at Hot Mill. The challenge for the company was to cater the fast changing export demand for Flat Rolled products with its existing resources. By applying Six Sigma principles, the team identified the current situation that the rolling mills operations were in. Si x Sigma DMAIC methodologies were use d in the project to determine the project's CTQ characteristics, defining the possible causes, Identifying the variation sources, establishing variable relationships and Implementing Control Plans. The project can be useful for any company that needs to fi nd the most cost efficient way to improve and utilize its resources.


    P.K. Pretorius


    Full Text Available

    ENGLISH ABSTRACT: Production systems have undergone dramatic changes in recent years. Many companies have implemented new technologies such as flexible manufacturing systems. There is therefore a shift in focus to maintenance and the effective management thereof. Maintenance is a dynamic activity and is comprised of a large number of interacting variables. An effective maintenance organisation is required to control these variables .
    This paper discusses the building of a maintenance organisation and the aspects that should be considered during the design. The way in which five companies that operate hot rolling mills apptoached the problem of building an effective maintenance organisation was investigated.

    AFRIKAANSE OPSOMMING: y eryaardigingstelsels het drastiese veranderinge ondergaan die afgelope aantal jaar. Verskeie Il1~atskappyemaak nou gebruik van nuwe tegnologiee, soas byvoorbeeld aanpasbare vervaardigingstelsels. Daar is gevolglik 'n verskuiwing in fokus na instandhouding en die effektiewe bestuur daarvan. lnstandhouding is 'n dinamiese aktiwiteit en behels 'n groot aantal ' gekoppelde veranderlikes. 'n Effektiewe instandhoudingsorganisasie word benodig om hierdie v'eranderlikes te beheer.
    Hierdie artikel bespreek die daarstelling van die instandhoudingsorganisasie en die parameters V~toorweeg moet word tydens die ontwerp. Die wyse waarop vyf maatskappye wat }V~rIl1walse bedryf die ontwikkeling van 'neffektiewe organisasie vir instandhouding benader hc(is ondersoek .

  6. Identification and optimization for hydraulic roll gap control in strip rolling mill

    孙杰; 陈树宗; 韩欢欢; 陈兴华; 陈秋捷; 张殿华


    In order to improve the control performance of strip rolling mill, theoretical model of the hydraulic gap control (HGC) system was established. HGC system offline identification scheme was designed for a tandem cold strip mill, the system model parameters were identified by ARX model, and the identified model was verified. Taking the offline identified parameters as the initial values, online identification using recursive least square was carried out with model parameters changing. For the purpose of improving system robustness and decreasing the sensitivity due to model errors, the HGC system based on generalized predictive control (GPC) was designed, and simulation experiments for traditional controller and GPC controller were conducted. The results show that both controllers acquire good control effect with model matching. When the model mismatches, for the traditional controller, the overshot will increase to 76.7% and the rising time will increase to 165.7 ms, which cannot be accepted by HGC system; for the GPC controller, the overshot is less than 8.5%, and the rising time is less than 26 ms in any case.

  7. Optimization of Holding Temperature and Holding Thickness for Controlled Rolling on Plate Mill

    HU Xian-lei; ZHAO Zhong; WANG Jun; WANG Zhao-dong; LIU Xiang-hua; WANG Guo-dong


    Holding temperature and holding thickness are main parameters for two-phase controlled rolling on plate mill. The optimization of holding temperature and holding thickness for pass schedule calculation of two-phase controlled rolling on plate mill was presented and its feature is as follows: (1) Determination of holding thickness can be automatically obtained based on the influence of mill safety limits, tracking zone length and holding time on holding thickness; (2) Determination of holding temperature can be automatically obtained and the holding time can be reduced as much as possible; (3) Algorithm can modify the holding temperature and thickness depending on slab size and product size.

  8. Roll wear on finishing trains of ASP1700 hot strip mills

    Zhimin Xi; Anrui He; Quan Yang; Xiaoxia Lai; Haodong Huang; Lin Zhao


    A great deal of research and practical production indicated that a perfect shape control system needs a precise prediction model of roll wear. According to the practical wear curve of work roll in Angang ASP1700 hot strip mill, which was measured by a roll-profilemeter, the model of wear curve caused by one single strip was established. The prediction of work-roll wear was achieved by combining Fortran language and practical technology parameters. The calculated results agreed well with the measured.

  9. Grinding Wear Behaviour of Stepped Austempered Ductile Iron as Media Material During Comminution of Iron Ore in Ball Mills

    Raghavendra, H.; Bhat, K. L.; Udupa, K. Rajendra; Hegde, M. M. Rajath


    An attempt has been made to evaluate the suitability of austempered ductile iron (ADI) as media material for grinding iron ore in a ball mill. Spheroidal graphite (S.G) iron balls are austenitised at 900° C for 60 minutes and given stepped austempering treatment at 280° C for 30 minutes and 60 minutes followed by 380° C for 60 minutes in each case. These materials are characterised by measuring hardness, analysing X-ray diffraction (X-RD), studying microstructure using optical and scanning electron microscope (SEM). Grinding wear behaviour of these materials was assessed for wear loss in wet condition at different pH value of the mineral slurry and found that the wear rate of grinding media material decreases with increase in pH of the slurry. The wear resistance of ADI balls were compared with forged En31 steel balls and found that the stepped austempered ductile iron is superior to forged En31 steel balls.

  10. Application of simulated annealing algorithm to improve work roll wear model in plate mills


    Employing Simulated Annealing Algorithm (SAA) and many measured data, a calculation model of work roll wear was built in the 2 800 mm 4-high mill of Wuhan Iron and Steel (Group) Co.(WISCO). The model was a semi-theory practical formula. Its pattern and magnitude were still hardly defined with classical optimization methods. But the problem could be resolved by SAA. It was pretty high precision to predict the values for the wear profiles of work roll in a rolling unit. Afterone-year application, the results show that the model is feasible in engineering, and it can be applied to predict the wear profiles of work roll in other mills

  11. Extended Kalman Filter Based Neural Networks Controller For Hot Strip Rolling mill

    Moussaoui, A. K.; Abbassi, H. A.; Bouazza, S.


    The present paper deals with the application of an Extended Kalman filter based adaptive Neural-Network control scheme to improve the performance of a hot strip rolling mill. The suggested Neural Network model was implemented using Bayesian Evidence based training algorithm. The control input was estimated iteratively by an on-line extended Kalman filter updating scheme basing on the inversion of the learned neural networks model. The performance of the controller is evaluated using an accurate model estimated from real rolling mill input/output data, and the usefulness of the suggested method is proved.

  12. High Precision Prediction of Rolling Force Based on Fuzzy and Nerve Method for Cold Tandem Mill

    JIA Chun-yu; SHAN Xiu-ying; NIU Zhao-ping


    The rolling force model for cold tandem mill was put forward by using the Elman dynamic recursive network method, based on the actual measured data. Furthermore, a good assumption is put forward, which brings a full universe of discourse self-adjusting factor fuzzy control, closed-loop adjusting, based on error feedback and expertise into a rolling force prediction model, to modify prediction outputs and improve prediction precision and robustness. The simulated results indicate that the method is highly effective and the prediction precision is better than that of the traditional method. Predicted relative error is less than ±4%, so the prediction is high precise for the cold tandem mill.

  13. Design of Fault Diagnosis Observer for HAGC System on Strip Rolling Mill

    DONG Min; LIU Cai


    By building mathematical model for HAGC (hydraulic automation gauge control) system of strip rolling mill, treating faults as unknown inputs induced by model uncertainty, and analyzing fault direction, an unknown input fault diagnosis observer group was designed. Fault detection and isolation were realized through making observer residuals robust to specific faults but sensitive to other faults. Sufficient existence conditions and design of the observers were given in detail. Diagnosis observer parameters for servo valve, cylinder, roller and body rolling mill were obtained respectively. The effectiveness of this diagnosis method was proved by actual data simulations.

  14. Soil Contamination with Heavy Metals around Jinja Steel Rolling Mills in Jinja Municipality, Uganda

    Noel Namuhani


    Conclusions. The concentration levels of heavy metals around the steel rolling mills did not appear to be of serious concern, except for copper and cadmium, which showed moderate pollution and moderate to strong pollution, respectively. All heavy metals were within the limits of the United States Environmental Protection Agency (USEPA residential soil standards and the Dutch intervention soil standards. Overall, soils around the Jinja steel rolling mills were slightly polluted with heavy metals, and measures therefore need to be taken to prevent further soil contamination with heavy metals.

  15. KDD-based rolling schedule model for plate mill

    Zhichun Mu; Dangxian Ma; Shaobo Wang; Changsong Wang


    A novel method for generating a rolling schedule is presented, which is fundamentally different from the existing ones.KDD (knowledge discovery in database) techniques are applied for discovering association rules between rolling parameters in a large database of rolling operation, and based on these rules, the schedule for the crucial last six finishing passes is generated. Operational evaluation shows that the schedule generated by the new method outperforms that generated by existing methods. It also shows how in this application the human's domain knowledge is applied to speed up the KDD process and to ensure the validity of the knowledge discovered.

  16. Prediction of Rolling Load in Hot Strip Mill by Innovations Feedback Neural Networks

    ZHANG Li-yong; WANG Jun; MA Fu-ting


    Because the structure of the classical mathematical model of rolling load is simple, even with the self-adapting technology, it is difficult to accommodate the increasing dimensional accuracy. Motivated by this fact, an Innovations Feedback Neural Networks (IFNN) was presented based on the idea of Kalman prediction. The neural networks used the Back Propagation (BP) algorithm and applied it to the prediction of rolling load in hot strip mill. The theoretical results and the off-line simulation show that the prediction capability of IFNN is better than that of normal BP networks, namely, for the prediction of the rolling load in hot strip mill, the prediction precision of IFNN is higher than that of normal BP networks. Finally, a relative complete rolling load prediction system was developed on Windows 2003/XP platform using the OOP programming method and the SQL server2000 database. With this system, the rolling load of a 1700 strip mill was calculated, and the prediction results obtained correspond well with the field data. It shows that IFNN is valid for rolling load prediction.

  17. Influences of speed of impact grinding mill and speed of classifying impeller on grinding efficiency%冲击式磨机转速和分级叶轮转速对研磨效率的影响

    王珊; 董为民; 陈国鼎


    Taking the impact grinding mill as the study objective,the paper theoretically deduced the calculation formula of maximum crushing energy and cut size of the impact grinding mill.Based on the formula of the maximum crushing energy,it analyzed the influence of the mill speed on the grinding efficiency.Meanwhile,based on the calculation formula of the cut size,it analyzed the influence of the speed of the classifying impeller on the grinding efficiency.At last,tests were conducted to verify the above influences.%以冲击式磨机为研究对象,理论推导了冲击式磨机的最大破碎能公式和切割粒径的计算公式.根据最大破碎能公式分析了冲击式磨机转速对研磨效率的影响;根据切割粒径公式分析了分级叶轮转速对研磨效率的影响,并通过试验进行了验证.

  18. Force prediction in cold rolling mills by polynomial methods

    Nicu ROMAN


    Full Text Available A method for steel and aluminium strip thickness control is provided including a new technique for predictive rolling force estimation method by statistic model based on polynomial techniques.


    Zbigniew Pater


    Full Text Available This paper deals with the issue of numerical modelling of the piercing process of a thick–walled bush in a two-rolled skew rolling mill, equipped with guiding devices of Diescher’s type. After a short characteristic of the subject matter, the developed geometric model of the process was discussed, with taking kinematics of tools movement and thermal phenomena present in metal during forming into consideration. Next, the results of calculations were presented in a form of fields of strain, damage criterion and temperature. Distributions of force parameters acting on particular tools during the process of bush rolling were also given.

  20. Control Method for Steel Strip Roughness in Two-stand Temper Mill Rolling

    LI Rui; ZHANG Qingdong; ZHANG Xiaofeng; YU Meng; WANG Bo


    How to control surface roughness of steel strip in a narrow range for a long time has become an important question because surface roughness would significantly influence the appearance of the products. However, there are few effective solutions to solve the problem currently. In this paper, considering both asperities of work roll pressing in and squeezing the steel strip, two asperity contact models including squeezing model and pressing in model in a two-stand temper mill rolling are established by using finite element method (FEM). The simulation investigates the influences of multiple process parameters, such as work roll surface roughness, roll radius and roll force on the surface roughness of steel strip. The simulation results indicate that work rolls surface roughness and roll force play important roles in the products;furthermore, the effect of roll force in the first stand is opposite to the second. According to the analysis, a control method for steel strip surface roughness in a narrow range for a long time is proposed, which applies higher work roll roughness in the first stand and lower roll roughness in the second to make the steel strip roughness in a required narrow range. In the later stage of the production, decreasing the roll force in the first stand and increasing the roll force in the second stand guarantee the steel strip roughness relatively stable in a long time. The following experimental measurements on the surface topography and roughness of the steel strips during the whole process are also conducted. The results validate the simulation conclusions and prove the effect of the control method. The application of the proposed method in the steel strip production shows excellent performance including long service life of work roll and high finished product rate.

  1. Control method for steel strip roughness in Two-stand temper mill rolling

    Li, Rui; Zhang, Qingdong; Zhang, Xiaofeng; Yu, Meng; Wang, Bo


    How to control surface roughness of steel strip in a narrow range for a long time has become an important question because surface roughness would significantly influence the appearance of the products. However, there are few effective solutions to solve the problem currently. In this paper, considering both asperities of work roll pressing in and squeezing the steel strip, two asperity contact models including squeezing model and pressing in model in a two-stand temper mill rolling are established by using finite element method (FEM). The simulation investigates the influences of multiple process parameters, such as work roll surface roughness, roll radius and roll force on the surface roughness of steel strip. The simulation results indicate that work rolls surface roughness and roll force play important roles in the products; furthermore, the effect of roll force in the first stand is opposite to the second. According to the analysis, a control method for steel strip surface roughness in a narrow range for a long time is proposed, which applies higher work roll roughness in the first stand and lower roll roughness in the second to make the steel strip roughness in a required narrow range. In the later stage of the production, decreasing the roll force in the first stand and increasing the roll force in the second stand guarantee the steel strip roughness relatively stable in a long time. The following experimental measurements on the surface topography and roughness of the steel strips during the whole process are also conducted. The results validate the simulation conclusions and prove the effect of the control method. The application of the proposed method in the steel strip production shows excellent performance including long service life of work roll and high finished product rate.

  2. Coupled dynamic modeling of rolls model and metal model for four high mill based on strip crown control

    Sun, Jianliang; Peng, Yan; Liu, Hongmin


    The crown is a key quality index of strip and plate, the rolling mill system is a complex nonlinear system, the strip qualities are directly affected by the dynamic characteristics of the rolling mil. At present, the studies about the dynamic modeling of the rolling mill system mainly focus on the dynamic simulation for the strip thickness control system, the dynamic characteristics of the strip along the width direction and that of the rolls along axial direction are not considered. In order to study the dynamic changes of strip crown in the rolling process, the dynamic simulation model based on strip crown control is established. The work roll and backup roll are considered as elastic continuous bodies and the work roll and backup roll are joined by a Winkler elastic layer. The rolls are considered as double freely supported beams. The change rate of roll gap is taken into consideration in the metal deformation, based on the principle of dynamic conservation of material flow, the two dimensional dynamic model of metal is established. The model of metal deformation provides exciting force for the rolls dynamic model, and the rolls dynamic model and metal deformation model couple together. Then, based on the two models, the dynamic model of rolling mill system based on strip crown control is established. The Newmark-β method is used to solve the problem, and the dynamic changes of these parameters are obtained as follows: (1) The bending of work roll and backup roll changes with time; (2) The strip crown changes with time; (3) The distribution of rolling force changes with time. Take some cold tandem rolling mill as subject investigated, simulation results and the comparisons with experimental results show that the dynamic model built is rational and correct. The proposed research provides effective theory for optimization of device and technological parameters and development of new technology, plays an important role to improve the strip control precision and

  3. Fuzzy-Neural Control of Hot-Rolling Mill

    Khearia Mohamad


    Full Text Available This paper deals with the application of Fuzzy-Neural Networks (FNNs in multi-machine system control applied on hot steel rolling. The electrical drives that used in rolling system are a set of three-phase induction motors (IM controlled by indirect field-oriented control (IFO. The fundamental goal of this type of control is to eliminate the coupling influence though the coordinate transformation in order to make the AC motor behaves like a separately excited DC motor. Then use Fuzzy-Neural Network in control the IM speed and the rolling plant. In this work MATLAB/SIMULINK models are proposed and implemented for the entire structures. Simulation results are presented to verify the effectiveness of the proposed control schemes. It is found that the proposed system is robust in that it eliminates the disturbances considerably.

  4. Soft Starting Arrangements Availables for Hot Rolling Mills for Energy Conservation

    Bisen, A. M.; Bapat, P. M.; Gagnuly, S. K.


    The conventional rolling mills in India are producing a major part of structural steel requirement of the country. The energy conservation in these rolling mills can be achieved mainly by reducing the size of the prime mover i.e. main electric motor. The power consumption per ton can be considerably decreased through proper selection of electric motor since it has been an observation by many surveyors[1] that the selection of electric motor of the rolling mill has been almost five to ten times on the higher side which can be easily verified from the power consumption and motor working data.Flywheel is a mechanical storage device. Largest size of flywheels are frequently recommended for smooth running of rolling mills. The main difficulty encountered in selecting large capacity flywheel or flywheel gear box system is the starting of the mill with smaller capacity electric motor. The starting characteristic of electric motor is not suitable for starting such rolling mill with very high inertia flywheel. In such condition it becomes very essential to introduce the soft starting arrangement for the electric motor so that considerably small size motor can start the flywheel effectively.Soft starters are used for the smooth start-up control of three-phase induction motors. The soft starter is functionally located between the Flywheel and the electric motor. In selecting the correct soft starter to suit the application the peculiarities of the soft start should be considered. In the prevailing conditions we use the motor of high horse power due to the fact that the flywheel requires high torque to be driven initially. For the same reason the efficiency of the flywheel is very low initially. Once the flywheel stores sufficient power which is required at the start up, the flywheel then requires less power than given initially. If we somehow are able to increase the efficiency of the flywheel using a flexible electrical, mechanical, hydraulic or flexible drives with

  5. Diagnosis of Gearbox Typical Fault in Rolling Mills Based on the Wavelet Packets Technology

    CUI Lingli; GAO Lixin; ZHANG Jianyu; DING Fang


    The early impulse fault diagnosis of the gearbox in rolling mills is often difficult and labour intensive because the gearbox of that high speed machine is multi-shafting transmission system, in which many gearsets and rolling bears work together at the same time and there are much complex frequency structure and various disturb. A new time-frequency method based on the wavelet packets technique was developed and used to extract the impact feature from signals collected from faulty data of one rolling mills gearbox. The method improves the signal to noise ration so that results obtained using this method represents features with fine resolution in both low-frequency and the high frequency bands. The results of analysis indicate the validity and the practicability of the method proposed here.

  6. Identification of Material Properties Based on Rolling Process at 4-Stand Laboratory Mill

    Szeliga, D.; Graf, M.; Kawalla, R.; Pietrzyk, M.


    The general objective of the work is to estimate the properties of the material in hot strip rolling process. The authors propose a modified inverse algorithm; to make direct use of the manufacturing process instead of conventional plastometric tests. This approach allows to reduce time and costs of identification. The rolling at 4-stand pilot mill at the Institute of Metal Forming, TU Bergakademie, Freiberg was selected. The material was C45 steel. The measured quantities of the process were rolling loads and torques, as well as temperatures. Numerical tests have shown that accuracy of torque predictions is low, therefore, the goal function of inverse analysis was defined as an average square root error between measured and FEM calculated rolling loads only. The first stage of the work was to develop the model of the hot strip rolling, which defines the direct model in the inverse analysis. This model is complex, it composes the whole roughing and finishing rolling. Based on the model and results of the laboratory experiment, the deformation process including the temperature field and the recrystallization up to the last finishing mill is calculated. Moreover, an application of the inverse analysis to the identification of the models of the hot strip rolling and design of the rolling parameters allows to obtain the required microstructure of final products. Inverse analysis and/or optimization of such a manufacturing chain is time-consuming. Large number of control parameters makes the time of the analysis unacceptable. Therefore, the metamodel of the hot rolling is applied to make the inverse calculations efficient. In the work the results of calculations with identified process parameters and experimental data are compared and presented. Also advantages and disadvantages are described.

  7. Work roll thermal contour prediction model of nonoriented electrical steel sheets in hot strip mills

    Ningtao Zhao; Jianguo Cao; Jie Zhang; Yi Su; Tanli Yan; Kefeng Rao


    The demands for profile and flatness of nonoriented electrical steels are becoming more and more severe. The temperature field and thermal contour of work rolls are the key factors that affect the profile and flatness control in the finishing trains of the hot rolling. A theoretic mathematical model was built by a two-dimensional finite difference to calculate the temperature field and thermal contour at any time within the entire rolling campaign in the hot rolling process. To improve the calculating speed and precision,some special solutions were introduced, including the development of this model, the simplification of boundary conditions, the computation of heat transfer coefficient, and the narrower mesh along the edge of the strip. The effects of rolling pace and work roll shifting on the temperature field and thermal contour of work rolls in the hot rolling process were demonstrated. The calculated results of the prediction model are in good agreement with the measured ones and can be applied to guiding profde and flatness control of nonoriented electrical steel sheets in hot strip mills.

  8. Lubricant for clean rolling: Escapee oil particles keep cold rolling steel mills lubricated

    Van De Graaf, A.


    One of the unique selling points of the Corus steel mills at IJmuiden is the quality of the steel they produce. The lubrication used during the last production stage is one of the factors that determine how clean and smooth the steel will emerge from the mill. The usual lubricant consists of an emul

  9. Assessment of personal noise exposure of overhead-traveling crane drivers in steel-rolling mills

    ZENG Lin; CHAI Dong-liang; LI Hui-juan; LEI Zhuo; ZHAO Yi-ming


    Background Noise is widespread occupational hazard in iron and steel industry. Overhead-traveling cranes are widely used in this industry, but few studies characterized the overhead-traveling crane drivers' noise exposure level so far. In this study, we assessed and characterized personal noise exposure levels of overhead-traveling crane drivers in two steel-rolling mills.Methods One hundred and twenty-four overhead-traveling crane drivers, 76 in the cold steel-rolling mill and 48 in the hot steel-rolling mill, were enrolled in the study. Personal noise dosimeters (AIHUA Instruments Model AWA5610e,Hangzhou, China) were used to collect full-shift noise exposure data from all the participants. Crane drivers carried dosimeters with microphones placed near their collars during the work shifts. Work logs had been taken by the drivers simultaneously. Personal noise exposure data were divided into segments based on lines in which they worked. All statistical analyses were done using SPSS 13.0.Results The average personal noise exposure (LAeq.8h) of overhead-traveling crane drivers in the hot steel-rolling mills ((85.03±2.25) dB(A)) was higher than that in the cold one ((83.05±2.93) dB(A), P<0.001). There were 17 overhead traveling cranes in the hot steel-rolling mill and 24 cranes in the cold one, of which carrying capacities varied from 15 tons to 100 tons. The average noise exposure level based on different lines in the hot and cold steel-rolling mills were (85.2±2.61) dB(A) and (83.3±3.10) dB(A) respectively (P=0.001), which were similar to the average personal noise exposure in both mills. The noise exposure levels were different among different lines (P=0.021).Conclusion Noise exposure levels, depending upon background noise levels and the noise levels on the ground, are inconstant. As the noise exposure levels are above the 85 dB(A) criteria, these drivers should be involved in the Hearing Conservation Program to protect their hearing.

  10. Design of Rolling State Observers for Application to Control of Thickness and Tension in Rolling Mills

    Hamid R. Koofigar


    Full Text Available This study focuses on the necessity of designing state observers to be used in controller synthesis for rolling processes. This is motivated by the fact that using several kinds of sensors for measuring all of process variables is technically and economically avoided. On the other hand, using exact measurement in feedback control systems could considerably improve the quality of products. In other word, there is a trade-off between high quality and the implementation limitations, managed here by developing rolling state observers. The proposed observers estimate the states not measured directly by the installed sensors. This technique is applicable to both hot rolling and cold rolling processes. Simulation results demonstrate the performance of the proposed estimation algorithm.

  11. Influence of a matrix on properties of mottled cast iron applied for mill rolls

    J. Krawczyk


    Full Text Available Mill rolls are ones of the most expensive tools applied in plastic working processes and have to satisfy several criteria, which allow them to be used. Cast iron mill rolls, due to their fracture toughness and tribological properties, are the most often applied at hot-rolling in the last rolling stands. This results from the smallest dynamic loads of such rolling stands and the decisive influence of the surface quality of these tools on the surface quality of the rolled product. An improper microstructure of rolls can lead to their premature wearing, e.g. broken flanges, pivots twisting off etc. By means of the heat treatment the matrix microstructure and morphology of carbide precipitationscan be modified and this in-turn can influence cast iron properties.Determination of the influence of microstructure changes, caused by the heat treatment, on the properties of EN-GJN-HV300 low-alloycast iron, after its modification and spheroidization – is the aim of the present paper. Those changes are based on the formation pearlitic or bainitic matrices at the similar morphology of graphite and ledeburitic cementite precipitations. The performed investigations should enable designing the heat treatment of cast iron metallurgical rolls in such a way as to obtain the optimal microstructures for functional parameters of these type of tools. The influence of changing the pearlitic matrix into the bainitic one on such properties as: hardness, impact strength, tensile strength, creep limit, bending strength and a stress intensity factor KIc was investigated in this study. Samples for testing, the listed above mechanical properties, were taken from an industrial casting with care to have pieces of very similar crystallization conditions.

  12. Kinetic study of ferronickel slag grinding at variation of ball filling and ratio of feed to grinding balls

    Sanwani, Edy; Ikhwanto, Muhammad


    The objective of this paper is to investigate the effect of ball filling and ratio of feed to grinding balls on the kinetic of grinding of ferronickel slag in a laboratory scale ball mill. The experiments were started by crushing the ferronickel slag samples using a roll crusher to produce -3 mesh (-6.7 mm) product. This product, after sampling and sample dividing processes, was then used as feed for grinding process. The grinding was performed with variations of ball filling and ratio of feed to grinding balls for 150 minutes. At every certain time interval, particle size analysis was carried out on the grinding product. The results of the experiments were also used to develop linear regression model of the effect of grinding variables on the P80 of the product. Based on this study, it was shown that P80 values of the grinding products declined sharply until 70 minutes of grinding time due to the dominant mechanism of impact breakage and then decreased slowly after 70 minutes until 150 minutes of grinding time due to dominant mechanism of attrition breakage. Kinetics study of the grinding process on variations of grinding ball filling showed that the optimum rate of formation of fine particles for 20%, 30%, 40% and 50% mill volume was achieved at a particle size of 400 µm in which the best initial rate of formation occurred at 50% volume of mill. At the variations of ratio of feed to grinding balls it was shown that the optimum rate of grinding for the ratio of 1:10, 1: 8 and 1: 6 was achieved at a particle size of 400 µm and for the ratio of 1: 4 was at 841 µm in which the best initial rate of formation occurred at a 1:10 ratio. In this study, it was also produced two regression models that can predict the P80 value of the grinding product as a function of the variables of grinding time, ball filling and the ratio of the feed to grinding balls.

  13. Regulation of the Heating Furnace in Tube Rolling Mill

    Kostúr, K.


    Full Text Available The rolling of tube requires homogeneous heating along the tube. In steel work the difference along tube was sometimes 80 °C. The reasons for bad homogeneousness of heating were analyzed by a simulation model of heating furnace. Then the proposal was made for a new control system and also the proposal for reconstruction of furnace. In this contribution also a description of some ways for improvement of heating was made. The main contribution is the proposal of an adaptive system

  14. Influence of the Radiation Shield on the Temperature of Rails Rolled in the Reversing Mill

    Gołdasz A.


    Full Text Available The paper presents a mathematical model of heat transfer during cooling of hot-rolled rails in the reversing mill. The influence of the radiation shield on the temperature of rolled rails has been analyzed. The heat transfer model for cooling a strip covered by the thermal shield has been presented. The two types of shields build of steel and aluminum sheets separated with insulating layer have been studded. Calculations have been performed with self developed software which utilizes the finite element method.

  15. Heavy metals adsorption on rolling mill scale; Adsorcion de metales pesados sobre cascarill de laminacion

    Lopez, F. A.; Martin, M. I.; Perez, C.; Lopez-Delgado, A.; Alguacil, E. J.


    A great quantity of industries are responsible for contaminating the environment with the heavy metals which are containing in their wastewaters. The recovery of these metals is both from an environmental and economical points of view of the upmost interest. A study is made of the use of mill scale-originating in the hot rolling of steel-as an adsorbent for the removal of heavy metals from liquid effluents. The adsorption of Zn''2+, Cd''2+ y Pb''2+ on the rolling mill scale was investigated by determination of adsorption isotherms. The effect of time, equilibrium temperature and concentration of metal solution on mill scale adsorption efficiency was evaluated. The adsorption process was analysed using the theories of Langmuir and Freundlich. Desorption process of metals from loaded mill scales was also studied using several doser bent at different experimental conditions. It has been proved that the mill scale is an effective adsorbent for the cations studies in aqueous solutions within the range of the working concentrations. (Author) 32 refs.

  16. Asymptotic Method and Numerical Analysis for Self-Excited Vibration in Rolling Mill with Clearance

    Hongguang Li


    Full Text Available In this paper, a dynamic model is proposed for analysis of nonlinear vibrations of rolling mills with fixed and time-varying clearances. Self-excited vibrations of the system that is basically involved with piece-wise nonlinearity and discontinuities are investigated via asymptotic method. It is shown by numerical results obtained for the nonlinear system with a time-varying clearance that different forms of nonlinear vibrations appear to be periodic, quasi-periodic and chaotic. Influence of the system parameters on the nonlinear vibration behaviors is examined by applying the Poincare sections, the bifurcation diagram and the largest Lyapunov exponent. New phenomena are observed in nonlinear motions of the rolling mill mechanism and are of significant importance for design of this type of mechanical systems.

  17. Preparation Model Based Control System For Hot Steel Strip Rolling Mill Stands

    Bouazza, S. E.; Abbassi, H. A.; Moussaoui, A. K.


    As part of a research project on El-hadjar Hot Steel Rolling Mill Plant Annaba Algeria a new Model based control system is suggested to improve the performance of the hot strip rolling mill process. In this paper off-line model based controllers and a process simulator are described. The process models are based on the laws of physics. these models can predict the future behavior and the stability of the controlled process very reliably. The control scheme consists of a control algorithm. This Model based Control system is evaluated on a simulation model that represents accurately the dynamic of the process. Finally the usefulness to the Steel Industry of the suggested method is highlighted.

  18. Reduced-order observer-based robust synchronisation control of cold rolling mills with measurement delay

    Jiao, Xiaohong; Mei, Zhisong


    To improve the quality of strip thickness, synchronisation control is investigated for cold rolling mills driven by dual-cylinder electro-hydraulic servo systems. Realising synchronised control in hydraulic automatic gauge control (HAGC) systems of cold rolling mills has challenges with not only the inherent nonlinearities of hydraulic servo systems and uncertainties of load variation but also measurement delay of strip thickness. Since all states are not measurable in practice, output feedback robust synchronisation control problem should be addressed for uncertain nonlinear systems with output delay. Thus, a reduced-order observer-based robust synchronous controller is presented by employing Lyapunov functional stability theory. The controller designed by incorporating the integral of the position synchronisation error of two pistons into state variables successfully guarantees asymptotic convergence to zero of both tracking errors and synchronisation error simultaneously regardless of the nonlinearities and uncertainties as well as the measurement delay. Simulation results in a model obtained from a real cold strip rolling mill demonstrate the effectiveness of the approach.

  19. Factors Roll Grinding Quality and Routine Maintenance%轧辊磨床磨削质量的影响因素及日常保养



    CNC roll grinder for the object, a brief analysis of the main factors affecting roll grinding quality, and summed up the work done by several roll grinder in daily use, and maintenance of the issues that need attention in order for the relevant job offer reference.%以数控轧辊磨床为对象,简要分析了影响轧辊磨削质量的几个主要因素,并根据工作经验总结出了几点轧辊磨床在日常使用、保养中需要注意的问题,以期为相关工作提供参考。

  20. A vision-based material tracking system for heavy plate rolling mills

    Tratnig, Mark; Reisinger, Johann; Hlobil, Helmut


    A modern heavy plate rolling mill can process more than 20 slabs and plates simultaneously. To avoid material confusions during a compact occupancy and the permanent discharging and re-entering of parts, one must know the identity and position of each part at every moment. One possibility to determine the identity and position of each slab and plate is the application of a comprehensive visual-based tracking system. Compared to a tracking system that calculates the position of a plate based on the diameter and the turns of the transport rolls, a visual system is not corrupted by a position- and material dependent transmission slip. In this paper we therefore present a vision-based material tracking system for the 2-dimensional tracking of glowing material in harsh environment. It covers the production area from the plant's descaler to the pre-stand of the rolling mill and consists of four independent, synchronized overlapping cameras. The paper first presents the conceptual design of the tracking system - and continues then with the camera calibration, the determination of pixel contours, the data segmentation and the fitting & modelling of the objects bodies. In a next step, the work will then show the testing setup. It will be described how the material tracking system was implemented into the control system of the rolling mill and how the delivered tracking data was checked on its correctness. Finally, the paper presents some results. It will be shown that the position of some moving plates was estimated with a precision of approx. 0.5m. The results will be analyzed and it will be explained where the inaccuracies come from and how they eventually can be removed. The paper ends with a conclusion and an outlook on future work.




    介绍了轧辊轴向移动轧机的发展过程、工作原理、形式特点以及在国内的应用情况,分析了目前应用最普遍的HC系列轧机的板形控制特性,并对辊系配置进行了深入的探讨。%The present paper introduces the history of development, operating principle and characteristics of the rolling mill with axial shifting roll as well as its application in the Country, analyzes the feature of the shape control for the currently most broadly applied HC rolling mill and discusses in detail the setting up of the roll system.

  2. Research upon the quality assurance of the rolling-mill rolls and the variation boundaries of the chemical composition

    Kiss, I.


    Full Text Available The cast-iron rolls must present higher hardness at the rolling surface and lower in the core and the necks, adequate with mechanical resistance and in the high work temperature. If in the zone of the rolling surface, the hardness is guarantied by the irons structure, through the cementite quantities, the core of rolls must contain graphite, to assure this property. Starting from the lamination equipments aspects, from the form of rolls, of the technological interest zones and the structure, which assures the exploitation property, it was establish, through modeling, to the mathematical description of a direct influences, and in final, through successive determinations, to an optimum. One of the parameters, which are determined the structure of the irons destined for rolls casting, is the chemical composition, which guaranties the exploitation properties of the each roll in the stand of rolling mill. The realization of optimum chemical compositions of the cast-iron can constitute a technical efficient way to assure the exploitation properties, the material from which the rolling mills rolls are manufactured having an important role in this sense. Although the manufacture of rolls is in continuously perfecting, the requirements for superior quality rolls are not yet completely satisfied, in many cases, the absence of quality rolls preventing the realization of quality laminates or the realization of productivities of which rolling mills are capable. This paper presents an analysis of the main alloying elements from chemical composition, the influences upon the mechanical properties of the cast-iron rolls, and presents also some graphical addenda. Using the Matlab calculation and graphical programs we determinate some correlations between the hardness (on the working surface and on necks and the chemical composition. Using the double and triple correlations is really helpful in the foundry practice, as it allows us to determine variation

  3. Customized maximal-overlap multiwavelet denoising with data-driven group threshold for condition monitoring of rolling mill drivetrain

    Chen, Jinglong; Wan, Zhiguo; Pan, Jun; Zi, Yanyang; Wang, Yu; Chen, Binqiang; Sun, Hailiang; Yuan, Jing; He, Zhengjia


    Fault identification timely of rolling mill drivetrain is significant for guaranteeing product quality and realizing long-term safe operation. So, condition monitoring system of rolling mill drivetrain is designed and developed. However, because compound fault and weak fault feature information is usually sub-merged in heavy background noise, this task still faces challenge. This paper provides a possibility for fault identification of rolling mills drivetrain by proposing customized maximal-overlap multiwavelet denoising method. The effectiveness of wavelet denoising method mainly relies on the appropriate selections of wavelet base, transform strategy and threshold rule. First, in order to realize exact matching and accurate detection of fault feature, customized multiwavelet basis function is constructed via symmetric lifting scheme and then vibration signal is processed by maximal-overlap multiwavelet transform. Next, based on spatial dependency of multiwavelet transform coefficients, spatial neighboring coefficient data-driven group threshold shrinkage strategy is developed for denoising process by choosing the optimal group length and threshold via the minimum of Stein's Unbiased Risk Estimate. The effectiveness of proposed method is first demonstrated through compound fault identification of reduction gearbox on rolling mill. Then it is applied for weak fault identification of dedusting fan bearing on rolling mill and the results support its feasibility.

  4. 基于正交设计的SiCp/Al复合材料铣磨力实验%Study on mill-grinding force of SiCp/Al composites by orthogonal experiment design

    都金光; 李建广; 姚英学


    To solve the problems in machining of SiCp/Al composites, experiments were carried out using electroplated diamond tool with spiral grooves for mill-grinding of SiCp/Al composites. Through the orthogonal experiments, the effects of different mill-grinding tools and processing parameters on the milling force were investigated, and the mill-grinding force was analyzed through the main effect and the variance analysis. Results showed that when mill-grinding SiCp/Al composite material, the optimal parameters combination was T2,v4, f1 and a1 , which was to say, at the processing helix angle 50°, the mill-grinding tool with three spiral grooves could get the smallest mill-grinding force in the case of processing parameters v = 314 m/min, f= 100 mm/min, a =0.01 mm. Both the normal mill-grinding force Fn and tangential mill-grinding force Ft decreased with the increase of mill-grinding speed, while increased with the increase of feed rate and mill-grinding depth. The feed rate and mill-grinding depth were found to be the highly significant factors of the normal milling force. Milling speed, feed rate and mill-grinding depth were all found to be the most effective factors of the tangential milling force. The significance of various factors on the milling force was in an order of a >f >v> Tool.%针对SiCp/Al复合材料加工中存在的问题,使用电镀金刚石螺旋槽铣磨工具对SiCp/Al复合材料进行了实验研究.通过正交实验设计,研究了不同的铣磨工具和加工参数对铣磨力的影响规律,并对实验结果进行了主效应和方差分析.结果表明:铣磨加工SiCp/Al复合材料时,最佳的参数组合为T2ν4f1a1,即使用螺旋角为50°,螺旋槽数为3的铣磨工具,在加工参数为ν=314 m/min,f=100 mm/min,a=0.01 mm下能得到较小的铣磨力;法向铣磨力Fn和切向力铣磨力Ft均随着铣磨速度的增加而减小,随着进给速度和铣磨深度的增加而增大;进给速度和铣磨深度对法向铣磨力

  5. Plate Rolling Modeling at Mill 5000 of OJSC ``Magnitogorsk Iron and Steel'' for Analysis and Optimization of Temperature Rates

    Salganik, V.; Shmakov, A.; Pesin, A.; Pustovoytov, D.


    Modeling of strip deflected mode and thermal state in rolling is an integral part of the technology and perspective rolling-mill machinery such as plate mill 5000 of the OJSC "Magnitogorsk Iron and Steel". To comprehend metal behavior in the deformation zone in the rough passes during plate rolling it is essential to assess the impact of various temperature factors on variations in field of stress and strain intensities as well as temperature fields in deformation. To do such researches in consideration of various software products and adequate results one of the most effective methods nowadays is regarded as the method of finite elements. The research shows modeling of roughing rolling of a pipe steel sheet with strength category X80 according to standard API-5L. In the research of the metal deflected mode software product DEFORM 2D has been used for the isothermal and nonisothermic process. The mathematical modeling allows revealing the impact of temperature field on the metal deflected mode in the rough passes in plate rolling. Supposedly, it is deformation heating that can have more impact on the ingot temperature profile in the finishing passes in controlled rolling of the pipe steel grades. It is defined by high percent reduction, rolling speeds; more area of heat exchange surface; less thickness and lower temperature of rolling. The results can be used to develop efficient modes of plate rolling of the pipe steels.

  6. A Fault Diagnosis Expert System for a Heavy Motor Used in a Rolling Mill


    A fault diagnosis expert system for a heavy motor used in a rolling mill is established in this paper. The fault diagnosis knowledge base was built, and its knowledge was represented by production rules. The knowledge base includes daily inspection system, brief diagnosis system and precise diagnosis system. A pull-down menu was adopted for the management of the knowledge base. The system can run under the help of expert system development tools. Practical examples show that the expert system can diagnose faults rapidly and precisely.

  7. Gauge-meter model building based on the effect of elastic deformation of rolls in a plate mill

    Xianlei Hu; Zhaodong Wang; Zhong Zhao; Xianghua Liu; Guodong Wang


    The calculation error of the gauge-meter model will affect the gap setting precision and the self-learn precision of rolling force. The precision of the gauge-meter model is strongly influenced by plate width, working roll radius, backup roll radius, working roll crown, backup roll crown, and rolling force. The influence rules are hard to get by measuring. Taking a conventional 4-h plate mill as the research subject, these influences were transferred into the calculation of roll deflection and flattening deformation. To calculate these deformations, the theory of the influence function method was adopted. By modifying the traditional gauge-meter model, a novel model of the effect of roll elastic deformation on the gap setting was built by data fitting. By this model, it was convenient to analyze the variation caused by the rolling condition. Combining the elastic deformation model of rolls with the kiss-rolls method, a gauge-meter model was put forward for plate thickness prediction. The prediction precision of thickness was greatly improved by the new gaugemeter model.

  8. Improvement of rolling modes of long length rails on the universal rail and structural steel mill “EVRAZ ZSMK”

    Golovatenko, A. V.; Umansky, A. A.; Kadykov, V. N.


    Using the results of theoretical and experimental research a new rolling mode of long-length rails on the universal rail-and-structural steel mill JSC “EVRAZ Consolidated West Siberian Metallurgical Plant” (“EVRAZ ZSMK”) was developed with a reduced number of passes in the breakdown stands. Experimental and industrial testing and implementation of the new rolling mode showed a high technical and economic efficiency of its use - reduction in the specific energy consumption was registered, as well as decrease in rejection of rails due to their surface defects, consumption of mill rolls and increase in mill productivity. The cost- effectiveness after implementation was more than 98 million RUB per year.

  9. Finger milling-cutter CNC generating hypoid pinion tooth surfaces based on modified-roll method and machining simulation

    Li, Genggeng; Deng, Xiaozhong; Wei, Bingyang; Lei, Baozhen


    The two coordinate systems of cradle-type hypoid generator and free-form CNC machine tool by application disc milling-cutter to generate hypoid pinion tooth surfaces based on the modified-roll method were set up, respectively, and transformation principle and method for machine-tool settings between the two coordinate systems was studied. It was presented that finger milling-cutter was mounted on imagined disc milling-cutter and its motion was controlled directly by CNC shafts to replace disc milling-cutter blades effective cutting motion. Finger milling-cutter generation accomplished by ordered circular interpolation was determined, and interpolation center, starting and ending were worked out. Finally, a hypoid pinion was virtually machined by using CNC machining simulation software VERICUT.

  10. 轧钢机厚度鲁棒控制策略研究%Robust Control Strategy Rolling Mill Thickness



    One of the important indicators of the quality of products for the strip thickness. In order to improve the quality of strip products, the need to strengthen the study of rolling mill thickness control system. Discusses the robust control strategy rolling mill thickness, elaborated robust control theory, and describes the rolling mill thickness control based on the robust performance analysis of the rolling mill thickness robust control strategies, hoping to provide reference and research areas relevant reference.%衡量板带产品质量的重要指标之一为厚度。为了提高板带产品的质量,需要加强对轧钢机厚度控制系统的研究。主要讨论了轧钢机厚度鲁棒控制策略,阐述了鲁棒控制理论,说明了轧钢机厚度控制基础,从鲁棒性能方面分析了轧钢机厚度鲁棒控制策略,希望能为相关研究领域提供借鉴和参考。

  11. New technology for recycling materials from oily cold rolling mill sludge

    Bo Liu; Shen-gen Zhang; Jian-jun Tian; De-an Pan; Ling Meng; Yang Liu


    Oily cold rolling mill (CRM) sludge is one of metallurgical industry solid wastes. The recycle of these wastes can not only protect the environment but also permit their reutilization. In this research, a new process of“hydrometallurgical treatment+hydrothermal synthesis”was investigated for the combined recovery of iron and organic materials from oily CRM sludge. Hydrometallurgical treatment, mainly including acid leaching, centrifugal separation, neutralization reaction, oxidizing, and preparation of hydrothermal reaction precursor, was first utilized for processing the sludge. Then, micaceous iron oxide (MIO) pigment powders were prepared through hydrothermal reaction of the obtained precursor in alkaline media. The separated organic materials can be used for fuel or chemical feedstock. The quality of the prepared MIO pigments is in accordance with the standards of MIO pigments for paints (ISO 10601-2007). This clean, eff ective, and economical technology off ers a new way to recycle oily CRM sludge.

  12. Influence of Lubrication Performance on the Service Life of Rolling Mill Bearings

    ZHOU Xiang-yang; WANG Hai-rong; JIANG Zhuang-de


    In order to confirm the early failure cause of a four-row cylindrical roller bearing at the backup roll position of a six-high cold sheet mill, its lubrication behavior under harsh operating conditions is investigated. Through establishing and solving the Elastohydrodynamic Lubrication (EHL) model of the roller-inner raceway contact region, the minimum oil film thickness and the real lubrication performance are achieved. The results show the bearing failures come from the poor oil film thickness in the case of high temperature and low rotational speed, which leads to contact wear. So various approaches to improve bearing life via improving lubrication are compared. It has been proved decreasing surface roughness of both contact bodies is an effective way.

  13. Modelling and Simulation of Three Level Inverters for Main Drive of the Plate Mill Rolling Stand

    Gasiyarov Vadim R.


    Full Text Available This paper addresses a modelling and a simulation of three level inverters for main drive of the plate mill rolling stand. The main purpose of the article is to develop of a mathematical description of the three level voltage source inverter based on a space vector pulse width modulation and to simulate a consumption current by the main electric drive based on 18-pulse rectification circuit. A twelve-megawatt synchronous motor as a load has been used. The modelling results were simulated at the Matlab/Simulink program. It can allow us to estimate an electromagnetic compatibility of the main electric drive based on transients of the consumption current. The research results can be used to assess the electromagnetic compatibility of powerful three level natural point clamped converters with different types of the space vector pulse width modulation on a load or a grid.

  14. Multicriteria FMECA Based Decision-Making for Aluminium Wire Process Rolling Mill through COPRAS-G

    Nilesh Pancholi


    Full Text Available This paper presents a multifactor decision-making approach based on “grey-complex proportional assessment (COPRAS-G method” in a view to overcome the limitations of Failure Mode Effect and Criticality Analysis (FMECA. In this model, the scores against each failure mode are expressed in grey number instead of crisp values to evaluate the criticalities of the failure modes without uncertainty. The suggested study is carried out to identify the weights of major failure causes for bearings, gears, and shafts of aluminium wire rolling mill plant. The primary findings of the paper are that sudden impact on the rolls seems to be most critical failure cause and loss of power seems to be least critical failure cause. It is suggested to modify the current control practices with proper maintenance strategy based on achieved maintainability criticality index (MCI for different failure causes. The outcome of study will be helpful in deriving optimized maintenance plan to maximize the performance of process industry.

  15. Increase of mechanical properties of hot plate due to introduction of a cycle of high-speed asymetry of work rolls on four-high mill 5000

    Severinets; I.; Y.; Kazakbaev; N.; M.; Rusakov; A.; D.; Tyapaev; O.; V.


    In the given work results of researches asymmetric rolling on reversive mill 5000 are considered.By definition of boundary modes of asymmetry and an opportunity of application results of precomputations are resulted in production for various circuits of rolling. Results of influence of asymmetric rolling on physic and mechanical properties, structure and geometry hot sheets are shown, recommendations to introduction of modes of asymmetry in a production cycle of manufacturing of sheet-rolling production of the improved quality are developed

  16. Comparison of pretreating pyrite cinder by high pressure roller grinding with damp milling to improve pelletization%高压辊磨和润磨预处理强化硫酸渣球团对比研究

    朱德庆; 陈栋; 潘建


    The pretreatment of pyrite cinder was studied using high pressure roll grinding (HPRG), which aims to improve the quality of green pellets and reinforce roasting performance of pyrite cinder pellets, and HPRG was compared with damp milling was made. The results show that both HPRG and damp milling can significantly improve green ball quality while bentonite consumption is dramatically reduced, the drop number of green balls increases from 9.0 times without pretreatment to more than 30.0 times from 0.5 m height by pretreating the pyrite cinder using HPRG and 27.4 times from 0.5 m height by using damp milling, the compressive strength increases from 7.2 N per pellet without pretreatment to 10.6 N per pellet by using HPGR to pretreat cinder and 13.7 N per pellet by using damp milling, respectively. Thermal shock temperature of green balls is above 540 ℃ and the moisture of green pellets drops by 6.5%. After the pyrite cider is pretreated by HPRG and damp milling, the preheating and roasting temperatures of the pyrite cinder pellets are decreased by 150 ℃ and 80 ℃, respectively, and the roasting time is shortened by 6 mines. Therefore, the roasting performance of pyrite cinder pellets is reinforced greatly by HPRG and damp milling. The mechanisms of HPRG and damp milling show that specific surface areas and surface energy and activity are improved, and that solid diffusion reactions are enhanced, resulting in strong bonding inside fired pellets. However, productivity of HPRG is much higher than that of damp milling, and unit energy consumption is lower than that of damp milling.%采用高压辊磨技术预处理硫酸渣改善生球质量和强化球团焙烧,并且与传统的润磨技术进行对比.研究结果表明:高压辊磨和润磨预处理硫酸渣均可大幅度提高生球质量,在膨润土用量大幅降低的同时,生球落下强度从9 0次/(0.5 m)分别增加到大于30.0次/(0.5 m)和27.4次/(0.5 m),抗压强度从7.2 N/个分别增加到10

  17. Development of Centrifugal Cast High Speed Steel Roll with High Wear Resistance for Pre-Finishing Stands of a Hot Rod-Wire Mill

    JIANG Zhi-qiang; FENG Xi-lan; FU Han-guang; SHA Quan-you


    The present study aims at developing high speed steel ( HSS ) as roll materials to replace traditional roll materials such as the alloy cast iron and powder metallurgical (PM) hard alloy, because lowcost alley cast iron rolls have poor wear resistance and the cost of high-quality PM hard alloy rolls is too high to be accepted by some users. By means of a centrifugal casting method, HSS rolls with excellent wear resistance have been developed. Its hardness is 65 ~ 67HRC, and its variation is smaller than 2HRC ; its impact toughness excels 15J/cm2. Using pre-finishing stands of a high-speed hot wire-rod rolling mill, the wear raze of HSS rolls per one thousand ton of steel is 0. 25mm. However, the manufacturing burden of HSS rolls is obviously lower than that of PM hard alloy rolls; it is only 30% of that of PM hard alloy rolls.

  18. Steel balls forming by cross rolling with upsetting

    Z. Pater


    Full Text Available The paper describes a process of forming four balls with a diameter of 22 mm by means of cross rolling with upsetting. The paper also presents the tool used to form semi-finished balls. Owing to the application of the finite element method (FEM, the course of the rolling process as well as temperature and strain distributions in the obtained balls could be presented. The rolling tests conducted in laboratory conditions at the Lublin University of Technology have proved that the balls produced with the developed rolling method meet the demands for grinding media used in ball mills.

  19. Tribological Testing of Anti-Adhesive coatings for Cold Rolling Mill Rolls—Application to TiN-Coated Rolls

    Ould, Choumad; Gachon, Yves; Montmitonnet, Pierre; Badiche, Xavier


    Roll life is a major issue in cold strip rolling. Roll wear may result either in too low roll roughness, bringing friction below the minimum requested for strip entrainment; or it may degrade strip surface quality. On the contrary, adhesive wear and transfer ("roll coating", "pick up") may form a thick metallic deposits on the roll which increases friction excessively and degrades strip surface again [1]. The roll surface, with the help of a materials-adapted lubricant, must therefore possess anti-wear and anti-adhesive properties. Thus, High Speed Steeel (HSS) rolls show superior properties compared with standard Cr-steel rolls due to their high carbide surface coverage. Another way to improve wear and adhesion properties of surfaces is to apply hard metallic (hard-Cr) or ceramic coatings. Chromium is renowned for its excellent anti-wear and anti-adhesive properties and may serve as a reference. Here, as a first step towards alternative, optimised coatings, a PVD TiN coating has been deposited on tool steels, as previous attempts have proved TiN to be rather successful in cold rolling experiments [2,3]. Different tribological tests are reported here, giving insight in both anti-adhesive properties and fatigue life improvement.

  20. Effect of Stiffness of Rolling Joints on the Dynamic Characteristic of Ball Screw Feed Systems in a Milling Machine

    Dazhong Wang


    Full Text Available Dynamic characteristic of ball screw feed system in a milling machine is studied numerically in this work. In order to avoid the difficulty in determining the stiffness of rolling joints theoretically, a dynamic modeling method for analyzing the feed system is discussed, and a stiffness calculation method of the rolling joints is proposed based on the Hertz contact theory. Taking a 3-axis computer numerical control (CNC milling machine set ermined as a research object, the stiffness of its fixed joint between the column and the body together with the stiffness parameters of the rolling joints is evaluated according to the Takashi Yoshimura method. Then, a finite element (FE model is established for the machine tool. The correctness of the FE model and the stiffness calculation method of the rolling joints are validated by theoretical and experimental modal analysis results of the machine tool’s workbench. Under the two modeling methods of joints incorporating the stiffness parameters and rigid connection, a theoretical modal analysis is conducted for the CNC milling machine. The natural frequencies and modal shapes reveal that the joints’ dynamic characteristic has an important influence on the dynamic performance of a whole machine tool, especially for the case with natural frequency and higher modes.

  1. 冷轧机张力控制系统分析%Cold Rolling Mill Tension Control System Analysis



    The stability of tension directly affects the quality of the rolled products, therefore, constant tension control rolling mill automatic control system is a key technology. Expounds the role of tension in mill production, the concept of tension, tension control and influence of the basic principles of tension fluctuation factor.%张力的稳定性直接影响着轧制产品的质量,因此,轧机的恒张力控制是轧机自动控制系统中的关键技术。主要阐述了张力在轧机生产中的作用、张力的概念、张力控制的基本原理和影响张力波动的因素。

  2. 连轧机组换辊控制系统的研究与应用%Study and Application of Roll Change Control System in Cold Tandem Rolling Mill



      介绍某1420 mm 五机架冷连轧生产线换辊控制系统的结构与控制方式。%The article describes the structure and control mode of the roll change control system for a 1420 mm five-stand cold tandem rolling mill.

  3. The Physical Flow of Materials and the Associated Costs in the Production Process of a Rolling Mill

    Holisz-Burzyńska, J.


    Full Text Available Efficiency of resources use is, in a large extent, determined by the organization of production flow and the way of their control. The optimization of materials flow in the production process requires the identification of physical flows of goods and it cost. In the article the physical flow process of materials stream in the production process in one of Polish rolling mill and also its logistics analysis and cost analysis are presented.



    The infulence of supplied pressure fluctuation on output accuracy for the electro-hydraulic pressure control system of the rolling mill is discussed.Based on the bond graph theory and experimental study,the relationship between the variation of system output pressure and the supplied pressure fluctuation and the influence of the system bandwidth on system output pressure are provided.A theoretical base for determining the allowable fluctuation range of pressure and accurate design of constant pressure source system is obtained.

  5. Genetic based sensorless hybrid intelligent controller for strip loop formation control between inter-stands in hot steel rolling mills.

    Thangavel, S; Palanisamy, V; Duraiswamy, K


    Safe operating environment is essential for all complex industrial processes. The safety issues in steel rolling mill when the hot strip passes through consecutive mill stands have been considered in this paper. Formation of sag in strip is a common problem in the rolling process. The excessive sag can lead to scrap runs and damage to machinery. Conventional controllers for mill actuation system are based on a rolling model. The factors like rise in temperature, aging, wear and tear are not taken into account while designing a conventional controller. Therefore, the conventional controller cannot yield a requisite controlled output. In this paper, a new Genetic-neuro-fuzzy hybrid controller without tension sensor has been proposed to optimize the quantum of excessive sag and reduce it. The performance of the proposed controller has been compared with the performance of fuzzy logic controller, Neuro-fuzzy controller and conventional controller with the help of data collected from the plant. The simulation results depict that the proposed controller has superior performance than the other controllers.

  6. Synchronous control for the hydraulic width system of edger rolling mill

    Ning, Shurong; Fan, Zhuoyu


    Edger rolling mill is a load system in which the upper and the lower cylinder actuate a side vertical roller at the same time. Due to the linkage of the load, the output and control of two channels influence each other. Synchronic-control issue is discussed aim to the system with serious coupling. Neural network inverse as decoupling controller is proposed to account for the complicated process dynamics characterized by nonlinear, time-varying, uncertain and load couple properties. Firstly, the reversibility of the system is analyzed and the ANN inverse dynamic is constructed based on a feed forward and neural network structure with enlarged back propagation algorithm. Secondly, the system is changed into two pseudo-linear sub-system through connecting the controlled system and inverse dynamic model in series. Aim to two pseudo-linear sub-system pole assignments method is proposed to enhance the whole system performance. A series simulation was conducted and results showed the proposed controller does better than traditional PID not only on decoupling but also on the transient response, as well as robustness under vary conditions.

  7. Investigation of the influence of the chemical composition of HSLA steel grades on the microstructure homogeneity during hot rolling in continuous rolling mills using a fast layer model

    Schmidtchen, M.; Rimnac, A.; Warczok, P.; Kozeschnik, E.; Bernhard, C.; Bragin, S.; Kawalla, R.; Linzer, B.


    The newly developed LaySiMS simulation tool provides new insight for inhomogeneous material flow and microstructure evolution in an endless strip production (ESP) plant. A deepened understanding of the influence of inhomogeneities in initial material state, temperature profile and material flow and their impact on the finished product can be reached e.g. by allowing for variable layer thickness distributions in the roll gap. Coupling temperature, deformation work and work hardening/recrystallization phenomena accounts for covering important effects in the roll gap. The underlying concept of the LaySiMS approach will be outlined and new insight gained regarding microstructural evolution, shear and inhomogeneous stress and strain states in the roll gap as well as local residual stresses will be presented. For the case of thin slab casting and direct rolling (TSDR) the interrelation of inhomogeneous initial state, micro structure evolution and dissolution state of micro alloying elements within the roughing section of an ESP line will be discussed. Special emphasis is put on the influence of the local chemical composition arising from direct charging on throughthickness homogeneity of the final product. It is concluded that, due to the specific combination of large reductions in the high reduction mills (HRM) and the highly inhomogeneous inverse temperature profile, the ESP-concept provides great opportunities for homogenizing the microstructure across the strip thickness.


    V. A. Lutsenko


    Full Text Available The quality of output production has increased in the result of new arrangement of finishing train of block construction of rod mill of RUP «BMZ». Additional using in rolled line of reducing-sizing block at production of high- carbon rolled wire enabled to reduce the dispersion of mechanical characteristics, to decrease the depth of decarburized layer.


    Willy Schuwarten Júnior


    Full Text Available A thermomechanical and a microstructure caracterization and a mathematical model of the evolution of the recrystallized volume fraction of ferrite in hot rolling in a Steckel mill have been carried out here. The proposed model is able to reasonably predict the observed in hot rolling, that is, there is 100% recrystallization of ferrite after roughing and partial recrystallization only after finishing

  10. Simulation of two Stands Cold Rolling Mill Process Using a Combination of Neural Networks and Genetic Algorithms to Avoid the Chatter Phenomenon

    Behzad BahramiNejad


    Full Text Available Rolling mill Industry is one of the most profitable industries in the world. Chatter phenomenon is one of the key issues in this industry. Chatter or rolling unwanted vibrations not only has an adverse effect on product quality, but also reduces considerably the efficiency with reduced rolling velocities of rolling lines. This paper is an attempt to simulate the phenomenon of Chatter more accurate than the previous performed simulations. In order to increase the production speed, it needs to avoid parameters which effect on the Chatter and varieties with the rolling lines condition. Actual values of these parameters were determined in the archives of the Mobarakeh two stand cold rolling mills and collected on the 210 case study of real chattering. To simulate the experiment, a neural network is trained and weights and bias values of the neural network with genetic optimization algorithm were used to get an optimal neural network which reduces bugs on the test data. So this model is capable to predict speed of Chatter threshold on rolling process of two stand cold rolling mill with the accuracy less than one percent. So it can be used in rolling process with the building intelligent recognition systems to prevent the creator conditions of the chatter frequency range.

  11. Steel strip quality upgrading through optimization of cold rolling schedules in continuous mills

    Garber; E.; Kozhevnikova; I.; Ganichev; P.; Ivoditov; V.; Traino; A.; Kuznetsov; V.


    As a result of research into the cold rolling theory and practice, a complex of mathematical models and model-based process solutions has been elaborated to improve quality of cold rolled steel strips and reduce energy consumption. The use of the above designs made it possible to establish a number of new regularities and employ them for cold rolling practice improvement and cold-rolled strip quality upgrading.

  12. Online Prediction Under Model Uncertainty via Dynamic Model Averaging: Application to a Cold Rolling Mill.

    Raftery, Adrian E; Kárný, Miroslav; Ettler, Pavel


    We consider the problem of online prediction when it is uncertain what the best prediction model to use is. We develop a method called Dynamic Model Averaging (DMA) in which a state space model for the parameters of each model is combined with a Markov chain model for the correct model. This allows the "correct" model to vary over time. The state space and Markov chain models are both specified in terms of forgetting, leading to a highly parsimonious representation. As a special case, when the model and parameters do not change, DMA is a recursive implementation of standard Bayesian model averaging, which we call recursive model averaging. The method is applied to the problem of predicting the output strip thickness for a cold rolling mill, where the output is measured with a time delay. We found that when only a small number of physically motivated models were considered and one was clearly best, the method quickly converged to the best model, and the cost of model uncertainty was small; indeed DMA performed slightly better than the best physical model. When model uncertainty and the number of models considered were large, our method ensured that the penalty for model uncertainty was small. At the beginning of the process, when control is most difficult, we found that DMA over a large model space led to better predictions than the single best performing physically motivated model. We also applied the method to several simulated examples, and found that it recovered both constant and time-varying regression parameters and model specifications quite well.

  13. Behavior of a nano-particle and a polymer molecule in a nano-scale four-roll mill

    Vo, Minh; Papavassiliou, Dimitrios


    The four-roll mill device could be used to create a mixed flow from purely extensional stresses to completely rotational through the proper selection of speed and direction of each of the four cylindrical rollers. Considerable research has been done with this device for macroscale rheological studies.. In our study, the dissipative particle dynamics (DPD) method was employed to investigate the behavior of a nano-sphere and a polymer molecule in different conditions within a four-roll mill device. Hydrophilic properties of each roll were generated by adjusting interaction parameters and using bounce back boundary condition at the solid surface. All simulations were run up to 4x106 time steps at room temperature using the open source LAMMPS package. After the flow in the system reached equilibrium, a nano-sphere and then a polymer chain were released at the center of the simulation box. Their trajectories were recorded at different shear rate conditions. The propagation of nanosphere in different rotational flow will be discussed. Additionally, the deformation of polymer chains will be compared to that in a simple shear flow.

  14. 卧式搅拌磨搅拌叶轮形状对粉碎效果的影响%Effect of Blade Shape of Horizontal Stirred Mill on Grinding Efficiency

    李茂林; 杨鑫; 崔瑞


    The effects of blade shape of horizontal stirred mill on grinding efficiency were studied. Three type of impellers were designed. The particle size and grinding capacity in same power was inspected in different stirring speed Comparing the test date, the impeller with circular holes gives the best performance on ultrafine grinding. It is the best shape of this three stirrer impellers for horizontal stirred mill on ultrafine grinding. In the energy input nearly the same circumstances,the impeller with circular holes gives the best energy utilization and yield in particle size of 1-15 u.m.%研究卧式搅拌磨的搅拌叶轮形状对磨矿效果的影响,设计3种搅拌叶轮,在不同搅拌速度的条件下,考察磨矿产品的粒度与能量新生能力.通过对比发现,3种叶轮中圆形孔叶轮的细磨效果最好,磨矿性能最优,是比较适合卧式搅拌磨机进行超细磨的搅拌叶轮形状;在能量输入基本一致的情况下,圆形孔叶轮在1~15 μm粒级能量利用率最高,产率最大.

  15. Nanostructured MgH2 Obtained by Cold Rolling Combined with Short-time High-energy Ball Milling

    Ricardo Floriano; Daniel Rodrigo Leiva; Stefano Deledda; Bjørn Christian Hauback; Walter José Botta


    MgH2 was processed by short time high-energy ball milling (BM) and cold rolling (CR). A new alternative processing route (CR + BM) using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process) resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear depen...

  16. Catalytic surface modification of roll-milled poly({epsilon}-caprolactone) biaxially stretched to ultra-thin dimension

    Foo, H.L. [Graduate Programme in Bioengineering, National University of Singapore (Singapore); Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Taniguchi, A. [Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Yu, H. [Graduate Programme in Bioengineering, National University of Singapore (Singapore); Department of Physiology, National University of Singapore (Singapore); Okano, T. [Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Institute of Biomedical Engineering, Tokyo Women' s Medical University (Japan); Teoh, S.H. [Graduate Programme in Bioengineering, National University of Singapore (Singapore) and Department of Mechanical Engineering, National University of Singapore (Singapore)]. E-mail:


    A novel roll-milling polymer processing technique along with biaxial stretching was used to fabricate 10 {mu}m thick poly({epsilon}-caprolactone) films. A less invasive collagen surface modification was used, involving a reaction between corona-preactivated membranes and ferrous-containing acrylic acid solution at the low temperature of 42 {sup o}C. Successful modified films were characterized by Toluidine Blue O assay and X-ray photoelectron spectroscopy. Human umbilical vein endothelial cells also showed both higher proliferation rate and differentiated cobblestone morphology on these collagen-immobilized substrates.

  17. Effect of hydraulic bending roll on vibration energy of a hot continuous rolling mill%液压弯辊控制参数对热连轧机振动能量影响研究

    闫晓强; 么爱东; 刘克飞


    In recent years,hot continuous rolling mill vibration problems are more prominent,many enterprises urgently need to solve this problem.Here,the vibration problem of a hot continuous rolling mill was monitored online. Then,a coupled dynamic model of a rolling mill vertical system and a hydraulic bending roll system was built.According to the actual mill parameters.MATLAB was used to do a simulation study.The effects of the control performance of the hydraulic bending rolls system on the rollers system vibration energy were analyzed by changing the controller parameters of the hydraulic bending roll system.The results provided one of effective measures for suppressing vibrations of hot continuous rolling mills.%近年来,热连轧机振动问题显得更加突出和复杂化,众多企业迫切需要解决这一难题。首先对某热连轧机振动现象进行在线监测;然后依据轧机实际参数建立液压弯辊系统和轧机垂直系统的耦合动力学模型,利用 MATLAB进行了仿真研究,通过改变液压弯辊系统中控制器参数,获得液压弯辊的控制性能对辊系振动能量的影响,实践表明这是有效抑制振动的措施之一。

  18. 基于 PFC3D的新型球磨机数值模拟研究%Study on the movement of grinding medium in ball mill based on PFC3D

    李笑同; 朴香兰


    In order to explore the ways to improve the fatigue life and the production efficiency of the ball mill,the paper established the discrete element model of the traditional ball mill and also the ball mill with variable structures.And this paper carried out an analysis and simulation of the motion of grinding medium with different rotational speeds and scale board heights to determine the position of the rotational board.Through the simulation experiments we found that the falling speed of the grinding ball in grinding chamber rose from 2 m/s to 5 m/s.This behavior could not only increase the impact force of grinding medium effectively but also avoid the limitation of improving the grinding efficiency of the traditional ball mill by changing the parameters of the quality of grinding grain and the diameter of the cylinder,etc.%为探索能够提高球磨机生产效率和延长球磨机研磨寿命的途径,利用 PFC3D 程序,建立了传统球磨机与变结构球磨机的离散元模型,针对不同转速、不同衬板高度,对磨介运动进行了仿真与分析,确定了辅助结构-旋转档板的位置。通过模拟实验发现,研磨腔内磨球的下落速度由原来的2m/s,增长到了5m/s 左右。有效地提高了磨介的冲击力,避免了传统球磨机需要通过改变研磨介质磨粒的质量和滚筒的直径等参数来提高研磨效率的局限性。

  19. 大型塔式磨机在金精矿氰化细磨中的应用%Application of Large Tower Mill in Cyanide Fine Grinding of Gold Concentrate



    Tower mill is a type of fine grinding equipment with vertical fixed installation,cylinder fixed and helical mixing device.Because gold and silver particles is fine in gold concentrate,and most of gold and silver minerals with even had body and inclusions form coexist with pyrite,fully grinding of gold concentrate is necessary in order to improve grinding fineness,make gold and silver particles fully naked,and achieve the effect of monomer dissociation.During the process of cyanide gold concentrate,due to the large increase in degree of dissociation,gold and silver are leached thoroughly,thus cyanide recovery.Tower grinding machine has the advantage of low energy consumption,grinding fine granularity,low noise,occupies less space,easy maintenance, easy installation and high grinding efficiency,therefore,it is ideal fine grinding mill in cyanide fine grinding.%塔式磨机是一种垂直安装、筒体固定及内带螺旋搅拌装置的搅拌型细磨设备。由于金精矿中金、银颗粒比较细,金、银矿物大多以连生体和包裹体形式与黄铁矿共存,需要对金精矿进行充分研磨,提高磨矿细度,使金、银颗粒充分裸露,达到单体解离的效果。在金精矿氰化过程中,解离度的大幅提高,可使金、银浸出彻底,氰化回收率随之提高。塔式磨机具有能耗低、磨矿粒度细、噪音低、占用空间少、易维护、便于安装及磨矿效率高等优点,因此是金精矿氰化细磨的理想磨机。

  20. Service behaviour of high speed steel rolling rolls used in hot strip mills; Comportamiento en servicio de los aceros rapidos utilizados en la fabricacion de los cilindros de trabajo de los trenes de bandas en caliente

    Ziadi, A.; Belzunce, F. J.; Rodriguez, C.; Fernandez, I.


    Work rolls used in hot strip mills may be able to carry out severe actions: very high thermal stresses and wear, along with mechanical stresses due to normal rolling loads, which develop in the presence of cracks, produced by the former actions. The microstructure and the mechanical behaviour (strength and toughness) of high speed steels, which recently have been introduced in this applications, were studied in this work in comparison with high chromium cast irons. (Author) 7 refs.

  1. Key technology of Zhongyue tinplate "twice rolling & once planishing" rolling mill%中粤镀锡基板“两轧一平整”机组关键技术



    The key technologies of six-rollerl 100 mm wide HC reversible cold rolling mill and four-roller 1 100 mm wide planshing mill in TMBP production line are analyzed. The key technologies of six-rollerl 100 mm wide HC reversible cold rolling mill include the thickness control, plate shape control, tention control and unoiling from plate surface. And the key technologies of four-roller 1100 mm wide planshing mill include the selection of planishing mode, tention control and surface cleaning by blowing. The application of " twice rolling & once planishing" rolling mill in the tinplate procuction is described.%分析了中山中粤镀锡基板生产线1100mm六辊可逆冷轧机和1100mm四辊平整机组的关键技术,冷轧机的厚度控制、板型控制、张力控制技术和带材表面除油技术,平整机的平整模式选择、板型控制、张力控制及表面吹扫技术等,以及两轧一平整机组在中山中粤镀锡基板生产中的应用.

  2. 斜轧中铬半钢磨球的冲击疲劳和磨损性%Impact Fatigue Resistance and Abrasiveness of Cross Rolled Medium Chromium Semi-Steel for Grinding Ball



    The repeated low-energy impact fatigue resistance and abrasiveness of cross rolled 1.85%C - 5.86%Cr medium chromium semi-steel have been studied. The results indicated that the impact fatigue life of cross rolled medium chromium semi-steel grinding ball is higher than that of casting grinding ball, and the higher impact fatigue resistance and abrasiveness of ball could be got by adequate rolled residual heat treated.%通过落球和冲击磨损试验,研究了斜轧1.85%C、5.86%Cr中铬半钢磨球的抗小能量多冲击破坏能力和耐磨性。结果表明:斜轧中铬半钢磨球的冲击疲劳寿命高于铸造半钢磨球。该球经适当的热轧余热热处理,可获得较高的抗多冲击破坏能力与耐磨性能。

  3. 三辊斜轧机轧制外螺纹管件工艺分析%Process Analysis of Rolling External-threaded Tube by Three-roll Cross Mill

    张海龙; 杨晓明; 陈端


    对采用三辊斜轧机轧制外螺纹管件的工艺过程进行了分析,特别分析了压下量、螺纹升角、送进角等工艺参数对产品质量的影响。%In this paper ,the rolling process of external-threaded pipe by three-roll cross rolling mill were analyzed ,the reduction , thread lead angle ,feed angle and other parameters influencing on product quality were put emphasis on .

  4. Gearbox fault diagnosis of rolling mills using multiwavelet sliding window neighboring coefficient denoising and optimal blind deconvolution


    Fault diagnosis of rolling mills, especially the main drive gearbox, is of great importance to the high quality products and long-term safe operation. However, the useful fault information is usually submerged in heavy background noise under the severe condition. Thereby, a novel method based on multiwavelet sliding window neighboring coefficient denoising and optimal blind deconvolution is proposed for gearbox fault diagnosis in rolling mills. The emerging multiwavelets can seize the important signal processing properties simultaneously. Owing to the multiple scaling and wavelet basis functions, they have the supreme possibility of matching various features. Due to the periodicity of gearbox signals, sliding window is recommended to conduct local threshold denoising, so as to avoid the "overkill" of conventional universal thresholding techniques. Meanwhile, neighboring coefficient denoising, considering the correlation of the coefficients, is introduced to effectively process the noisy signals in every sliding window. Thus, multiwavelet sliding window neighboring coefficient denoising not only can perform excellent fault extraction, but also accords with the essence of gearbox fault features. On the other hand, optimal blind deconvolution is carried out to highlight the denoised features for operators’ easy identification. The filter length is vital for the effective and meaningful results. Hence, the foremost filter length selection based on the kurtosis is discussed in order to full benefits of this technique. The new method is applied to two gearbox fault diagnostic cases of hot strip finishing mills, compared with multiwavelet and scalar wavelet methods with/without optimal blind deconvolution. The results show that it could enhance the ability of fault detection for the main drive gearboxes.

  5. The Research on Optimization of Edge Drop Control for Cold Tandem Rolling Mill

    Zhou, Xiao-Min; Yue, Xiao-Xue


    The cold tandem rolling of metal strip presents a significant control challenge because of nonlinearities and process complexities. And reducing edge drop of cold rolling strips and meeting uniform thickness will be a new tough shape theories and technologies. In this paper, the existing edge drop control are analyzed and optimized. The simulation results and practical data show that the optimized control system can effectively control the edge drop.

  6. Influence of rolling lubrication on the self-excited vibration of rolling mill main drive system%轧制润滑对轧机主传动系统自激振动影响

    陈程; 李友荣


    In order to research the mechanism of self-excited vibration in rolling process of F2 rolling mill production in a hot strip mill set and to eliminate the self-excited vibration of rolling mill,the main drive system of the rolling mill was simplified into two single degree of freedom systems with equal natural frequency,and the nonlinear dynamical equations of a twist vibration model of the main drive system were established.The progressive method was used to solve the nonlinear dynamical equations.The results of simulation analysis draw the following conclusions:due to the unstable rolling lubrication, the friction in rolling deformation zone declines and causes the negative damping phenomenon,resulting in the self-excited vibration of the mill.Through the field test and theoretical analysis,it is found:reasonable changes of the dynamic viscosity of rolling lubricating liquid and rolling speed can avoid the appearance of negative damping and eliminate the self-excited vibration of the mill.%为研究热连轧机组 F2轧机轧制过程中自激振动产生机理及如何消除轧机自激振动,将轧机主传动系统简化为两固有频率相同的单自由度系统建立扭振模型的非线性动力学方程。用渐进法求解非线性动力学方程。结合仿真分析表明,由于轧制变形区轧制润滑不稳定,使变形区摩擦系数下降出现负阻尼现象导致轧机产生自激振动;合理改变轧制润滑液的动力粘度及轧制速度,可避免轧制系统内产生负阻尼。

  7. 磁尺在冷连轧系统中的应用%Application of SONY Magnetic Scale in Cold Tandem Rolling Mill



      介绍磁尺在某冷连轧机组中作为 AGC 系统的位移传感器的应用方法。%The article describes how SONY Magnetic Scale works as position transducer in the AGC system of a cold tandem rolling mill.

  8. 钢坯试样铣磨床总体方案的创新设计%Innovative design for overall Scheme of milling-grinding machine for billet steel sample

    薛会民; 欧阳晶晖


    It expounds the innovative design for overall scheme of the milling-grinding machineAc-cording to the processing requirements of high efficiency and high surface quality for billet test sample,the principle scheme of machine tool was proposed based on combined innovation, which achieves a composite process of milling and grindingJn addition the grinding adopts modern belt grinding.The motion scheme of the machine tool was designed through analyzing movement functionsAs for general structure of the machine tool fixed beam gantry frame structure is adopted based on structural variation.The result indicates that the overall scheme innovation realizes the uniqueness design of the machine tool,which has good performance and can well satisfy the processing requirements of billet steel sample.%阐述了铣磨床总体方案的创新设计,针对钢坯检测试样高效率、高表面质量的加工要求,采用组合创新的方法,提出了在同一机床上实现铣削、磨削复合加工的工艺原理方案,并且机床的磨削加工采用了现代砂带磨削.通过分析机床的各种运动功能,设计了机床的运动方案.对于机床的总体结构布局,采用结构变异的方法,确定其为定梁龙门式框架结构.结果表明,通过总体方案的创新,实现了机床的独特性设计,所设计机床性能优良,很好地满足了钢坯检测试样的加工要求.

  9. Effect of Inertial Force on Thermal Elastohydrodynamic Lubrication of Oil Film Bearing in Rolling Mill Lubricated by the Oil-water Two-phase Flow

    Wang, Tao; Wang, You-Qiang; Wang, Jian; Fan, Xiao-Meng


    The oil film bearing in rolling mill as the research object in this paper is established oilwater two-phase flow of thermal elastohydrodynamic lubrication (EHL) model with the inertia force and thermal effect of the Reynolds equation. The oil film bearing in rolling mill in oil-water two-phase flow is analyzed the effect on the pyrolysis with considering inertia force, and the lubricant film pressure, film thickness with the changes in the relationship between water content, rolling force and spindle speed. The results showed that the lubricant film thickness is increased and carrying capacity is also increased with considering inertial force. With the increase of water content, lubricant film thickness is increased and the carrying capacity is decreased.


    Zhang Dazhi; Sun Yikang; Wang Yanping; Cai Hengjun


    In order to make good use of the ability to approach any function of BP (back propagation) network and overcome its local astringency,and also make good use of the overall search ability of GA (genetic algorithms),a proposal to regulate the network's weights using both GA and BP algorithms is suggested.An integrated network system of MGA (mended genetic algorithms) and BP algorithms has been established.The MGA-BP network's functions consist of optimizing GA performance parameters,the network's structural parameters,performance parameters,and regulating the network's weights using both GA and BP algorithms.Rolling forces of 4-stand tandem cold strip mill are predicted by the MGA-BP network,and good results are obtained.

  11. Using Multi-input-layer Wavelet Neural Network to Model Product Quality of Continuous Casting Furnace and Hot Rolling Mill

    HuanqinLi; JieCheng; BaiwuWan


    A new architecture of wavelet neural network with multi-input-layer is proposed and implemented for modeling a class of large-scale industrial processes. Because the processes are very complicated and the number of technological parameters, which determine the final product quality, is quite large, and these parameters do not make actions at the same time but work in different procedures, the conventional feed-forward neural networks cannot model this set of problems efficiently. The network presented in this paper has several input-layers according to the sequence of work procedure in large-scale industrial production processes. The performance of such networks is analyzed and the network is applied to model the steel plate quality of continuous casting furnace and hot rolling mill. Simulation results indicate that the developed methodology is competent and has well prospects to this set of problems.

  12. A Web-based Condition Monitoring and Diagnostic System of Rolling Mill


    A web-based condition monitoring and fault diagnosis system (CMAFDS) for the F2 finishing mill of the 2050 Hot Strip Mill was developed at a steel works. The features of the condition monitoring and fault diagnosis system based on the Web are analyzed in this paper. This paper also describes the main frame of the hardware and the software in the system and emphatically points out the function of the database management system(DBMS) based on the Web. It is proved that the web-based CMAFDS is practical in technology and much superior to the CMAFDS based on other network technology in functions.

  13. Simulation of accelerated strip cooling on the hot rolling mill run-out roller table



    Full Text Available A mathematical model of the thermal state of the metal in the run-out roller table continuous wide hot strip mill. The mathematical model takes into account heat generation due to the polymorphic γ → α transformation of supercooled austenite phase state and the influence of the chemical composition of the steel on the physical properties of the metal. The model allows calculation of modes of accelerated cooling strips on run-out roller table continuous wide hot strip mill. Winding temperature calculation error does not exceed 20°C for 98.5 % of strips of low-carbon and low-alloy steels

  14. Factors Affecting the Development of Oxide Scales on Austenitic Stainless Steels during Hot Rolling in Steckel Mills

    Cobo, S. J.; Rainforth, W. M.


    The hot rolling of austenitic stainless steels in Steckel Mills introduces particular characteristics to the development of oxides scales and surface structures. In this work, the formation of oxide structures during multipass hot rolling of 302 steel was studied under different sets of processing parameters in a laboratory system designed for the simulation of the Steckel process. The resulting surface structures were characterized by a set of complementary techniques involving scanning electron microscopy, energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and glow discharge optical spectroscopy (GDOS). The surface analysis revealed two alternative surface structures: one consisting in a thin protective oxide layer rich in Cr2O3 and the other consisting in thick complex structures containing several successive nonprotective oxide scale and metal layers resulting from a cyclic oxidation pattern involving stages of protective oxidation, chemical breakaway, and duplex oxidation. The critical condition that determined the activation of one mechanism or the other was identified associated with the parabolic rate constant for Cr2O3 growth and the diffusivity of Cr in the alloy. The effects of changes in temperature, deformation, and furnace atmosphere are discussed. Alternatives for controlling scale development are presented.

  15. Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling

    Ricardo Floriano


    Full Text Available MgH2 was processed by short time high-energy ball milling (BM and cold rolling (CR. A new alternative processing route (CR + BM using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear dependence between the size/shape of the particles which compose the starting material and the efficiency of crystallite size reduction during the BM process. On the other hand, we observed that a short BM step improved the kinetic properties of the cold rolled material. It shows that the particle size reduction of MgH2 obtained by CR combined with the increase in specific surface area attained by short BM step could be key factors to allow the use of the CR + BM route.

  16. Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling

    Ricardo Floriano


    Full Text Available MgH2 was processed by short time high-energy ball milling (BM and cold rolling (CR. A new alternative processing route (CR + BM using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear dependence between the size/shape of the particles which compose the starting material and the efficiency of crystallite size reduction during the BM process. On the other hand, we observed that a short BM step improved the kinetic properties of the cold rolled material. It shows that the particle size reduction of MgH2 obtained by CR combined with the increase in specific surface area attained by short BM step could be key factors to allow the use of the CR + BM route.

  17. CVC冷轧机承载辊缝凸度调节域计算模型%Model of CVC Cold Rolling Mill Loaded Roll Gap Crown Control Room

    李勇华; 邸洪双; 刘光明; 郝亮


    The crown control room prediction model of loaded roll gap of 4-high CVC cold rolling mill was developed.The loaded roll gap was divided into two parts, unloaded roll gap crown and deformation roll gap crown.Taking a CVC mill as an example, the model calculated result was consistent with the result that calculated by influence function method.It could be used to preset the shape crown of different actual production conditions on line.%开发了四辊CVC冷轧机承载辊缝凸度调节域预报模型,其将承载辊缝分为空载辊缝凸度与变形辊缝凸度两部分.以某厂CVC轧机为例,计算的凸度调节域与影响函数法计算的凸度调节域相吻合,可在线对不同工况下的轧机进行板凸度的预设定.

  18. "Grinding" cavities in polyurethane foam

    Brower, J. R.; Davey, R. E.; Dixon, W. F.; Robb, P. H.; Zebus, P. P.


    Grinding tool installed on conventional milling machine cuts precise cavities in foam blocks. Method is well suited for prototype or midsize production runs and can be adapted to computer control for mass production. Method saves time and materials compared to bonding or hot wire techniques.

  19. 圆弧头立铣刀端刃CNC磨削仿真技术研究%Research on CNC grinding simulation technology of torus end milling cutter's end edges

    刘建军; 黎荣; 程雪锋; 金晓波; 丁国富


    A technology on universal end edges model and CNC grinding simulation of torus end milling cutters is introduced. With the theory of space vector rotation,the universal mathematic model of end edges above center or not was builded. Based on the accurate cutting - edge model, the grinding processes of the end milling cutter end - edge rake & flank faces were researched, and also the wheel' s moving path and tool axis vector were calculated. Meanwhile, the post processing program of five-axis NC grinder and the virtual simulation environment based on VERICUT software were developed, and three kinds of end-edge models with different tooth number were geted through grinding simulation,which validated acquired cutter location data. Taking four edges end milling cutter with two edges above center as example, the grinding simulation technology proposed was verified by measuring the structure parameters of simulation model and physical model,and comparing them with design parameters.%介绍一种圆弧头立铣刀端刃的通用建模及CNC磨削仿真技术.运用空间矢量旋转原理,对过中心和不过中心端齿刃线建立通用数学模型.基于所建立的精确刃线数模,研究了立铣刀端刃前、后刀面的磨削加工工艺并计算出砂轮的运动轨迹和刀轴矢量.开发了五轴数控磨床的后置处理程序和基于VERICUT软件的虚拟仿真环境,加工出三类不同齿数的立铣刀端齿模型,对获得的刀位数据正确性进行了验证.以两齿过中心的四齿平底立铣刀为例,通过测量仿真模型和加工实物的结构参数并与设计参数进行对比,验证了提出的磨削仿真技术的可行性.

  20. Oil Film Compensation Control of Hydraulic AGC System in Tandem Cold Rolling Mill%冷连轧机液压AGC系统油膜补偿控制

    孙孟辉; 王益群


    Since the request to the quality of cold rolling sheet strips is higher, the hydraulic AGC ( Automatic Gauge Control) has become the indispensable means which improves the product precision of cold rolling strips. However, to the tandem cold rolling mill which backup roll adopts the oil film bearing, the thickness of oil film changes with different rolling force and rolling velocity, which influences the exit thickness of strips and brings the thickness deviation. Especially for the tandem cold rolling mill, the accumulative deviation of every stand enlarges more the deviation of steel product. The oil film compensation model, which adapted to the practical control, was regressed from the data measured from production locale, aiming at one 5-stand tandem cold rolling mill as object. The control strategy was brought forward, which adapted to the distributed computer control. All of them were applied in the practical rolling process for compensation of changes in thickness of oil film. The experimental result indicates that length of out-toler-ance and value of out-tolerance between head and tail of steel product are reduced notably.%由于对冷轧薄板质量要求的提高,液压AGC已经成为提高冷轧带钢成品精度必不可少的手段.然而对于支撑辊采用油膜轴承的冷连轧机来说,其轴承油膜厚度随着轧制力和轧制速度的变化而变化,这将影响轧件的轧出厚度,造成厚差.尤其对冷连轧机,各机架的累积误差会使成品带的超差更加严重.以某五机架冷连轧机为研究对象,由生产现场实测数据回归出适合于实际控制的油膜补偿模型,提出适合于分布式计算机控制的控制策略,并将其应用于实际轧制过程中对油膜厚度变化进行补偿.实验结果表明:加入油膜补偿控制后,成品带钢厚差带头带尾超差段有较为显著的减少,且超差值也有所降低.

  1. Assessment of Air Pollution and its Effects on Health of Workers of Steel Re-Rolling Mills in Hyderabad

    Altaf Alam Noonari


    Full Text Available The SRRMs (Steel Re-Rolling Mills are being releasing air pollutants in the environment. In order to evaluate their effect on the health of the workers, health and safety issues were analyzed by first measuring the concentrations of SO x (OIxides of Sulphur, NO x (Oxides of Nitrogen, CO (Carbon Monoxide and O2 (Oxygen produced in the three SRRMs located in SITE area Hyderabad. The mean concentration of SO x , NO x and CO were in the order of 0.35, 0.280, 6.333 ppm, respectively, whereas the mean concentration of O 2 was 203.53 thousand ppm. As per results, the concentration ofair pollutants, including SOx and NO x were significantly higher than to the NEQS (National Environmental Quality Standards and NAAQS (National Ambient Air Quality Standards. The concentration ofCO was lower than to the NAAQS, but higher than to the NEQs, while the concentration of O2 was slightly lower than to the standard value. The workers who were exposed to these air pollutants are being suffering from chronic diseases related to breathing and allergies. Moreover, labour staff was lifting heavy loads manually, which causes them to muscular and joint problems. In all the SRRMs under study, the electrical and mechanical equipments were used without any safety. The MSDS were not displayed on the workstations, the housekeeping was inadequate and most of the workers were performing their jobs without personal protective equipment. In addition to these, the other serious issues related to the occupational health and safety were an unhygienic supply of water, higher noise level, placement of explosive cylinders in the open atmosphere and unavailability of the first aid facilities in the Mill premises.

  2. 大棒轧线粗轧机控制系统的优化和应用%Optimization and application of stick rolling line control system for rough rolling mill



    本文主要介绍了莱钢特钢新区100吨电炉轧钢生产线粗轧机区域的概况,根据实际生产过程中的控制缺陷和不稳定因素,开始对控制进行优化。从轧制质量和控制系统稳定性出发,陆续开发了翻钢机推床自动对中功能、设备虚拟技术应用以及轧机辊缝计算模型开发等功能,提高了轧机控制系统的稳定性,提升了产品质量。%In this paper are introduced overview of rough mill of Laiwu Iron and Steel General District 100 ton electric furnace steel rolling production line area,begin to optimize the control according to the actual production process control defects and unstable factors.From the rolling quality and the stability of the control system of continue to develop the steel pusher automatic function, equipment application virtualization technology and roll seam and the function of calculating the development model,to improve the stability of the rolling mill control system,to enhance the quality of products.

  3. Pitt Mill Demonstration

    Oder, R.R.; Borzone, L.A.


    Results of a technical and economic evaluation of application of the Pitt Mill to fine coal grinding are presented. The Pitt Mill is a vertically oriented, batch operated, intermediate energy density (0. 025 kW/lb media), stirred ball mill. The mill grinds coal from coarse sizes (typically 3/16 inch or 4 mesh topsize) to the 10 micron to 20 micron mean particle diameter size range in a single step using a shallow grinding bed containing inexpensive, readily available, course grinding media. Size reduction is efficient because of rapid product circulation through the grinding bed caused by action of a novel circulation screw mounted on the agitator shaft. When a dispersant is employed, the grinding can be carried out to 50% to 60% solids concentration. Use of coarse grinding media offers the possibility of enhanced mineral liberation because size reduction is achieved more by impact shattering than by attrition. The batch method offers the possibility of very close control over product particle size distribution without overproduction of fines. A two- phase program was carried out. In the first phase, Grinding Studies, tests were run to determine a suitable configuration of the Pitt Mill. Machine design parameters which were studied included screw configuration, media type, agitator RPM, time, media size, and slurry chamber aspect ratio. During the last part of this phase of the program, tests were carried out to compare the results of grinding Pocahontas seam, Pittsburgh {number sign}8, and East Kentucky Mingo County coals by the Pitt Mill and by a two-stage grinding process employing a Netzsch John mill to feed a high energy density (0.05 kW/Lb media) disc mill. 22 refs., 25 tabs.

  4. Decoupling control based on terminal sliding mode and wavelet network for the speed and tension system of reversible cold strip rolling mill

    Fang, Yiming; Liu, Le; Li, Jianxiong; Xu, Yanze


    To weaken the nonlinear coupling influences among the variables in the speed and tension system of reversible cold strip rolling mill, a novel dynamic decoupling control strategy is proposed based on nonsingular fast terminal sliding mode (NFTSM) and wavelet neural network (WNN). First, nonlinear disturbance observers are developed to counteract the mismatched uncertainties, and then input/output dynamic decoupling and linearisation for the speed and tension nonlinear coupling system are realised by utilising the inverse system theory. Second, nonsingular fast terminal sliding mode controller (NFTSMC) for each pseudo linear subsystem is presented based on backstepping and two-power reaching law, so as to improve the global convergence speed and robust stability of the system. Third, adaptive WNNs are used to approximate the uncertain items of the system, so as to improve the control precision of the speed and tension of reversible cold strip rolling mill. Theoretical analyses show that the NFTSMs satisfy reachability condition, the system error variables can converge to equilibrium point in finite time, and the resulting closed-loop system is globally asymptotically stable. Finally, simulation research is carried out on the speed and tension system of a 1422 mm reversible cold strip rolling mill by using the actual data, and results show the superiority of the proposed control strategy in comparison with the strategies of cascade PI, linear sliding mode control and internal model control.

  5. Application and Development of Simulation Technology in Cold Continuous Rolling Mill%仿真技术在冷连轧系统的应用及发展

    崔建江; 吴胜昔; 袁枫华; 徐心和


    This paper analyses a dynamic simulation system of cold rolling mill and discusses the status and signification of simulation application and development of cold rolling mill in our country and foreign countries. Modeling and process of simulation in cold rolling mill are analysed. The execution of dynamic simulation includes the advanced modelling technology and time coordination scheduling and the use of multi-advanced simulation technology, such as coordernation simulation, simulation database, and integrated simulation. In this field virtual reality and intelligent simulation maybe act as future development in the end.%分析了一类冷连轧动态仿真系统,综述了仿真技术在冷连轧中在国内外的应用发展现状、以及发展冷连轧动态系统的意义。分析了仿真动态系统的建模及实现过程,冷连轧动态仿真的实施包含先进的模型化技术及时间协调调度,多种先进仿真技术的使用如协调仿真、仿真数据库技术一体化仿真。最后展望了该领域在虚拟现实和智能仿真技术的今后发展方向。

  6. Using Variable Perturbation Method to Study the Stability of Torsional Self-Excited Vibration in Main Drive System of Rolling Mill

    Fenglan Wang


    Full Text Available The self-excited vibration of blooming mill is a kind of torsional vibration, which occurs only when the rolling machine slips under appropriate conditions. Once in place, this may cause the larger peak pressure of each component in the main drive system; reduce the service life of the components, cause components′ damage directly. A large number of studies have shown that, at present there are not effective methods for diagnosis, monitoring of slipping and take proper measures in time to stop slipping so as to avoid the occurrence of malignant accidents. In this paper, author set out from another angle, take the main drive system of rolling mill as an example, to study stability of self-excited vibration. The conditions of the stable vibration are gained. By combining with the actual working conditions of blooming mill, author has put forward some effective measures to meet the stable conditions in order to make the blooming mill work in the stable state. Practice research has proved that the effective measures can contribute to reduce structural damage directly caused by the torsional vibration when “slipping” phenomenon occurred and to extend the service life of the components.

  7. Horizontal vibration of hot rolling mill and its relationship with rolling parameters%热连轧机水平振动及其与轧制参数影响关系

    孙建亮; 刘宏民; 李琰赟; 彭艳


    研究了热连轧机轧辊水平振动机制、水平振动与轧制过程参数间的影响关系。考虑间隙、轧辊偏移距和非线性阻尼等影响因素,建立了板带轧机工作辊水平振动非线性动力学模型,同时建立了轧机水平振动与轧制过程参数的关系模型。对某厂热连轧机F2机座进行水平振动测试试验,工作辊水平振动剧烈,中后期振幅达到4.5 g,甩尾时超过5 g,振动优势频率为40和118 Hz;同时对振动过程进行仿真,研究了轧件厚度、轧制速度和张应力参数对水平振动的影响。结果表明:仿真分析水平振动加速度幅值达到4.8 g,对比仿真和实测的振动曲线,可知仿真与实测结果相符;轧件的厚度越薄,对轧辊振动影响越大;轧制速度变化对水平振动影响较大;相比其他因素,张力对轧机水平振动的影响较小。%The horizontal vibration mechanism of hot tandem rolling mill was studied, and the relationship between the horizontal vibration and the rolling process parameters was obtained. Considering the gap between the bearing chock and the housing, the offset of work roll and backup roll, and the nonlinear damping, the nonlinear dynamic model of horizontal vibration of strip rolling mill was established, and the relationship model of horizontal vibration and rolling process param-eters was also established. Then, the online horizontal vibration test was carried out on the F2 rolling mill of some steel plant. The test result shows that the horizontal vibration of the work roll is very strong, with an amplitude up to 4.5 g in the middle and later periods and more than 5 g at the end phase, and the main vibration frequencies are 40 Hz and 118 Hz. At the same time, based on the model established, the vibration simulation in the rolling process was made to investigate the effect of strip thickness, rolling speed and tensile stress on horizontal vibration. The simulation results

  8. Improving milling and production of a dust-producing unit equipped with hammer mills

    Vorotnikov, Ye.G.; Nikiforov, A.A.; Rasputin, O.V.; Sukhunin, V.I.


    This paper presents generalized experience for deriving coarse ground coal dust in hammer mills by providing comparison data on improving efficiency of operation of the unit when switching to a coarser-type grind of the fuel. Need to have more precise formulas to calculate grinding potential of hammer mills when using a coarser grind is shown.

  9. 交流异步伺服系统在龙门刨铣磨中的应用%Application of AC asynchronous servo system in grinding-milling-planing

    张莉军; 杜宏祺


    Using time servo control system for AC induction electric planer system technology upgrade, the use of the system within the integrated PLC, pulse, encoders, digital I/O, analog I/O, communications and other interface functions, without the configuration of PC to achieve closed-loop control. In the planer on the basis of a simplified mechanical structure to achieve a grinding-milling-planing integrated. Electronic hand wheel is applied to the non-CNC machine tool feed control, to achieve precision aligning cutter during milling and grinding. Applying specific servo position control system to achieve change without switching to improve system reliability and performance of non-NC machine tools.%使用时光交流异步伺服控制系统对龙门刨电气系统进行技术升级,利用系统内部集成的PLC、脉冲、编码器、数字I/0、模拟I/O、通讯等接口功能,不需配置上位机,实现闭环控制.在对龙门刨机械结构简化的基础上,实现了刨铣磨一体.并将电子手轮应用到非数控机床的进给控制中,达到了铣、磨加工时精确对刀的要求.应用伺服系统特有的位置控制方式,实现了无开关换向,提高了系统的可靠性和非数控机床的操控性能.

  10. Study on Hydraulic Control System of Rolling Mill Based on LabVIEW%基于LabVIEW的轧钢机液压控制系统研究

    李文华; 张建卓; 李康康


    提出一种基于LabVIEW控制高速阀全开占空比,通过LabVIEW实时采集辊缝大小以作为反馈控制,同采集到的温度信号参数一起作为输入量,对轧钢机辊缝进行精确控制的思想.设计了流量控制策略与算法,并开发了LabVIEW程序框图和前面板.测试结果表明:高速阀全开过程中流过高速阀的液压油体积与实际所需的液压油体积拟合精度高,且形成了控制轧钢机辊缝的闭环控制系统.%A thought of controlling roll gap of rolling mill by controlling the duty cycle of full open of high-speed valve and collecting the roll gap as a feedback control together with the temperature signal as the input based on LabVIEW was proposed. The strategy and algorithm were designed. The LabVIEW block diagram and front panel were developed. The experiment shows that the volume of hydraulic oil flowing through the valve in the full open is closed to the practical required. And a closed-loop controlling system of controlling the roll gap of the rolling mill is formed.

  11. 热连轧机机电液耦合振动控制%Machinery-electric-hydraulic Coupling Vibration Control of Hot Continuous Rolling Mills



    全世界薄板坯连铸连轧机在轧制薄规格带钢时都出现不同程度的严重振动现象,导致带钢和轧辊生成明显振痕,从而影响企业的产品质量、外部形象和经济效益.利用自制综合遥测系统对轧机振动参数、力能参数、电参数和工艺参数等进行全面的现场综合测试,经过对测试信号的时域分析和频域分析获得振动的特征及规律;通过理论研究和仿真研究,发现轧机确实存在扭垂耦合振动、机电耦合振动和液机耦合振动现象,确定轧机振动的性质为机电液多态耦合振动.据此对电气传动控制系统和AGC系统进行参数修改和优化,将设计的二阶扭振抑制器应用在主传动控制系统中和对AGC参数进行优化,辊系振动明显降低,有效地抑制了轧机机电液耦合振动现象,取得了显著的经济效益和社会效益.%Thin slab continuous-casting and continuous-rolling mill appear different degree of serious vibration phenomenon when rolling thin strip in the world. The vibration phenomenon lead the strip and rolls to generate obvious stripe, which affects product quality and enterprise external image and economic benefits. Using self-made comprehensive telemetry system test the rolling mills vibration parameters, force and energy parameters, electric parameters and technological parameters in the site. Analysing the test signal in the time and frequency domain, characteristics and rules of vibration can be obtain. Through the theoretical and simulation research, it is found that rolling mill do exist vertical-twist coupling vibration, electro-mechanical coupling vibration and liquid-mechanical coupling vibration phenomenon. So confirming the nature of the rolling mill vibration is mechanical-electrical-liquid coupling vibration. Based on modification and optimization of the electric drive control system and AGC system, applying the designing second order torsional vibration observer in the main drive

  12. Effect of the microstructure on tribological phenomena occurring on the surface of a mill roll made of SA5T cast iron (GJSL-HV600 - GJSL-330NiMoCr12-8-3

    J. Krawczyk


    Full Text Available This paper deals with the role of the microstructure in the tribological wear processes occurring in a cast iron mill roll. For this purpose, a piece of a broken roll, made in Italy, was collected. Its microstructure consisted of modular graphite, transformed ledeburite and a matrix composed of bainite and martensite. Metallographic investigations were performed on the roll working surface in conjunction with metallographic tests effected within its surface layer. There was established the relation between the microstructure of the roll and the process of its tribological wear. The following was ascertained: micro-shrinkages or graphite precipitations nearby the working area cause cracks between those places and the working area; in the surface layer, cracks occur usually in the zone of ledeburitic cementite. At places of considerable precipitations of ledeburitic cementite, the tribological wear intensity of the roll is lower. A banded layout of precipitations of ledeburitic cementite facilitates a selective spalling of some parts of the roll material. The results of this study allow broadening the data base related to the effect of the microstructure on tribological wear of mill rolls, which in future will permit one to design their proper microstructure of cast iron mill rolls.

  13. 宽带钢热轧机CVC辊型优化与应用%Optimization and Application of CVC Roll Contour on Hot Wide Strip Mill



    In view of unreasonable of amount and distribution of work roll shifting in full stroke and short ability of crown control of F5 ~F7 mills in 2250mm hot wide strip line of Lianyuan Iron &-Steel Co. , the CVC roll contour was optimized by building models. The industry experiment shows that the work roll utilization ratio of shifting in full stroke is effectively improved, and the shape control function of work roll bending is also gotten better.%针对涟钢2250mm常规热连轧机组F5~F7机架CVC工作辊横移量及分布不合理、轧机凸度控制能力不足的问题,通过建立CVC辊型模型对其进行了优化设计.现场实验表明,CVC辊型优化后,工作辊横移全行程利用率得到了有效提高,工作辊弯辊的板形调控功效也得到了更好发挥,满足了板形控制的需要.

  14. AISI/DOE Advanced Process Control Program Vol. 3 of 6: MICROSTRUCTURAL ENGINEERING IN HOT-STRIP MILLS Part 2 of 2: Constitutive Behavior Modeling of Steels Under Hot-Rolling Conditions

    Yi-Wen Cheng; Patrick Purtscher


    This report describes the development of models for predicting (1) constitutive behaviors and (2) mechanical properties of hot-rolled steels as functions of chemical composition, microstructural features, and processing variables. The study includes the following eight steels: A36, DQSK, HSLA-V, HSLA-Nb, HSLA-50/Ti-Nb, and two interstitial-free (IF) grades. These developed models have been integrated into the Hot-Strip Mill Model (HSMM), which simulates the hot strip rolling mills and predicts the mechanical properties of hot-rolled products. The HSMM model has been developed by the University of British Columbia-Canada as a part of project on the microstructural engineering in hot-strip mills.

  15. Analysis of Roll Scale Defects of 1780 Hot Strip Mill and Guides Transformation%1780热轧辊系铁皮缺陷分析及导卫改造



    介绍了热轧辊系氧化铁皮的产生机理,分析了1780产线辊系铁皮缺陷率高的成因,通过对精轧导卫进行改造,并保证合理的氧化膜厚度等关键参数,降低了辊系铁皮的发生率。%Introduce the formation mechanism of roll scale,analyze the factor of high rate of roll scale for 1780 hot strip mill.Through transformation on roll guides of finishing mill,ensure suitable thickness of oxide film, reduce the incidence of the roll scale.

  16. Ultra-fine grinding and mechanical activation of mine waste rock using a high-speed stirred mill for mineral carbonation

    Jia-jie Li; Michael Hitch


    CO2 sequestration by mineral carbonation can permanently store CO2 and mitigate climate change. However, the cost and reaction rate of mineral carbonation must be balanced to be viable for industrial applications. In this study, it was attempted to reduce the carbonation costs by using mine waste rock as a feed stock and to enhance the reaction rate using wet mechanical activation as a pre-treatment method. Slurry rheological properties, particle size distribution, specific surface area, crystallinity, and CO2 sequestration reaction efficiency of the initial and mechanically activated mine waste rock and olivine were characterized. The results show that serpentine acts as a catalyst, in-creasing the slurry yield stress, assisting new surface formation, and hindering the size reduction and structure amorphization. Mechanically activated mine waste rock exhibits a higher carbonation conversion than olivine with equal specific milling energy input. The use of a high-speed stirred mill may render the mineral carbonation suitable for mining industrial practice.

  17. 冷连轧机辊型配置对高强钢板形控制的影响%Effect of Roll Shape Configuration of Cold Continuous Mill on High-strength Strip Profile

    吴彬; 张清东; 张晓峰


    针对薄规格高强钢板形控制困难问题,通过建立有限元模型分析了常规支撑辊+ CVC中间辊、CVC补偿支撑辊+ CVC中间辊及VCL+支撑辊+HVC中间辊3种代表性辊型配置对高强度冷轧板的板形控制能力的影响.与其他2种辊型配置方案相比,VCL+支撑辊+HVC中间辊辊型配置的承载辊缝的凸度调节域较大、横向刚度较高,辊间接触压力较小.实际生产表明,在该辊型配置方案下,高强度带钢的板形控制精度较高,支撑辊磨损得到有效改善.%To the problem of the shape of high-strength sheet difficult to control, the influences of three representative forms of roll profile configuration on high-strength strip shape control in CVC cold continuous rolling mill are compared by FEM model, which are conventional back-up roll + CVC intermediate roll, back-up roll with CVC compensation + CVC intermediate roll, VCL+ back-up roll + HVC intermediate roll. Compared with the other two roll profile configuration, the configuration of VCL+ back-up roll + HVC intermediate roll increases crown adjustment room and lateral stiffness of loaded roll gap, decreases contact pressure between rolls. The production practice shows that the control accuracy of high-strength strip shape and wear of back-up roll are improved by it.

  18. Study on five primary models in AGC system of cold rolling mill%冷轧机AGC控制系统模型研究

    王斌; 寇鹏; 窦锋


    高精度轧制技术对冷轧机液压AGC系统的控制精度提出了更高的要求,本文对AGC系统中位置控制器、伺服放大器、位移传感器、压力传感器、控制调节器五个主要模型进行分析,对模型结构中测厚仪环节、延时器环节、死区环节、限幅器环节进行数学模型分析,分析了控制系统中各种因数对控制精度的影响并选择合理的控制策略,对冷轧机液压AGC系统的优化设计及系统控制性能的研究提供了基础.%As the high-precision rolling technology has put forward a higher requirement for the control accuracy to the hydraulic AGC(automatic gauge control)system of cold rolling mill, the models of position controller, servo amplifier, displacement sensor, pressure sensor and control regulator in AGC system are investigated, and the mathematic model analysis of gauge link, delay link, dead zone link, limiter link in the model structure is performed. The influence of various factors in the control system on control accuracy is analyzed. The control strategy is selected reasonably. It is significant for designing the hydraulic AGC system of cold rolling mill and studying the response capacities of the system.

  19. Hot rolling mill horizontal-vertical coupling vibration%热连轧机横向-垂向耦合振动研究

    范小彬; 臧勇


    In order to study the vibration of a hot strip mill,according to stick-slip rolling interface friction features and the contact non-linearity between roller bearing and mill stand,the horizontal - vertical vibration model of modal coupling was established when the gap between roller bearing and mill stand appearing. It shows that when the system stiffness and the excitation frequency is in a certain section,the amplitude of horizontal and vertical vibration fluctuated sharply. So in rolling production, it should avoid this range. When the clearance appearing, the roller jump vibration occurs, roller lateral response curve has a clear cut top and its dynamic performance becomes worse.%为了研究某热连轧机组的振动特性,根据轧制界面粘滑摩擦特性和轧辊轴承座-牌坊接触非线性,建立轧辊-轴承座有无间隙时的轧辊横-垂向模态耦合振动模型.分析表明,当系统刚度和外激励频率处于某区段时轧辊横向和垂向振动幅值均出现大幅波动的现象,轧制生产中应避开此范围;机座有间隙时,轧辊出现跳振,轧辊横向响应曲线有明显的削顶现象,辊系动力学性能变差.

  20. Design of Universal Grinding Device Using in Vertical Turning and Milling Center%应用于立式车铣中心的万能磨削装置的设计

    喻鹏; 刘兴卓; 洪寿福


    The universal grinding device that using in the Vertical Turning and Milling Center was included with electric spindle and manual universal mechanism.The power supply and cooling liquid circulating system was integrated in the machine tool,with which the integrated multi-processing could be realized when the workpiece was clamped in one time.By using this device,working accuracy of machine tool is improved,and the working efficiency is improved greatly.%应用于立式车铣中心的万能磨削装置,包括电主轴及手动万能机构,其电源与冷却液循环系统集成在立式车铣中心机床上,可实现工件一次装卡,多种工序集成加工.使用该装置,提高了机床工作精度,同时大大提高了工作效率.

  1. Development and Application of Pressure-Equalizing Back-Up Roll Contour in Hot Strip Mill%宽带钢热连轧机组均压支承辊辊形开发与应用

    王晓东; 李飞; 李本海; 张宝辉; 王磊; 陈超超


    CVC(Continuous Variable Crown) work roll contour technology since its invention was applied in more than 150 hot rolling mills throughout the world for controlling strip shape.However,in actual application,there were uneven wear on rolls or even roll spalling problems because contact pressure concentrations existed between work and back-up rolls when flat or CVC back-up roll was used for configuration with CVC work roll during the rolling.For solving these defects,a pressure-equalizing back-up roll contour with combination of VCR(Variable Crown Back-up Roll) and CVC back-up roll contours was designed and applied on a hot rolling mill.It not only has the feature of VCR back-up roll contour,but also can improve the contact condition between work and back-up roll.After the application of pressure-equalizing back-up roll contour,roll spalling problem was solved,and strip profile quality was also improved.%CVC工作辊辊形自发明以来在全球150多条热连轧生产线上得到应用,以控制带钢的板形。实际应用中,与CVC工作辊配对使用的支承辊无论采用平辊还是CVC辊形均存在非均匀磨损甚至轧辊剥落失效的问题,主要原因是CVC支承辊辊形和平支承辊与CVC工作辊配置时存在接触压力集中。为了解决此问题,设计并应用了一种均压支承辊辊形与CVC工作辊配置使用。此辊形是变接触支承辊辊形(VCR)与CVC支承辊辊形的组合,具有变接触辊形的优点,同时又能更好地与CVC工作辊配置使用。均压支承辊辊形应用后,改善了CVC工作辊与支承辊辊间接触状态,解决了轧辊剥落问题,并改善了带钢凸度质量。

  2. Development of the speed control unit of the hot rolling mill of the brazilian National Steel Company; Desenvolvimento do controle de correcao de velocidade do acabamento do LTQ-2 da CSN

    Silveira, Aquiles A. da; Dornelas, Francisco C.; Ferreira, Emerson R.; Alves, Sergio C.; Miguez, Antonio C.P.; Brandao, Jose M.M.; Tirello, Jonas [Companhia Siderurgica Nacional, Volta Redonda, RJ (Brazil)


    This work shows the development of a control system to correct the speed of the tandem hot rolling mill, by utilization of a mathematical model. A more reliable operational performance was reached with the application of this model at a computer set-up level. 4 figs.

  3. Planejamento e controle da produção de cilindros para laminação: um estudo de caso quantitativo Production management of rolling mill rolls: a quantitative study case

    Laerte José Fernandes


    Full Text Available Este trabalho apresenta um modelo de otimização-simulação aplicado em um estudo de caso real no setor de cilindros para laminação de uma siderúrgica, buscando melhorar o gerenciamento da área/equipamento gargalo da linha de produção. A simulação atuou em conjunto com um modelo de otimização da programação linear inteira (PLI para melhorar o atendimento de prazo junto aos clientes em uma produção não seriada. Como resultado deste procedimento combinado da PLI e simulação, o processo produtivo foi otimizado e as filas de espera e o lead-time foram reduzidos, melhorando o atendimento aos clientes.This article presents a simulation-optimization model application for a real case study in the rolling mill roll sector of a steel plant. The purpose of this study was to get a better area/equipment bottleneck management in the production line. The simulation was used together with an ILP (Integer Linear Programming optimization model, in order to improve customer service in a made-to-order production. As a result of this ILP and Simulation combined approach, the productive process was optimized and both queues and lead-time were reduced, improving customer service.

  4. Simulating AGC Hydraulic System of Single-stand Cold Rolling Mill%单机架冷轧机 AGC 液压系统仿真

    吴中友; 陈举庆


    Hopsan Hydraulic Simulation software is used to model and simulate AGC hydraulic system of a 1250mm single-stand cold rolling mill to compare the difference and connection between the position loop and force loop of the control system. With this simulation, the factor that effects the function of AGC hydraulic systems can be analyzed.%  采用 Hopsan 液压仿真软件对某1250 mm 单机架可逆冷轧机 AGC 液压系统建模仿真,比较位置环与力环控制系统的差异和联系,对影响 AGC 液压系统性能的因素进行分析。

  5. 轧机换辊车传动方式改进设计%Improvement Design for the Transmission Mode of the Roll Change Carriage in Rolling Mill

    王华勇; 周晓艳


    The defects of the old transmission mode is analyzed ,the force analysis of the gear in reduction box is analyzed and the troque of the old mode is calculated .According to these analysis,the old transmission mode should be changed to hydraulic motor.It is proved that this improvement could reduce the failure rate and shorten the roll changing time effectively.%针对换辊车原设计传动方式的不足,改变原有传动方式,通过对减速箱齿轮的受力分析,计算出原传动所提供的扭矩,将减速电机更换为液压马达,生产实践证明,此改进可降低设备故障率,缩短换辊时间。


    Hu Huiqing


    The grinding of two parallel sides of a component is accomplished with the accuracy and higher productivity by passing a blank through the truncated cone shape grinders, which are turned angles. The machine is designated by the name of double disc grinding machine (DDGM). Usually, it is used in the mass production. The relationship between these angles, the accuracy, productivity,allowance and parameters of the machine and technology is explained in detail by math, such as vector analysis, transformation of 3D space coordinates, etc. Therefore, in the aspects of qualitative and quantitative analyses, the grinding potential of DDGM is enormous increased and superior to conventional methods. Furthermore, the theoretical foundation of DDGM grinding design and technology is provided to improve, to expand and to create for future. The established machine design and practical experience of grinding technology will get great benefit by them.

  7. Analysis on vibration factors of main drive system of CSP hat rolling mill%CSP轧机主传动系统致振因素的分析

    吴继民; 吴炳胜


    The main drive system of CSP rolling mill abnormal vibration phenomena was analyzed to determine the causes of the vibration. At first, it was found that the mechanical gaps of the main drive system had a great impact on twist vibration of system, and then the rolling interface changes due to rolling torque on the vibration impact was analyzed. The MATLAB/Simulink software was used to simulate the rolling torque. The results show that the fluctuation of the rolling torque has a immediate impact on the vibration of the main drive system. The fluctuation of the friction coefficient impacting the main drive system vibration is due to the stead-state self-excited torsional vibration produced to the main drive system. By analyzing the electrical parameters controlled by the inverter and the main drive system torsional vibration impact, it concludes that the harmonics torque is generated by the electromagnetic harmonics, so that the main drive system can produce the torsional response. At last, a series of measures on the theoretical basis to inhibit the abnormal vibration were provides.%对CSP轧机主传动系统异常振动现象进行分析,为了确定引起振动的原因,分析了主传动系统机械间隙的存在对振动产生的影响,以及轧制界面因轧制力矩的变化对振动产生影响.通过MATLAB的Simulink软件对轧制力矩进行仿真发现,轧制力矩的波动对主传动系统振动的产生有直接影响;摩擦系数的波动对主传动系统振动产生的影响,是对主传动系统产生稳态的自激扭转振动;在对变频器控制的电气参数与主传动系统扭振的影响分析得出,由电磁谐波产生的谐波转矩,使主传动系统产生相应的扭振响应.最后在理论上提出了一系列抑制振动的措施.


    S.K. GARG


    Full Text Available Grinding is a unit operation to break big solid material into smaller pieces. As far as process of grinding is concerned, power consumption, specific energy consumption and particle size distribution and mill capacity are main considerations from engineering point of view. The experiments were conducted to study the effect of speed of mill, sieve size, feed rate and time of grinding on power consumption and average particle diameter of water chestnut in continuous grinding process. Power consumption was measured for a constant feed rate of 1 and 2 kg/h at different speed of the mill varied from 800 to 1200 rpm for the sieve openings of 0.5 mm, 1.0 mm and 2.0 mm. For all the sieve sizes and feed rates, it was observed that as the speed of the mill increases, there is an increase in power consumption and found significantly low for higher sieve size and lower feed rate. The size distribution of the water chestnut kernel for different speeds and sieve sizes at constant feed rate were obtained by sieve analysis. The milling speed has no significant effect on particle size distribution of ground product and mass fraction was minimum at lower feed rate and higher sieve size. Harris model was found best suitable to describe the size distribution in continuous grinding process. Fineness modulus decreases with increase of milling speed for experimental sieve size and feed rate.

  9. 冷带轧机液压AGC系统过程优化级计算机控制%Research on Computer Control of Process Optimization Level in Hydraulic AGC System of Cold Rolling Mill

    孙孟辉; 王益群


    冷带轧机的轧制过程是较为复杂的物理过程,因此液压AGC(Automatic Gauge Control)系统对冷带轧机成品带钢的厚度精度起着重要的作用。针对300可逆冷带轧机,进行了过程优化级计算机控制的研究,开发出了液压AGC系统的过程优化级计算机控制系统。液压AGC系统的过程优化级计算机控制,可以实现轧制规程的计算、过程控制级所需设定值的设定、轧制过程数据的采集以及人机界面的显示等功能。同时,进行了轧制试验。%Rolling process of the cold rolling mill is a complicated physical process, so the hydraulic AGC system is very important to the thickness precision of strips of cold rolling mill. In this paper, the computer control of process optimization level was researched, and the computer control system of process optimization level was developed, aiming at 300 reverse cold rolling mill. By the computer control of process optimization level of the hydraulic AGC, it can realize the calculation of rolling schedule, the set of setting value needed by the process control level, the data acquisition of rolling process and the display of human-computer interface. At the same time, the rolling experiment was carried out, and the experiment result implied that it could eliminate the thickness error of strips effectively, adopting the provided computer control's strategy of the process optimization level.

  10. CZKQ5263龙门式车铣钻磨加工中心结构设计和优化%Structure Design and Optimization for CZKQ5263 Gantry-typed Machining Center of Turning, Milling, Drilling and Grinding

    韩玉坤; 张运真; 张传生


    To process large plate covered parts, based on the structure of vertical lathe, a modular machine tool with a movable gantry and a traditional vertical lathe worktable was designed. In the case of a fixture, the turning, milling, grinding of cylindrical surface, end surface and ring groove and the drilling, reaming of holes on the large plate covered parts were completed, reducing clamping times, saving time of handling, lifting and clamping part. A three-dimensional model of the whole modular machine tool was built and the multi-body kinematic analysis was made. Aiming at the key component, finite element analysis was carried out to optimize its structure.%针对大型盘盖类零件的加工要求,参照立式车床的结构,设计一种由可动式龙门框架和传统立车工作台组合而成的机床.在一次装夹的情况下,能够完成大型盘盖类零件的外圆、端面和环槽的车、铣、磨以及钻、铰孔等工作,可减少装夹次数,节约搬运、吊装、装夹的时间.建立了整机的三维模型并进行了多体运动学分析,针对关键零件进行了有限元分析和仿真设计,改善了产品的结构.

  11. High-speed steel rolls used for cold rolling

    QU Haixia; WU Qiong; SUN Dale


    During cold rolled production of steel,each change of rolls causes a halt in production and affects the roll’s grinding maintenance and consumption.Consequently,rolls are very critical to the costs of steel production. Besides the rolling accidents,surface quality problems,including inhomogeneous wear and a decrease of the surface roughness of the rolls are other main reasons for outage and a change of the rolls.Therefore,safe rolls,with superior wear resistance and roughness retentivity will be a future trend in the cold rolling steel industry.In this study,the property characteristics and in-service performance of high-speed steel(HSS)cold rolling work rolls at Baosteel are discussed.The results of this study indicate that in-service performance of HSS cold work rolls has an improvement over conventional rolls.Implementation of HSS work rolls will prolong the rolling campaign and improve the rolling stability,thus,the cost of cold rolling production can be better controlled.

  12. 轧机辊系滞后非线性垂直振动系统的振动特性%Vibration Characteristics of Hysteretic Nonlinear Vertical Vibration System of Rolling Mill Roller

    刘浩然; 侯东晓; 时培明; 刘飞


    考虑轧件弹塑性变形的滞后非线性作用,建立一种轧机辊系滞后非线性垂直振动动力学模型.运用奇点稳定性理论分析该滞后非线性系统的稳定性,得到了系统出现各种不同奇点的条件.同时采用渐进法求解系统在主共振情况下的解析近似解,得到了系统的主共振幅频特性方程.最后以实际轧机参数为例,分析轧件的非线性刚度、阻尼等参数对轧机主共振幅频响应的影响,并研究轧机在不同外部扰动下的分岔行为,发现在不同的外部扰动下,轧机表现出周期、倍周期以及混沌等多种动力学行为,这为研究和抑制轧机振动问题提供了理论参考.%A kind of hysteretic nonlinear vertical vibration dynamic model is established which considers hysteresis of strip's plastic deformation. The stability of the hysteretic nonlinear system is analyzed by using stability theory of singularity, and the conditions for the emergence of various singular points are obtained. Then the analytical approximate solution of the system under periodic excitation is accounted, and the primary resonance amplitude-frequency equation of the system is obtained. Finally, according to the actual parameters of rolling mill, the influence of nonlinear stiffness and nonlinear damp of rolled piece on the primary resonance amplitude-frequency response of rolling mill is analyzed, and the bifurcation behaviors of rolling mill under different external disturbances are studied. It is found that the rolling mill exhibits many dynamic behaviors such as periodic, period-doubling motion and chaos. The results provide theoretical reference for researching and suppressing rolling mill vibration.

  13. Vertical Short Crack Initiation in Medium Carbon Bainitic Steel Under Mild Tractive Rolling Contact

    DOU Peng; SUO Shuang-fu; BAI Bing-zhe; YANG Zhi-gang; LI You-guo


    To improve the current grinding procedure of the back-up roll of CVC hot rolling mills so that the back-up roll service life can be extended, the crack initiation and propagation behavior of medium carbon bainitie back-up roll steel was investigated, a kind of asperity-scale, surface originated vertical short cracks occurred at 5 × 102 -1 × 104 cycles. Theoretical analysis indicated that the maximum tensile stress occurring at the back edge of the contact of as-perities keeps at above 1 347. 97 MPa, and ratcheting and cyclic plastic deformation take place at such sites within 1 × 104 cycles. The early initiation of the vertical short cracks is caused by the asperity contact. According to the crack initi-ation mechanism, short crack behavior and preventive grinding strategy, steel consumption can be reduced considera-bly by decreasing the surface roughness and removing the asperity influenced surface thin layer at about 70%-80% of the surface distress life.

  14. Effect of wet grinding on structural properties of ball clay

    Purohit, A.; Hameed, A.; Chander, S.; Nehra, S. P.; Singh, P.; Dhaka, M. S.


    In this paper, the effect of wet grinding on structural properties of ball clay is undertaken. The wet grinding treatment was performed employing ball and vibro mills for different time spells of 2, 4, 8 and 16 hours. The structural properties were carried out using X-ray diffraction (XRD). The structure of ground samples is found to be simple cubic. The crystallographic parameters are calculated and slight change in lattice constant, inter planner spacing and particle size is observed with grinding treatment. The results are in agreement with the available literature.

  15. Measurement of moisture in mill feed ore

    Timm, A.R.; Moench, P.; Moisel, E. (Council for Mineral Technology, Randburg (South Africa))


    The control of the moisture in the feed to a mill is very important for efficient mill operation. Water is added continuously to the ore fed to a mill to maintain a suitable mix of ore and moisture in the mill. However, problems arise because of the large variation in the moisture content of the ore, which affects the efficiency of the grind. If too little moisture is present, the mill is unable to grind the ore finely enough, creating instead a thick 'porridge' that causes the mill to choke up. On the other hand, too much moisture results in inefficient grinding because the ore is flushed through the mill too quickly. Several techniques are available for measuring moisture and Mintek undertook an investigation in an attempt to develop a reliable robust moisture meter suitable for monitoring the moisture content of ore, which include the following: neutron backscattering, infrared absorption, microwaves, capacitance and moisture as a function of conductivity.

  16. Assessment of air pollution and its effects on the health status of the workers in beam rolling mills factory (Iran National Steel Industrial Group from Ahvaz-Iran

    Rafiei Masoud


    Full Text Available Background: Air pollutants of iron- and steel-making operations have historically been an environmental and health hazard. These pollutants include gaseous substances such as sulfur oxide, nitrogen dioxide, and carbon monoxide. The Iran National Steel Industrial Group beam rolling mills factory has two production lines viz. line 630 and line 650, with different beam production capabilities and is capable of producing different types of beams. Materials and Methods: A retrospective cross-sectional study on 400 workers in different exposure levels to environmental pollution was performed during 2005 to determine the mean value of respirable particulate matter (RPM concentrations and its effects on the health status of workers. To elicit information regarding the health status of the worker, the National Institute for Occupational Safety and Health standard questionnaire was used. Fisher′s exact test was performed to assess the relative risk (RR of exposure to air pollution on cardiovascular diseases, chest tightness, cough, difficulty in retention, i.e. loss of memory, tension, occupational fatigue, and occupational stress in exposed workers. Results: There was significant difference in RPM pollution level between two product lines. The RR of exposure to air pollution on cardiovascular diseases, chest tightness, cough, difficulty in retention, i.e. loss of memory, tension, occupational fatigue, and occupational stress in exposed workers were 2.78, 2.44, 2.15, 1.92, 1.57, 3.90, and 2.09, respectively.

  17. Study on anaerobic treatment of hazardous steel-mill waste rolling oil (SmWRO) for multi-benefit disposal route.

    Ma, Huanhuan; Li, Zifu; Yin, Fubin; Kao, William; Yin, Yi; Bai, Xiaofeng


    Steel-mill waste rolling oil (SmWRO) is considered as hazardous substance with high treatment and disposal fees. Anaerobic process could not only transform the hazardous substance into activated sludge, but also generate valuable biogas. This study aimed at studying the biochemical methane potential of SmWRO under inoculum to substrate VS ratios (ISRs) of 0.25, 0.5, 1, 1.5, 2 and 3 using septic tank sludge as inoculum in mesophilic and thermophilic conditions, with blank tests for control. Specific biogas yield (mL/g VS(added)), net biogas yield (mL/g VS(removed)) and VS removal were analyzed. The ANOVA results indicated great influence of ISR and temperature on studied parameters. ISR of 1.5 at 55°C and ISR of 1.5 and 2 at 35°C were suggested with the highest specific biogas yield (262-265 and 303mL/g VS(added)). Kinetic analysis showed that Gompertz model fit the experimental data best with the least RMSE and largest R(2).

  18. Adsorption of single-strand alkylammonium salts on bentonite, surface properties of the modified clay and polymer nanocomposites formation by a two-roll mill

    Hoshino, Jumpei [Materials Science and Engineering Programme and Nanotec Center of Excellence at Mahidol University, Faculty of Science, Mahidol University, Rajathavee, Bangkok 10400 (Thailand); Limpanart, Sarintorn; Khunthon, Srichalai [Metallurgy and Materials Research Institute, Chulalongkorn University, Phayathai, Bangkok 10330 (Thailand); Osotchan, Tanakorn [Materials Science and Engineering Programme and Nanotec Center of Excellence at Mahidol University, Faculty of Science, Mahidol University, Rajathavee, Bangkok 10400 (Thailand); Physics Department, Faculty of Science, Mahidol University, Rajathavee, Bangkok 10400 (Thailand); Traiphol, Rakchart [Laboratory of Advanced Polymers and Nanomaterials, Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Naresuan University, Phitsanulok 65000 (Thailand); Srikhirin, Toemsak, E-mail: [Materials Science and Engineering Programme and Nanotec Center of Excellence at Mahidol University, Faculty of Science, Mahidol University, Rajathavee, Bangkok 10400 (Thailand); Physics Department, Faculty of Science, Mahidol University, Rajathavee, Bangkok 10400 (Thailand)


    The adsorption of tallow alkylammonium salts onto bentonite from the Lopburi province in Thailand, and the effect of surface wettability on the formation of polymer-clay nanocomposites are reported. We looked specifically at octadecyltrimethyl ammonium chloride (S18), a popular member of the tallow alkylammonium salt family. The adsorption of S18 onto the bentonite interlayer can be divided into three distinct stages depending upon the initial concentration of S18. These stages are (a) monolayer formation, (b) intermediate state of double layer formation and (c) double layer formation. A decrease in surface energy driven by drops in the values of the polar and dispersive components was observed as the amount of surfactant surface coverage increased. Using thermal gravimetric analysis (TGA), the critical surface energy (CSE) of organoclay was found to decrease as the amount of absorbed S18 increased. S18 organoclay with different degrees of surface coverage was used in a two-roll mill to prepare high-density polyetheylene (HDPE)-clay nanocomposites. The oxidized polyethylene wax (OWax) was used as a dispersing agent to promote the delamination of the organoclay platelets. The results from X-ray diffraction (XRD) and transmission electron microscope (TEM) indicated a difference in the dispersing capability of the organoclay.

  19. 1580热轧R2粗轧机主传动十字轴失效分析%Invalidation analysis for main driving cross axle of R2 roughing mill in 1580 hot rolling mill



    对宝钢1580热轧R2粗轧机主传动十字轴的失效原因进行了分析,指出该十字轴主要是在1.5倍额定负荷以上的工况条件下产生接触疲劳破坏,并提出了对十字轴表面重新加工处理,使其恢复表面硬度和粗糙度,重新单配轴承的修复方案,延长了十字轴的使用寿命.%The invalidation reason of R2 main driving cross axle in Baosteel 1580 hot rolling mill is analyzed.It is pointed out that the contact fatigue failure of the cross axle is due to more than 1.5 times of nominal load under working condition.An approach to treat the damaged working surface of the cross axle, and recover its surface stiffness and roughness, then make up bearing is put forward, and that service life of cross axle is prolonged.

  20. 3950mm宽厚板铝板轧机工作辊的热处理%Heat Treatment for Work Roll of 3 950 mm Aluminum Heavy Plate Mill

    陈太辉; 郭峰


    The forged steel Cr5 is used as the material of work rolls .3 950 mm aluminum heavy plate mills have been researched and developed successfully by adjusting quenching and tempering processes and designing installation auxiliary tools and applying differential temperature spray way , which is ensured to meet various technical requirements of work roll and provides new idea for manufacturing work roll .%采用Cr5锻钢工作辊材质,通过调整调质方式以及设计安装辅具,采用差温喷雾的方式成功制造出3950 mm宽厚板铝板轧机工作辊,较好地保证了工作辊的各项技术要求,为工作辊的制造提供了新思路。

  1. Integrated Modeling and Intelligent Control Methods of Grinding Process

    Jie-sheng Wang


    Full Text Available The grinding process is a typical complex nonlinear multivariable process with strongly coupling and large time delays. Based on the data-driven modeling theory, the integrated modeling and intelligent control method of grinding process is carried out in the paper, which includes the soft-sensor model of economic and technique indexes, the optimized set-point model utilizing case-based reasoning, and the self-tuning PID decoupling controller. For forecasting the key technology indicators (grinding granularity and mill discharge rate of grinding process, an adaptive soft-sensor modeling method based on wavelet neural network optimized by the improved shuffled frog leaping algorithm (ISFLA is proposed. Then, a set point optimization control strategy of grinding process based on case-based reasoning (CBR method is adopted to obtain the optimized velocity set-point of ore feed and pump water feed in the grinding process controlled loops. Finally, a self-tuning PID decoupling controller optimized is used to control the grinding process. Simulation results and industrial application experiments clearly show the feasibility and effectiveness of control methods and satisfy the real-time control requirements of the grinding process.

  2. PQF轧管机的摆臂焊接工艺研究与应用%Welding Process Research and Application for Swing Arm of PQF Rolling Mill

    王东; 张永明; 邢伏祥


    PQF轧管机的摆臂为厚板结构,材质Q345-D,质量达3.2 t,机加工面多、空间尺寸多、几何公差复杂,要求结构件组对焊接变形要控制到最小,一般焊接工艺无法保证焊接质量.本文探讨了采用整体组对,辅以拉撑刚性固定的优化焊接工艺,防止产生未焊透、裂纹等缺陷,选择多层多道对称交替施焊,有效地控制了焊接变形,且焊后进行去应力工艺,保证了机加工面合理的加工余量,满足了设计尺寸偏差及几何公差.%The swing arm of PQF rolling mill is the thick fabric with the materials Q345-D and weight 3 200 kg. There are many machine surfaces and complex geometric tolerance. The structure must have good fabricate quality and small welding distortion. It cannot ensure welding quality to commonly welding procedure. We have discussed that fitting whole and fix up rigidity with supports and optimize welding technic avoiding a few welding defects such as incomplete penetration et al. We have chosen effective means to control welding distortion that depends on multilayer symmetry welding by turns and carrying through heat treatment for release stress. All these assured logical excrescent machine measure, dimension warp and complex geometric tolerance.


    Yury Gutsalenko


    Full Text Available The paper generalizes on the one hand theory of kinematic-geometrical simulation of grinding processes by means of tools with working part as binding matrix with abrasive grains located in it in random manner, for example diamond grains, and on the other hand practical performance of combined grinding process, based on introduction of additional energy as electric discharges and called by the organization-developer (Kharkov Polytechnic Institute «diamond-spark grinding» as applied to processing by means of diamond wheel. Implementation of diamond-spark grinding technologies on the basis of developed generalized theoretical approach allows to use the tool with prescribed tool-life, moreover to make the most efficient use of it up to full exhausting of tool-life, determined by diamond-bearing thickness. Development is directed forward computer-aided manufacturing.

  4. Development of electric control system of the large cold pipe rolling mill%大型冷轧管机组的电气控制系统研制



    LG720 cold pipe rolling mill is the first large-scale cold pipe rolling mill in the world. The electric sys-tem applies PLC、variable frequency speed regulation (VFSR)、PROFIBUS-DP network、SIMOTION D and HMI technologies, which can realize the muti-motor VFSR drive, especially in large inertia load feed-in and rotation mechanism with high dynamic response, high precision positioning and synchronization control. This system fully meets the production requirements of the large-scale cold pipe rolling.%LG720冷轧管机组是世界最大规格冷轧管机组。为该机组研制的电气系统采用了PLC、变频调速、PROFIBUS-DP网络通讯、SIMOTION D、HMI等技术,实现了多机变频调速传动,对大惯量负载的送进和回转机构实现高动态响应、高精度定位和同步控制,满足了大型冷轧管机组的生产要求。

  5. Grinding Properties of Abandoned Concrete

    ZHENG Fang-yu; WANG Li-jiu; LI Qiang


    The grinding properties of abandoned concrete, which consists primarily of hardened cement, limestone aggregate and river sand, are studied. Theoretical models of grinding are used to explain the experimental observation. The results show that 1) The principle disintegration mechanism of hardened cement and river sand is volumetric grinding, although at later stages grinding of cement becomes difficult because of its flaked structure; 2) The limestone grinding process can be divided into two steps. First, volumetric grinding, with an obvious component of surface grinding, followed by primarily surface grinding as the micro-particle content increases; 3) Initially, the principle mechanism of grinding limestone and river sand is volumetric grinding, albeit less efficient grinding than if these components were ground separately, and; 4) After 10 to 20 min of grinding the grinding bottleneck phenomenon appears and after 20 min of grinding the content of micro-particles is large and surface grinding is the main mechanism while the particle size of the mixture is smaller than that of separately ground river sand and cement but bigger than that of separately ground limestone.

  6. Model Predictive Control for an Industrial SAG Mill


    identication. When applied to MIMO systems we call this controller a MIMO-ARX based MPC. We use an industrial Semi-Autogenous Grinding (SAG) mill to illustrate the performance of this controller. SAG mills are the primary units in a grinding chain and also the most power consuming units. Therefore, improved...... control of SAG mills has the potential to signicantly improve eciency and reduce the specic energy consumption for mineral processes. Grinding circuits involving SAG mills are multivariate processes. Commissioning of a control system based on a classical single-loop controllers with logic is time...

  7. FEM Analysis of Rolling Pressure Along Strip Width in Cold Rolling Process

    LIU Xiang-hua; SHI Xu; LI Shan-qing; XU Jian-yong; WANG Guo-dong


    Using 3-D elastic-plastic FEM, the cold strip rolling process in a 4-high mill was simulated. The elastic deformation of rolls, the plastic deformation of the strip, and the pressure between the work roll and the backup roll were taken into account. The distribution of rolling pressure along the strip width was obtained. Based on the simulation results, the peak value of rolling pressure and the location of the peak were analyzed under different rolling conditions. The effects of the roll bending force and the strip width on the distribution of rolling pressure along the width direction were determined.

  8. Photoacoustic study of nanocrystalline silicon produced by mechanical grinding

    Poffo, C.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Lima, J.C. de, E-mail: fsc1jcd@fisica.ufsc.b [Departamento de Fisica, Universidade Federal de Santa Catarina, Campus Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Souza, S.M.; Triches, D.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Grandi, T.A. [Departamento de Fisica, Universidade Federal de Santa Catarina, Campus Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Biasi, R.S. de [Secao de Engenharia Mecanica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil)


    Mechanical grinding (MG) was used to produce nanocrystalline silicon and its thermal and transport properties were investigated by photoacoustic absorption spectroscopy (PAS). The experimental results suggest that in as-milled nanocrystalline silicon for 10 h the heat transfer through the crystalline and interfacial components is similar, and after annealed at 470 {sup o}C the heat transfer is controlled by crystalline component.

  9. 南钢无锡金鑫轧钢厂设备基座搬迁精密工程测量方法%The Precision Engineering Survey Method of NanGang Wuxi Jinxin Rolling Mill's Equipment Base Relocation



    In this paper,NanGang Wuxi rolling mill equipment for the precision engineering measurement base,combined with measurement of the actual situation,with a focus on how to avoid and reduce the error of measurement of mechanical equipment for large-scale impact.%本文主要介绍了针对无锡轧钢厂设备基座的精密工程测量,并结合测量中的实际情况,重点提出如何避免和降低误差对大型机械设备测量的影响.

  10. Nitramine Drying & Fine Grinding Facility

    Federal Laboratory Consortium — The Nitramine Drying and Fine Grinding Facility provides TACOM-ARDEC with a state-of-the-art facility capable of drying and grinding high explosives (e.g., RDX and...

  11. Roll Eccentricity Control Using Identified Eccentricity of Top/Bottom Rolls by Roll Force

    Imanari, Hiroyuki; Koshinuma, Kazuyoshi

    Roll eccentricity is a periodic disturbance caused by a structure of back up rolls in rolling mills, and it affects product thickness accuracy. It cannot be measured directly by sensors, so it should be identified by measured thickness or measured roll force. When there is a large difference of diameters between top and bottom back up roll, the performance of roll eccentricity control using feedback signals of roll force or thickness has not been so good. Also it has been difficult for the control to be applied from the most head end because it is necessary to identify the roll eccentricity during rolling. A new roll eccentricity control has been developed to improve these disadvantages and to get better performance. The method identifies top and bottom roll eccentricity respectively from one signal of roll force and it can start the control from head end. In this paper the new control method is introduced and actual application results to a hot strip mill are shown.

  12. Development of database and searching system for tool grinding

    J.Y. Chen


    Full Text Available Purpose: For achieving the goal of saving time on the tool grinding and design, an efficient method of developing the data management and searching system for the standard cutting tools is proposed in this study.Design/methodology/approach: At first the tool grinding software with open architecture was employed to design and plan grinding processes for seven types of tools. According to the characteristics of tools (e.g. types, diameter, radius and so on, 4802 tool data were established in the relational database. Then, the SQL syntax was utilized to write the searching algorithms, and the human machine interfaces of the searching system for the tool database were developed by C++ Builder.Findings: For grinding a square end mill with two-flute, a half of time on the tool design and the change of production line for grinding other types of tools can be saved by means of our system. More specifically, the efficiency in terms of the approach and retract time was improved up to 40%, and an improvement of approximately 10.6% in the overall machining time can be achieved.Research limitations/implications: In fact, the used tool database in this study only includes some specific tools such as the square end mill. The step drill, taper tools, and special tools can also be taken into account in the database for future research.Practical implications: The most commercial tool grinding software is the modular-based design and use tool shapes to construct the CAM interface. Some limitations on the tool design are undesirable for customers. On the contrary, employing not only the grinding processes to construct the grinding path of tools but the searching system combined with the grinding software, it gives more flexible for one to design new tools.Originality/value: A novel tool database and searching system is presented for tool grinding. Using this system can save time and provide more convenience on designing tools and grinding. In other words, the

  13. 铝板带材冷轧机压力 AGC 仿真对比与实验分析%Simulating Comparison and Experimental Analysis of Pressure AGC on Cold Rolling Mill for Aluminum Plate Strip

    安俊静; 白磊; 赵春江; 郝琳璐; 石建辉


    The automatic gauge control(AGC) effect of the cold rolling mill for aluminum plate strip was studied in three modes of BISRA-AGC ,GM-AGC and DAGC .The mathematical models of the system were built ,and these pressure AGC were simulated by MATLAB/Simulink software .The simulation data and the experimental results show that DAGC control model could effectively improve the thickness control accuracy of cold rolling mill at the low cost .%采用BISRA-AGC , GM-AGC和DAGC三种压力AGC控制方式,研究铝板带材冷轧机的自动厚度控制效果。建立系统的数学模型,使用MATLAB/Simulink软件进行仿真模拟,通过对比三种压力AGC控制下系统的模拟数据及实验结果得出, DAGC模型控制系统能够以较低成本投入有效改善冷轧机厚度控制精度。

  14. Non-linear twist vibration of main transmission system of vertical rolling mill%立辊轧机主传动系统的扭振非线性分析

    孟令启; 吴浩亮; 王建勋; 雷明杰


    In order to analyze and use the theory of main transmission of vertical rolling mill, a four-degree of freedom non-linear dynamical model on main transmission of vertical roller mill was established according to the actual parameters of the main transmission of 4200 vertical rolling mill. The bifurcation diagram, phase diagram and Poincare sections graph were obtained by Matlab software. The stability of periodic motion and the process of chaotic motion by ways of period doubling bifurcation were analyzed. The simulation results show that the movement of system is instable and leads to vibration Chaos when the driving force frequency is near the natural frequency of vertical rolling mill. Therefore, it should be avoided in the actual production. With the change of angular frequency, the system will change from the cycle movement to quasi-periodic motion. After a number of times the cycle, bifurcation eventually leads to the formation of chaos.%为了掌握立辊轧机主传动系统的扭振理论并且加以控制和利用,根据4200立辊轧机主传动系统的实际参数,建立立辊轧机主传动系统的4自由度非线性扭振模型,采用Matlab软件, 得到分岔图、相图和庞加莱截面,通过仿真分析其周期运动的稳定性以及通过倍周期分岔进入混沌的过程.仿真结果表明,当激振力频率与系统固有频率相近时,角位移增大,系统不稳定,在实际生产中要避免激振力频率与系统固有频率相近的工况;随着角频率的变化,系统由周期运动、准周期运动,经过一系列倍周期分岔最终导致混沌产生.

  15. CLAD Algorithm of Rolling Force Ratio Load Distribution on Hot Strip Mill%热连轧机轧制力成比例负荷分配的CLAD算法

    李维刚; 刘相华


    An algorithm called change load ratio by adjusting draft(CLAD) was presented to achieve on-line optimal setting of roll force ratio draft scheduling of hot strip mill.The key point was to minimize the difference between current rolling force ratios and goal rolling force ratios by adjusting draft deviation of different finishing mills.According to the principle of rolling force ratio,non-linear equations were established.Combined with assumptions,the coefficient matrix was simplified to a diagonal matrix,and the iterative formula and convergence condition of the proposed new algorithm were derived by mathematical method.An empirical interpolation method was proposed to determine the initial value of draft scheduling and make the convergence speed of CLAD faster.Simulation experiments for typical rolled strips of BAOSTEEL showed that the new algorithm can be used in on-line pass schedule calculation with the advantages such as fast computing speed and excellent convergence performance.%为了实现热连轧精轧机组负荷分配的在线优化设定,提出一种轧制力成比例负荷分配的新算法CLAD算法(change load ratio by adjusting draft).其要点是通过调整压下量的偏差来使当前轧制力与目标轧制力的偏差最小化.根据轧制力成比例原则建立非线性方程组,结合假设条件,将系数矩阵简化为对角阵,经数学推导给出了新算法的迭代公式和收敛条件.提出一种经验插值法确定初始值,使得负荷分配迭代计算能快速收敛.对宝钢典型轧制案例的模拟计算验证了新算法具有计算速度快、收敛性好等优点,可用于在线计算.

  16. 轧机滚动轴承载荷特性优化及边界元法解析%Optimization and BEM analysis of loading characteristics of roller bearing in rolling mill

    李明; 吕照宇


    The wide-type roller bearing is widely used in rolling mill, but its short longevity and burning accidents appear frequently. It is difficult for the bearing to reach the design target due to the accidents. The loading characteristics of the roller bearings in Model 600 four-roller rolling miU are analyzed with BEM. In the static determination roll system, the function of bearing pedestal optimum design on prolonging the hie of the roller bearing is discussed. The conclusions given in this paper are valuable for study on prolonging roller bearing life.%宽系列滚动轴承在轧机上广泛使用,频繁出现短寿烧损问题,很难达到设计寿命.采用边界元法对某600四辊轧机滚动轴承三维载荷特性进行解析,分析了在静定性辊系中,轴承座优化设计对延长轴承使用寿命的有利影响,并进行了创新设计,取得的结论对延长轧机轴承寿命研究具有普遍意义.

  17. Effect of Grinding Techniques on Absorbing Characteristics of Short Iron Fibers


    Microwave-absorbing properties of iron fibers can be adjusted by their aspect ratio. This paper presents several modification techniques for grinding long iron fibers to a suitable aspect ratio. The grinding instruments include pulsator, jet mill and muller. The aspect ratio distribution, microstructure, electromagnetic parameter and refiectivity of the samples were analyzed and discussed in detail. The results show that the fractions of 5<aspect ratio<40 for the three methods are 69.03%, 81.11% and 80.2%, respectively, that is,suitable short iron fibers can be obtained by the jet mill and muller. Furthermore, the short iron fibers milled by jet mill and muller have better absorbing propterties than those obtained by the pulsator under the same condition. Therefore, their microwave absorption properties can be improved by regulating the electromagnetic parameters with grinding.

  18. Simulation of type selection for 6-high cold tandem mill based on shape control ability

    PENG Yan; LIU Hong-min; WANG Dong-cheng


    A theoretical method for selecting strip rolling mill type that considered shape control ability was established using the figure alteration range that was worked by the alteration track of vector expressing strip's cross section (crown) to express the shape control ability of rolling mill. With the mathematical models and simulation software that were developed by the authors' own models, four types of mills were aimed, including HCM (6-high middle rolls shift type HC (high crown) -mill), HCMW (6-high middle rolls and work rolls shift type HC-mill), UCM (6-high middle rolls shift type HC-mill with middle roll bender) and UCMW (6-high middle rolls and work rolls shift type HC-mill with middle roll bender), and the shape and crown control ability of every mill type was analyzed and compared. An appropriate arrangement mode of tandem mill was brought forward. The results show that UCMW mill is a perfect choice for controlling shape and crown, and the area of control characteristics curve of UCMW (or UCM) is twice than that of HCM, but UCM mill is also a good choice for its simple frame. In other word, the shape and crown controlling ability of UCMW mill is better than that of UCM mill, but the frame of UCM mill is simpler than that of UCMW mill. As for the final type of mill, should be synthetically decided by thinking over fund and equipment technology.

  19. High Performance Grinding and Advanced Cutting Tools

    Jackson, Mark J


    High Performance Grinding and Advanced Cutting Tools discusses the fundamentals and advances in high performance grinding processes, and provides a complete overview of newly-developing areas in the field. Topics covered are grinding tool formulation and structure, grinding wheel design and conditioning and applications using high performance grinding wheels. Also included are heat treatment strategies for grinding tools, using grinding tools for high speed applications, laser-based and diamond dressing techniques, high-efficiency deep grinding, VIPER grinding, and new grinding wheels.

  20. Computation of Rolling Stand Parameters by Genetic Algorithm

    František Ďurovský


    Full Text Available Mathematical model of rolling process is used at cold mill rolling on tandemmills in metallurgy. The model goal is to analyse rolling process according to process datameasured on the mill and get immeasurable variables necessary for rolling control andoptimal mill pre-set for next rolled coil. The values obtained by model are used asreferences for superimposed technology controllers (thickness, speed, tension, etc. as well.Considering wide steel strip assortment (different initial and final thickness, differenthardness, and fluctuation of tandem mill parameters (change of friction coefficient, workrolls abrasion, temperature fluctuation, etc. the exact analysis of tandem is complicated.The paper deals with an identification of friction coefficient on a single rolling mill standby a genetic algorithm. Mathematical description of tandem mill stand is based on themodified Bland-Ford model. Results are presented in graphical form.

  1. Large-scale Evaluation of Nickel Aluminide Rolls in a Heat-Treat Furnace at Bethelehem Steel's (Now ISG) Burns Harbor Plate Mill

    Mengel, J.


    At Bethlehem Steel Burns Harbor Plate Division (now ISG Burns Harbor Plate Inc.)'s annealing furnace, new nickel aluminide intermetallic alloy rolls provide greater high-temperature strength and wear resistance compared to the conventional H series cast austenitic alloys currently used in the industry. Oak Ridge National Laboratory and Bethlehem (ISG) partnered under a U.S. Department of Energy, Office of Industrial Technology's Emerging Technology Deployment Program to demonstrate and evaluate the nickel aluminide intermetallic alloy rolls as part of an updated energy efficient large commercial annealing furnace system. Many challenges were involved in this project, including developing welding procedures for joining nickel aluminide intermetallic alloys with H-series austenitic alloys, developing commercial cast roll manufacturing specifications, working with several commercial suppliers to produce a quantity of high quality, reproducible nickel aluminide rolls for a large steel industrial annealing furnace, installing and demonstrating the capability of the rolls in this furnace, performing processing trials to evaluate the benefits of new equipment and processes, and documenting the findings. Updated furnace equipment including twenty-five new automated furnace control dampers have been installed replacing older design, less effective units. These dampers, along with upgraded flame-safety control equipment and new AC motors and roll-speed control equipment, are providing improved furnace control and additional energy efficiency. Energy data shows up to a 34% energy reduction from baseline after the installation of upgraded furnace damper controls along with up to a 34% reduction in greenhouse gases, potential for an additional 3 to 6% energy reduction per campaign of light-up and shutdown, and a 46% energy reduction from baseline for limited trials of a combination of improved damper control and straight-through plate processing. The straight

  2. Grind hardening process

    Salonitis, Konstantinos


    This book presents the grind-hardening process and the main studies published since it was introduced in 1990s.  The modelling of the various aspects of the process, such as the process forces, temperature profile developed, hardness profiles, residual stresses etc. are described in detail. The book is of interest to the research community working with mathematical modeling and optimization of manufacturing processes.

  3. The effect of roll with passive segment on the planetary rolling process

    Qing-Ling Zeng


    Full Text Available In three-roll planetary rolling process, there is secondary torsion phenomenon that may lead to rolling instability. This article proposed a new idea to alleviate the secondary torsion phenomenon by dividing the secondary torsion segment out of the roll as an independent and passive one. To study the performance of the roll with passive segment, the three-dimensional finite element models of planetary rolling process using actual roll or new roll with passive segment involving elastic–plastic and thermal–mechanical coupling were established by the software ABAQUS/Explicit, and a series of analysis had been done successfully. The rolling temperature and rolling force of planetary mill were in good agreement with the measured results, which indicated that the finite element method would supply important reference merit for three-dimensional thermo-mechanical simulation of the three-roll planetary rolling process. Comparing the simulation results of the two models, the results indicated that the change in the roll structure had just a little influence on the metal deformation, temperature, and rolling force, but it lessened the secondary torsion deformation effectively and improved the outside roundness of the rolled tube slightly. The research provided a new idea for the roll design of three-roll planetary mill (PSW.

  4. 工作辊凸度对超宽六辊CVC轧机板形调控性能的影响%Influence of Initial Crown of Work Roll on Strip Shape Adjusting Performance of Ultra-Wide 6-h CVC Mill

    黄华贵; 史英钦; 任新意; 杜凤山


    Aiming at the 6-h CVC mill of a 2 230 mm cold continuous rolling mill in some domestic plant, the influences of initial crown of work roll on loaded roll gap profile and contact pressure distribution between rolls under the roll bend-ing and shifting were investigated with three-dimensional nonlinear finite element method. The numerical simulation re-sults show that when the work roll profile is parabolic type with initial crown of 0-75μm, the adjusting range of roll crown shifts but its area remains unchanged. And the peak value and unevenness of the contact pressure between rolls are a little improved with increasing the initial crown of work roll, which is beneficial for reducing the roll abrasion. In addition, the adjusting range of roll crown under different strip widths was investigated, and the results show that 6-h CVC has a higher performance in strip shape adjusting for width strip than for narrow strip. It also provides theoretical foundation for the rolling mill type selection in wide thin strip cold rolling.%以国内某2230 mm冷连轧机组六辊CVC轧机为研究对象,利用非线性有限元方法,模拟分析了弯辊和窜辊综合调控下工作辊初始凸度对承载辊缝形状、辊间接触压力分布的影响规律。结果表明,当工作辊采用凸度为0~75μm的抛物线辊型时,轧机承载辊缝凸度调控域发生平移而面积基本不变,但随着工作辊初始凸度增加,辊间接触压力峰值和不均匀度均有所改善,有利于降低轧辊磨损和辊耗。对比分析了不同板宽条件下的辊缝凸度调节域,结果表明,CVC轧机对宽带钢的板形调控能力要明显高于窄带钢,且对二次、四次板形具有较好的抑制作用,为宽薄带钢冷轧机型选择提供了理论依据。

  5. Three-Dimensional Model for Strip Hot Rolling

    ZHANG Guo-min; XIAO Hong; WANG Chun-hua


    A three-dimensional model for strip hot rolling was developed, in which the plastic deformation of strip, the thermal crown of rolls, roll deflection and flattening were calculated by rigid-plastic finite element method, finite difference method, influential function method and elastic finite element method respectively. The roll wear was taken into consideration. The model can provide detailed information such as rolling pressure distribution, contact pressure distribution between backup rolls and work rolls, deflection and flattening of work rolls, lateral distribution of strip thickness, and lateral distribution of front and back tensions. The finish rolling on a 1 450 mm hot strip mill was simulated.

  6. Modification of the Filter in the Turbid Circulating Water System at Meishan Steel Hot Rolling Mill and Operating results%梅钢热轧浊循环系统过滤器的改造及运行效果



    针对梅钢热轧浊循环系统过滤器出现的问题,进行了详细的分析,并制定了相关改进措施.认为过滤器本体设计、制造存在缺陷,对其改进后,运行稳定性得到了显著提高.%Problems in the high-speed sand filter of the turbid circulating cooling water system at Meishan Steel Hot Rolling Mill were analyzed in detail and corresponding im-provement measures were also drawn up. It was found that the design and manufacture of the filter body had defects and modification was carried out, which has significantly improved op-eration stability.


    Michał Rejdak


    Full Text Available The paper presents the results of coal milling tests in aspect of slurry fuel preparation. The tests were carried out with the use of vibrating mill with working chamber of 47.5 dm3. The influence of milling time, amount and composition of grinding aids on degree of fineness and particle size distribution has been investigated. It has been found that the efficiency of the grinding process (in this type of milling device depends primarily on the milling time and the share of grinding aids and - to a lesser extent - on their polydispersity. The study allows to conclude that the grinding time, composition and share of used grinding aids enable to control the final grain size of coal which has an impact on apparent viscosity of coal water slurry.


    V. A. Lutsenko


    Full Text Available Using of new arrangement of finishing train of block structure with divisibility of deformation and system of inter-block control of the semi-finished rolled products temperature enables to decrease disorder of mechanical properties, to reduce the depth of the decarbonized layer.

  9. Roll-to-Roll production of carbon nanotubes based supercapacitors

    Zhu, Jingyi; Childress, Anthony; Karakaya, Mehmet; Roberts, Mark; Arcilla-Velez, Margarita; Podila, Ramakrishna; Rao, Apparao


    Carbon nanomaterials provide an excellent platform for electrochemical double layer capacitors (EDLCs). However, current industrial methods for producing carbon nanotubes are expensive and thereby increase the costs of energy storage to more than 10 Wh/kg. In this regard, we developed a facile roll-to-roll production technology for scalable manufacturing of multi-walled carbon nanotubes (MWNTs) with variable density on run-of-the-mill kitchen Al foils. Our method produces MWNTs with diameter (heights) between 50-100 nm (10-100 μm), and a specific capacitance as high as ~ 100 F/g in non-aqueous electrolytes. In this talk, the fundamental challenges involved in EDLC-suitable MWNT growth, roll-to-roll production, and device manufacturing will be discussed along with electrochemical characteristics of roll-to-roll MWNTs. Research supported by NSF CMMI Grant1246800.


    田丰; 苏驭虎


    连轧主厂房为单层厂房,下柱为钢管混凝土双肢柱,上柱为焊接工字型柱,屋面大梁为焊接工字钢梁.基本柱距12m.设有80/20t吊车3台.厂房内设有7架精轧机及配套的设备基础,地下结构复杂,深迭8m.地面荷载为100kPa,屋面及墙面均采用保温压型钢板.同时,檩条节点做了技术改进.%The main building for the continuous rolling mill is aone-storied factory building. The bottom parts of the columns are steel-pipe concrete battened column. The top parts of the columns are welding Ⅰ-column. The roof beams are welding Ⅰ-steel beam. Columns space basically at 12m. Three cranes (each has a capacity of 80/20t) and 7 finishing mills with matching equipment foundations are equipped inside. There is a complexity in the sub-structure. The depth reaches as 8m. The ground loading is 100kPa. The corrugated sheet steel is used for the wall cladding system and the roof. Certain improvements have been made under the connection points of the purlins.

  11. [Radical formation by grinding of commercial tablets according to hospital and pharmacy prescription].

    Kuzuya, Masayuki; Kondo, Shin-ichi; Ishikawa, Takaaki; Furuta, Youji; Aramaki, Hideki; Sasai, Yasushi; Yamauchi, Yukinori


    We examined mechanoradical formation in the grinding process of commercial tablets using electron spin resonance (ESR). Mechanoradicals were detected in all tested samples (23 types of commercial tablets) when the ball-milling of tablets was conducted under anaerobic conditions and some were fairly stable even in air. Thus the grinding may cause changes in the physicochemical properties of ingredients included in commercial tablets. Because high quality is demanded in pharmaceuticals, these results suggest more caution should be taken in the grinding of commercial tablets in hospitals and pharmacies.

  12. Design of ADRC for Automatic Position Control Stopping System of Rolling Mill%轧机自动位置控制停车系统ADRC控制器设计

    张瑞成; 陈陆曦


    Based on analyzing the damping force ,the elastic force and the roll eccentricity force between the roll and the strip ,a non-linear model of the automatic position control (APC) stopping system of rolling mill is derived .The dynamic analysis shows the APC stopping system has the chaotic characteristics .Based on the characteristics of the APC stopping system ,such as nonlinear and varia-ble parameters ,a two-order active disturbance rejection controller (ADRC) for the automatic position control stopping system is de-signed ,and the simulation is done within uncertainty environment .The simulation results show that the controller has ideal robust-ness to the system chaos and the large load disturbance ,and rapid and smooth control process and high steady precise performances can be implemented .%在考虑轧辊与轧件间的阻尼力、弹性力和轧辊偏心力的基础上 ,建立了一个轧机自动位置控制(A PC ) 停车系统的非线性模型 ,对其动力学特性分析表明该系统具有混沌特性.针对此系统具有非线性、变参数的特点 ,采用自抗扰控制 (ADRC ) 方法设计二阶 ADRC控制器 ,并在不确定性环境下进行仿真研究.结果表明 :ADRC控制器对于系统出现的混沌和大负载干扰具有理想的鲁棒能力 ,其控制过程快速、平滑 ,稳态精度高.

  13. 线、棒材轧机主轧线物料跟踪功能分析%Material tracking for bar & high speed wire rolling mill

    李松辽; 刘洪敏; 郭贵云


    Based on the several bar and wire rolling production lines that Chongqing Iron and Steel Design-ing Institute has achieved, the principle and process of material tracking for bar & high speed wire rollingmill with signals from hot metal detector, loop scanner and loading metal in rolling gap are described. Thephantom billet function is also introduced briefly.%结合我院所做的几条线、棒材轧机生产线的情况,介绍线、棒材轧机主轧线通过热金属检测器、活套扫描器、咬钢信号等设备和信号进行物料跟踪控制功能的原理和过程以及模拟轧制功能。

  14. Online SAG Mill Pluse Measurement and Optimization

    Raj Rajamani; Jose Delgadillo; Vishal Duriseti


    The grinding efficiency of semi autogenous milling or ball milling depends on the tumbling motion of the total charge within the mill. Utilization of this tumbling motion for efficient breakage of particles depends on the conditions inside the mill. However, any kind of monitoring device to measure the conditions inside the mill shell during operation is virtually impossible due to the severe environment presented by the tumbling charge. An instrumented grinding ball, which is capable of surviving a few hours and transmitting the impacts it experiences, is proposed here. The spectrum of impacts collected over 100 revolutions of the mills presents the signature of the grinding environment inside mill. This signature could be effectively used to optimize the milling performance by investigating this signature's relation to mill product size, mill throughput, make-up ball size, mill speed, liner profile and ball addition rates. At the same time, it can also be used to design balls and liner systems that can survive longer in the mill. The technological advances made in electronics and communication makes this leap in instrumentation certainly viable. Hence, the instrumented grinding ball offers the ability to qualitatively observe and optimize the milling environment. An instrumented load cell package that can measure the force of impacts inside the grinding chamber of a mill is developed here. The signal from the instrumented load cell package is interpreted in terms of a histogram termed as an impact spectrum which is a plot of the number of impacts at a specific energy level against the energy. It reflects on the average force regime of the mill. The instrumented load cell package was calibrated against the ultra fast load cell which has been unanimously accepted as a standard to measure single breakage events. The load cell package was successfully used to produce impact spectra in an 8.5 inch lab scale mill. The mill speed and the ball size were varied to

  15. Unsteady-State Grinding Technology (II) Experimental Studies of Grinding Forces and Force Ratio


    As is known to all, grinding force is one of the most important parameters to evaluate the whole process of grinding. Generally, the grinding force is resolved to three component forces, namely, normal grinding force F n, tangential grinding force F t and a component force acting along the direction of longitudinal feed which is usually neglected because of insignificance. The normal grinding force F n has influence upon surface deformation and roughness of workpiece, while the tangential grinding force ...

  16. 酒钢选烧厂新型磨矿介质工业试验研究%In-situ Performance Evaluation for New-type Grinding Media in JISCO

    张志荣; 叶传勇; 司胜


    对酒钢选烧厂的磨矿介质进行了工业试验研究。结果表明,低铬铸球单耗为0.316 kg/t,高铬铸球单耗为0.214 kg/t,热轧钢球单耗为0.185 kg/t。采用热轧钢球作球磨机介质,碎球率极低,钢球经过一个阶段使用后,钢球硬度内外均匀,性能稳定,外形尺寸圆度好。%Commercial tests were carried out to evaluate the performance of grinding media used in Concentration and Sintering Plant of JISCO. The results show that, unit consumption of low⁃chrome cast iron ball, high⁃chrome cast iron ball and hot⁃rolled steel ball is 0.316, 0.214 and 0.185 kg/t, respectively. The hot⁃rolled steel ball, as grinding medium in ball mills, can have an extremely low breakage ratio, and remain stable performance after running for a certain period of time, with the uniform ball hardness for the inner and outer parts, roundness in boundary dimension remaining unchanged.

  17. Effects of grinding processes on enzymatic degradation of wheat straw.

    Silva, Gabriela Ghizzi D; Couturier, Marie; Berrin, Jean-Guy; Buléon, Alain; Rouau, Xavier


    The effectiveness of wheat straw fine to ultra-fine grindings at pilot scale was studied. The produced powders were characterised by their particle-size distribution (laser diffraction), crystallinity (WAXS) and enzymatic degradability (Trichoderma reesei enzymatic cocktail). A large range of wheat-straw powders was produced: from coarse (median particle size ∼800 μm) to fine particles (∼50 μm) using sieve-based grindings, then ultra-fine particles ∼20 μm by jet milling and ∼10 μm by ball milling. The wheat straw degradability was enhanced by the decrease of particle size until a limit: ∼100 μm, up to 36% total carbohydrate and 40% glucose hydrolysis yields. Ball milling samples overcame this limit up to 46% total carbohydrate and 72% glucose yields as a consequence of cellulose crystallinity reduction (from 22% to 13%). Ball milling appeared to be an effective pretreatment with similar glucose yield and superior carbohydrate yield compared to steam explosion pretreatment.

  18. The effects of lifter configurations and mill speeds on the mill power draw and performance

    Usman, Husni; Taylor, Patrick; Spiller, D. Erik


    Grinding mills used in the mining industries are the most energy-intensive operation and require a large number of wear resistant materials as well. The 1-m mill was used to investigate the effects of three lifter configurations, namely Hi (High), Rail and Hi-Lo (High-Low), and mill speeds on the mill performance. The MillTraj software was also utilized to simulate the outermost charge trajectories of the mill. At the given operating conditions, the power draw of Hi lifter was slightly lower than that of the Rail and the Hi-Lo and thus, the Hi lifter showed improvement in the mill efficiency. The product size distributions of the different lifters are very close and the size distribution of Hi-Lo lifter is slightly finer than those of the other lifters. At 74% critical speed, the size distributions of the Rail and Hi-Lo lifters were finer than at 70% critical speed, while that of Hi lifter otherwise occurs. At 80% critical speed, the size distributions of the lifters were coarser than at 74% critical speed. In this case, the outer charge trajectories of each lifter could go down on the mill shell rather than on the toe of the mill charge, resulting in ineffective grinding. Increasing face angles and/or mill charge would allow the mill to be operated at higher speeds.

  19. 宽带钢热连轧精轧机组成套辊形配置技术研究与应用%Research and Application of One Set Roll Contour Configuration Technology on Finishing Train of Hot Strip Mill

    王晓东; 李飞; 王秋娜; 李本海; 李彬


    为了实现热轧宽带钢板形的高精度控制,根据宽带钢热连轧精轧机组上游机架控制凸度与下游机架控制平坦度的特性,在首钢迁钢1580 mm热连轧生产线的精轧机组开发并应用了成套辊形配置技术.在F1机架工作辊采用负凸度辊形,加强带钢轧制过程的对中;在F2到F4机架工作辊应用低轴向力CVC辊形,对带钢进行凸度调控;在F5到F7机架工作辊上采用负凸度辊形,辅以长行程的工作辊周期性窜辊,均匀轧辊磨损,控制带钢的平坦度;在所有机架的支撑辊上采用VCR变接触式辊形,增加机架的横向刚度.采用此辊形配置后,带钢的板形控制精度达95%以上,同时,改善了带钢轧制稳定性,延长了轧制计划长度,实现了一定范围的自由规程轧制.%To realize the high precision control of hot rolled strip, in accordance with the characteristics of finishing train of hot strip mill: crown is controlled in the upper stream stands and flatness is realized in the down stream stands, one set roll contour configuration technology was developed and applied in 1580 mm hot strip mill of Qian' an Iron and Steel Company of Shougang Group. Negative crown contour was employed on work rolls of Fl stand to enhance the alignment during the rolling. CVC (Continuous Variable Crown) with lower thrust force was employed on work rolls from F2 to F4 to carry out the crown control function. Negative crown contour was adopted on work rolls of down stream stands F5 to F7 to control the flatness quality with a combination with the cyclic long stroke work roll shifting for the roll wear dispersing. VCR (Variable Crown Back-up Roll) contour was employed on all back-up rolls of the finishing mill to increase the cross rigidity of roll stack. After this roll contour configuration technology was utilized, strip shape control with a high accuracy of more than 95% and schedule-free rolling within a certain range have been realized, meanwhile

  20. Grinding analysis of Indian coal using response surface methodology

    Twinkle Singh; Aishwarya Awasthi; Pranjal Tripathi; Shina Gautam; Alok Gautam


    The present work discusses a systematic approach to model grinding parameters of coal in a ball mill.A three level Box-Behnken design combined with response surface methodology using second order model was applied to the experiments done according to the model requirement.Three parameters ball charge (numbers 10-20),coal content (100-200 g) and the grinding time (4-8 min) were chosen for the experiments as well as for the modeling work.Coal fineness is defined as the d80 (80 % passing size).A quadratic model was developed to show the effect of parameters and their interaction with fineness of the product.Three different sizes (4,1 and 0.65 mm) of Indian coal were used.The model equations for each fraction were developed and different sets of experiments were performed.The predicted values of the fineness of coal were in good agreement with the experimental results (R2 values of d80 varies between 0.97 and 0.99).Fine size of three different coal sizes were obtained with larger ball charge with less grinding time and less solid content.This work represents the efficient use of response surface methodology and the Box-Behnken design use for grinding of Indian coal.

  1. Dynamic Correction Algorithm of Rolling Force in Plate Rolling

    QIU Hong-lei; WANG Jun; HU Xian-lei; WANG Zhao-dong; WANG Guo-dong


    Based on the Shougang plat mill project, an on-line dynamic correction algorithm was analyzed. This algorithm can adjust model coefficients better because the reasonable correction is based on the measured and calculated rolling force. The results of application on site show that this on-line dynamic correction algorithm is effective.

  2. Influence of Hot Rolling Conditions on the Mechanical Properties of Hot Rolled TRIP Steel

    LI Zhuang; WU Di


    Influence of hot rolling conditions on the mechanical properties of hot rolled TRIP steel was investigated.Thermomechanical control processing(TMCP)was conducted by using a laboratory hot rolling mill,in which three different kinds of finish rolling temperatures were applied.The results show that polygonal ferrite,granular bainite and larger amount of stabilized retained anstenite can be obtained by controlled rolling processes.The finer ferrite grain size is produced through the deformation induced transformation during deformation rather than after deformation,which affects the mechanical properties of hot rolled TRIP steel.Mechanical properties increase with decreasing finish rolling temperature due to the stabilization of retained austenite.Ultimate tensile strength(UTS),total elongation(TEL)and the product of ultimate tensile strength and total elongation(UTS×TEL)reaches optimal values(791 MPa,36% and 28 476 MPa%,respectively)whenthe specimen was hot rolled for 50% reduction at finish rolling temperature of 700℃.

  3. Process engineering with planetary ball mills.

    Burmeister, Christine Friederike; Kwade, Arno


    Planetary ball mills are well known and used for particle size reduction on laboratory and pilot scales for decades while during the last few years the application of planetary ball mills has extended to mechanochemical approaches. Processes inside planetary ball mills are complex and strongly depend on the processed material and synthesis and, thus, the optimum milling conditions have to be assessed for each individual system. The present review focuses on the insight into several parameters like properties of grinding balls, the filling ratio or revolution speed. It gives examples of the aspects of grinding and illustrates some general guidelines to follow for modelling processes in planetary ball mills in terms of refinement, synthesis' yield and contamination from wear. The amount of energy transferred from the milling tools to the powder is significant and hardly measurable for processes in planetary ball mills. Thus numerical simulations based on a discrete-element-method are used to describe the energy transfer to give an adequate description of the process by correlation with experiments. The simulations illustrate the effect of the geometry of planetary ball mills on the energy entry. In addition the imaging of motion patterns inside a planetary ball mill from simulations and video recordings is shown.

  4. Effects of supercritical water and mechanochemical grinding treatments on physicochemical properties of chitin.

    Osada, Mitsumasa; Miura, Chika; Nakagawa, Yuko S; Kaihara, Mikio; Nikaido, Mitsuru; Totani, Kazuhide


    This study examined the effects of a combined pretreatment with supercritical water and mechanochemical grinding with a ball mill on the physicochemical properties of chitin and its enzymatic degradation. Following pretreatment with a combination of supercritical water and grinding, chitin had a lower mean molecular weight, a lower crystallinity index, a lower crystallite size, greater d-spacing, weaker hydrogen bonds, and the amide group was more exposed compared with untreated chitin. These properties increased the hydrophilicity of the chitin and enhanced its enzymatic degradation. The N,N'-diacetylchitobiose (GlcNAc)(2) yield after enzymatic degradation of chitin following pretreatment with supercritical water (400 °C, 1 min) and grinding (800 rpm, 10 min) was 93%, compared with 5% without any treatment, 37% with supercritical water pretreatment alone (400 °C, 1 min), and 60% with grinding alone (800 rpm, 30 min).

  5. 基于反馈BP网络的铝热连轧板凸度预报建模%Predictive Model of Aluminium Strip' s Crown at Hot Tandem Rolling Mill' s Finisher Delivery Based on BP Network



    “1+4”铝热连轧机是一个极其复杂的系统,为了精确地建模预报末机架出口处的板凸度,提出利用延时反馈BP网络对板凸度时间序列的预报方法来实现对铝带板凸度的精确建模预测.通过现场实验,采集大量试验数据,并通过数据分析,利用仿真验证该方法的有效性和优越性.%" 1 +4 " aluminum hot tandem rolling mill is a complicated system extremely. In order to predict crown of aluminum strip of the finisher delivery more accurately, this paper puts forward a method of time-lapse loop BP network to forecast the sequencing crown, and the reconfiguration of BP network is trained with LM algorithm. With a large number of test data gathered by on-the-spot experiment and analysis, simulation experiment indicates the predictive precision of relative crown(% ) of strip can reach 0.01% , effectivenes and superiority is proved.

  6. Application of PeakVue Technology on Diagnosing Faults of Bearings in Steel Pipe Rolling Mill%PeakVue 技术在诊断钢管轧机轴承故障上的应用

    田冶; 孙玉成; 毕辛; 崔通乐; 胡军; 于国江


    介绍了应用 PeakVue 技术诊断钢管轧机减速机轴承的工作状态。通过对 F2减速机轴承进行振动监测,以及对 PeakVue 峰值的研究,准确诊断出 F2减速机轴承的劣化及损坏程度,并依此制订出此轴承的寿命周期曲线。%The operating state of the reducer bearings of the steel pipe rolling mill diagnosed by the PeakVue technology is introduced. Based on the vibration monitoring for bearings of the F2 reducer and the study on the peak values of PeakVue, the damaged or degraded condition of the F2 reducer bearings is accurately diagnosed, and thus the life cycle curve of bearings is formulated based on the diagnosis.

  7. Efficient Fuel Pretreatment: Simultaneous Torrefaction and Grinding of Biomass

    Saleh, Suriyati Binti; Hansen, Brian Brun; Jensen, Peter Arendt


    Combining torrefaction and grinding of biomass in one reactor may be an attractive fuel pretreatment process. A combined laboratory torrefaction and ball mill reactor has been constructed for studies of the influence of temperature and residence time on the product yields and particle size......, and ash composition, where straw has a higher alkali content. This and other studies indicate that the large difference in the alkali contents of the biomasses is the main cause for the observed difference in torrefaction characteristics. Experiments with separate particle heating and grinding showed...... of straw for 90 min yielded a higher mass loss (27–60 wt %) and relative size reduction (59–95%) compared with spruce (mass loss of 10–56 wt % and size reduction of 20–60%). The two types of biomass investigated differ with respect to hemicellulose type, lignocellulosic composition, particle morphology...

  8. 板带轧机机电传动系统参激非线性扭振鲁棒控制研究%Study on robust control for parametric excitation nonlinear torsional vibration of a strip-rolling mill's mechanical and electrical drive system

    韩东颖; 时培明; 赵东伟


    While considering parametric excitation nonlinearity,uncertainty and load torque,the nonlinear torsional vibration dynamic model of a mechanical and electrical transmission system in a strip-rolling mill is built.The problem of the strip-rolling mill's motor-speed robust tracking and non-fragile control of the DC motor is studied.As the nonlinearity of the strip-rolling mill's mechanical and electrical drive system is translated into parameter uncertainty,the sufficient condition that lets the system attain quadratic stability and outside-disturbance attenuation is obtained using H∞theory,Lyapunov stability theory and the LMI method.In order to achieve the given speed-signal tracking and non-fragile control,a feedforward and compensatory controller is designed.The results of the real strip-rolling mill's simulation example verify the effectiveness of the proposed method,and the non-fragility of the controller is reflected as the controller's parameter robustness.This means that the effect of the torsional vibration non-fragile control of the strip-rolling mill's mechanical and electrical drive system can be fulfilled by choosing the parameters of the controller directly.%建立了含参激非线性、不确定性、负载转矩的轧机机电传动系统扭振动力学模型,研究了板带轧机电机速度鲁棒跟踪非脆弱控制问题。将板带轧机机电传动系统的非线性按参数不确定性处理,通过 H∞理论、Lyapunov 稳定性理论和线性矩阵不等式(LMI)方法得到了通过状态反馈使得系统满足二次稳定、抑制外界干扰的充分条件;为了实现给定速度信号跟踪非脆弱控制,设计了前馈补偿器。轧机实例仿真结果验证了方法的有效性,并发现控制器的非脆弱性表现为控制器参数的鲁棒性,即可以通过控制器参数的直接选取达到板带轧机机电传动系统扭振非脆弱控制效果。

  9. Vertical mill simulation applied to iron ores

    Douglas Batista Mazzinghy


    Full Text Available The application of vertical mills in regrind circuits is consolidated. This type of mill is now attracting interest in primary grinding applications, due to its higher efficiency when compared to ball mills, which are usually used at this stage. In this study, a coarse sample of iron ore was tested in a pilot scale grinding circuit with a vertical mill. Other three samples of pellet feed had already been tested with the methodology used in this study. The sample of coarse iron ore was characterized in laboratory tests carried out in a small batch ball mill. Selection and breakage function parameters were determined from the laboratory tests. The parameters were then used for simulating the pilot scale tests using Modsim™ software. The model previously implemented in Modsim™ has been successfully applied to represent the vertical mill operated with different ores. The simulations produced particle size distributions that were very close to the actual size distributions, and the predictions were accomplished only by imputing the calibrated parameters from the batch tests, the power draw and the feed size distribution of the pilot tests. The methodology is therefore useful for scale-up and simulation of vertical mills, only requiring laboratory tests that can be carried out in standard laboratory batch ball mills with small amounts of samples.

  10. Modulus Proposal for a Multi Axes Grinding of Sculptured Surfaces

    Jandečka, Karel


    This paper presents the use of the CAD/CAM system Cimatron for free programming of NC grinding machines. NC technology use, first of all in milling, turning and drilling operations, is widely dispersed at present. Development of these technologies depends to some extent on the cutting tools which are to be produced and sharpened to a high quality. Usable properties of the cutting tools, e.g. the shape accuracy, the quality of function surfaces, etc., are inspired by the production technology used. This technology plays a main role in production and sharpening of powerful and complex shaped cutting tools.

  11. Bruxism (Teeth Grinding or Clenching) (For Parents)

    ... Old Feeding Your 1- to 2-Year-Old Bruxism (Teeth Grinding or Clenching) KidsHealth > For Parents > Bruxism ( ... called bruxism , which is common in kids. About Bruxism Bruxism is the medical term for the grinding ...

  12. Rolling Stonesi kinokontsert kannab toorest rokiväge / Maris Meiessaar

    Meiessaar, Maris


    Martin Scorsese muusikalisest dokumentaalfilmist "Shine a Light - Valgus peale" (USA-Suurbritannia, 2008), mille keskmes on 2006. a. New Yorgi Beaconi teatris toimunud briti ansambli Rolling Stones kontsert

  13. Hybrid Hot Strip Rolling Force Prediction using a Bayesian Trained Artificial Neural Network and Analytical Models

    Abdelkrim Moussaoui; Yacine Selaimia; Hadj A. Abbassi


    The authors discuss the combination of an Artificial Neural Network (ANN) with analytical models to improve the performance of the prediction model of finishing rolling force in hot strip rolling mill process. The suggested model was implemented using Bayesian Evidence based training algorithm. It was found that the Bayesian Evidence based approach provided a superior and smoother fit to the real rolling mill data. Completely independent set of real rolling data were used to evaluate the capa...

  14. Plate Shape Control Theory and Experiment for 20-high Mill

    Zheng-wen YUAN; Hong XIAO


    Roll lfattening theory is an important part of plate shape control theories for 20-high mill. In order to improve the ac-curacy of roll lfattening calculation for 20-high mill, a new and more accurate roll lfattening model was proposed. In this model, the roll barrel was considered as a ifnite length semi-inifnite body. Based on the boundary integral equation method, the numerical solution of the ifnite length semi-inifnite body under the distributed force was obtained and an accurate roll lfattening model was established. Coupled with roll bending model and strip plastic deformation, a new and more accurate plate control model for 20-high mill was established. Moreover, the effects of the ifrst intermediate roll taper angle and taper length were analyzed. The ten-sion distribution calculated by analytical model was consistent with the experimental results.

  15. Causes Analysis of Spalling of Backup Roll Bearing and Its Countermeasures in 1220mm Cold Tandem Mill%1220mm轧机支撑辊轴承外圈裂纹剥落分析及对策

    段泉义; 徐俊; 程其华; 姚寿军


    To serious situation of backup roll bearing no-normal scrapped of 1220mm cold tandem mill of Baosteel, the causes were analyzed from lubrication and sealing. Therefore, some countermeasures were applied, including increasing oil level of lubrication oil tank from 30% to 70%~80%, shortening cycles of oil and water separation, changing cycles of seal replacement from 3~6 months to 3 months, strengthening bearing statue tracking and maintenance, and the number of support roller bearing scrapped due to the outer ring crack spalling was significantly reduced.%针对宝山钢铁股份有限公司冷轧薄板厂1220mm冷连轧机组支撑辊轴承非正常报废情况较为严重的问题,结合现场实际,从润滑、密封等多个角度分析了引起冷轧支撑辊轴承外圈裂纹剥落的深层原因,通过将润滑油油箱液位由30%增加到70%~80%,缩短润滑油的油水分离周期,将密封圈更换周期由原来的3~6个月改为固定的3个月,加强轴承状态跟踪及管理维护,使支撑辊轴承因外圈裂纹剥落而报废的数量明显降低.

  16. Unsteady-State Grinding Technology (I) Theoretical Generalization and Research on Grinding Mechanism


    In conventional grinding theory, it is obvious that there must be a very high hardness difference between grains of the grinding wheel and workpieces. The best grinding wheels are those giving the lowest "natural limiting surface roughness" while cutting at appreciable plunge velocities. With the development of new materials and new machining processes, conventional theories of grinding techniques are no longer suitable to explain many phenomena in the course of grinding procedures. In dealing with precisio...



    In the present paer, a thermal study was conducted for the grinding of granite with diamond tools. Three types of grinding-straight surface grinding, deep grinding(circular sawing), and vertical spindle grinding-were studied. Some surface grinding tests were also conducted using a CBN(cubic boron nitride) wheel. Temperature distributions on the workpiece surface were measured using a foil thermocouple and the energy partition to the workpiece was estimated using a temperature matching method. The temperature for CBN surface grinding was found to be much higher than for diamond grinding. Energy partitions to the granite were 30%~36% for CBN surface grinding, 25%~32% for diamond surface grinding, about 53% for vertical spindle grinding, and 5.5%~9% for diamond deep grinding. The low energy partition value in deep grinding also suggested that more of the heat generated by grinding in this case can be conducted to the grinding tool and promote tool wear.

  18. Ultrasonic precision optical grinding technology

    Cahill, Michael J.; Bechtold, Michael J.; Fess, Edward; Wolfs, Frank L.; Bechtold, Rob


    As optical geometries become more precise and complex and a wider range of materials are used, the processes used for manufacturing become more critical. As the preparatory stage for polishing, this is especially true for grinding. Slow processing speeds, accelerated tool wear, and poor surface quality are often detriments in manufacturing glass and hard ceramics. The quality of the ground surface greatly influences the polishing process and the resulting finished product. Through extensive research and development, OptiPro Systems has introduced an ultrasonic assisted grinding technology, OptiSonic, which has numerous advantages over traditional grinding processes. OptiSonic utilizes a custom tool holder designed to produce oscillations in line with the rotating spindle. A newly developed software package called IntelliSonic is integral to this platform. IntelliSonic automatically characterizes the tool and continuously optimizes the output frequency for optimal cutting while in contact with the part. This helps maintain a highly consistent process under changing load conditions for a more accurate surface. Utilizing a wide variety of instruments, test have proven to show a reduction in tool wear and increase in surface quality while allowing processing speeds to be increased. OptiSonic has proven to be an enabling technology to overcome the difficulties seen in grinding of glass and hard optical ceramics. OptiSonic has demonstrated numerous advantages over the standard CNC grinding process. Advantages are evident in reduced tool wear, better surface quality, and reduced cycle times due to increased feed rates. These benefits can be seen over numerous applications within the precision optics industry.

  19. Force Characteristics in Continuous Path Controlled Crankpin Grinding

    ZHANG Manchao; YAO Zhenqiang


    Recent research on the grinding force involved in cylindrical plunge grinding has focused mainly on steady-state conditions. Unlike in conventional external cylindrical plunge grinding, the conditions between the grinding wheel and the crankpin change periodically in path controlled grinding because of the eccentricity of the crankpin and the constant rotational speed of the crankshaft. The objective of this study is to investigate the effects of various grinding conditions on the characteristics of the grinding force during continuous path controlled grinding. Path controlled plunge grinding is conducted at a constant rotational speed using a cubic boron nitride (CBN) wheel. The grinding force is determined by measuring the torque. The experimental results show that the force and torque vary sinusoidally during dry grinding and load grinding. The variations in the results reveal that the resultant grinding force and torque decrease with higher grinding speeds and increase with higher peripheral speeds of the pin and higher grinding depths. In path controlled grinding, unlike in conventional external cylindrical plunge grinding, the axial grinding force cannot be disregarded. The speeds and speed ratios of the workpiece and wheel are also analyzed, and the analysis results show that up-grinding and down-grinding occur during the grinding process. This paper proposes a method for describing the force behavior under varied process conditions during continuous path controlled grinding, which provides a beneficial reference for describing the material removal mechanism and for optimizing continuous controlled crankpin grinding.

  20. The effects of pf grind quality on coal burnout in a 1 MW combustion test facility

    Richelieu Barranco; Michael Colechin; Michael Cloke; Will Gibb; Edward Lester [University of Nottingham, Nottingham (United Kingdom). School of Chemical, Environmental and Mining Engineering, Nottingham Fuel and Energy Centre


    A study was carried out to determine the effect of pf particle size distribution on coal burnout propensity in a 1 MW pulverised fuel burner. The specific aim of the work was to assess the improvement in combustion performance achievable by retrofitting commercially available high performance static or dynamic classifiers to existing plants. Two coals were used and were selected as representative of extremes in fuel characteristics experienced by coal importing utilities in Europe. Each coal was fired in the unit at a range of grind sizes to determine the overall impact of a variable performance from a mill. The levels of unburnt carbon in the resultant flyashes for the two coals showed significantly different behaviour. For the higher volatile coal, the unburnt carbon was found to be insensitive to grind quality. However, the coarser grinds of the other coal produced significantly lower unburnt carbon than expected when compared with the finest grinds. Generally the results indicate that the installation of improved classification technology, leading to a finer product, will help to lower unburnt carbon levels. Nevertheless, further work will be necessary to establish the levels of diminishing returns for grind size, burnout performance and grind costs. 21 refs., 4 figs., 4 tabs.

  1. Surface grinding of intermetallic titanium aluminides

    Gröning, Holger Andreas


    A deductive kinematic model of creep-feed and speed-stroke grinding processes is developed to identify possibilities to reduce the energy introduced into the workpiece. By computer tomography analysis and tactile measurements of the grinding wheel the pore volume and the static cutting edge number are determined and included in the model. Based on the kinematic model and the grinding wheel characteristics an analytical evaluation of the specific grinding energy for speed-stroke and creep-feed grinding is carried out. The deducted process design is evaluated in experimental investigations. The


    S. M. Zhuchkov


    Full Text Available The computer means allowing to ca n y out of analytical research of process continuous rolling on mills with the various technological circuits of manufacture is created. With the help of the developed information-analytical system continuous rolling, the urgent tasks of manufacture of hire on rolling mills, in particular, decrease of consumption of power resources can be successfully decided during continuous rolling at the expense of optimization existing or development of the new technological circuits of manufacture of hire.

  3. Affecting mechanism of grinding aid during ultrafine grinding%超细粉碎过程助磨剂的作用机理

    杨华明; 邱冠周


    通过粉体ζ-电位、矿浆粘度测定及光电子能谱(XPS)和分散率分析,研究了搅拌磨超细粉碎滑石粉过程中助磨剂的助磨行为.分析了六偏磷酸钠与滑石粉的表面作用及吸附特性,提出了助磨剂在超细粉碎过程中的吸附模型.此外,探讨了助磨剂对超细粉碎行为的影响.研究结果表明,助磨剂通过与滑石粉的吸附作用,降低了矿浆粘度,从而提高了超细粉碎的效率.%The aiding behavior of hexametaphosphate(hexa) during uhrafine grinding of talc with stirred mill is studiedthrough analysis of ζ-potenfial,pulp viscosity,XPS and scattering rate in the paper. The surfacial effect and adsorptioncharacteristics of Hexa on talc particles are analysed. A typical model of grinding aid during ultrafine grinding is given.Effect of Hexa on ultrafine grinding behavior is also discussed. The results show that it is the adsorption of Hexa and re-ducing pulp viscosity that improve the grinding efficiency.

  4. Research on the Friction between Mandrel and Workpiece during Tube Continuous Rolling by Full Floating Mandrel Mill%全浮动芯棒钢管连轧过程芯棒与轧件的摩擦研究

    齐秀美; 赵志毅; 苏惠超; 任学平


    应用有限元分析研究了8机架全浮动芯棒钢管连轧过程芯棒与轧件间的摩擦作用,揭示了该摩擦作用在轧制过程中的演变规律及其对连轧运动状态与电机能量分配的影响.结果表明,在第1-4机架的咬入过程中,毛管所受芯棒的摩擦作用从完全为负摩擦演变为正负摩擦共存,中性面随咬入的进行逐渐向接触区出口侧移动,且在第1机架中性面会完全移出接触区.在第5-8机架的咬入过程中,芯棒始终滞后于毛管,因而芯棒对毛管的摩擦作用均为负.稳定轧制阶段,芯棒在轴向受到的摩擦合力为零,其速度不发生变化.该阶段8个机架可以分为3类:其中1、2机架为滞后机架,第3机架为同步机架,4-8机架为导前机架.整个机组芯棒与毛管运动的中性面位于第3机架接触区,但在第2机架和第4机架接触区也存在芯棒与毛管速度相等的位置.芯棒在各机架的摩擦状态不同使其成为导前机架向滞后机架传递能量的工具.因此,第5-6机架在轧制能耗较低的情况下,电机仍保持较高的输出功率,而1、2机架的轧制能耗虽然较大,电机输出功率反而较小.%The friction between mandrel and workpiece was investigated with coupled thermo-mechanical finite element analysis during tube continuous rolling by eight-stand full floating mandrel mill. The friction evolution and its influences on rolling movement state and motor energy distribution were revealed. The results showed that when the tube was entering 1st-4th stands, the friction of the tube from the mandrel changed from entirely negative friction to the coexistence of negative and positive friction. The neutral plane moved towards the exit of the contact area gradually with the entering progressing, and it could move out the contact area at the 1st stand. When the tube was entering 5th-8th stands,the frictional force of the tube from mandrel was negative all the time as the mandrel always lags

  5. Influence of suspension stability on wet grinding for production of mineral nanoparticles

    S. Sakthivel; Venkatesan V. Krishnan; Pitchumani


    Grinding behavior of nanoparticles in an attritor mill and the minimum achievable particle size are strongly influenced by the suspension stability. In the present work, suspension stability (i.e. (-potential) of nanoparticles was studied by measuring pH as a function of grinding time in the wet milling process. It was found that after a certain time in an attritor mill, there is no further size reduction and the average product particle size increases monotonically. One of the reasons is that the production of submicron particles leads to more particle-particle interactions and consequently pH of the suspension decreases with grinding time. Usually pH value is related to suspension stability and it can be enhanced by addition of NaOH solution. The maximum negative (-potential of -51.2 mV was obtained at pH of 12 for silica. The higher the (-potential with the same polarity, higher will be the electrostatic repulsion between the particles. Hence, the maximum electrostatic repulsion force was maintained by the adjustment of pH value in wet milling. The experiments were conducted at different pH conditions which were maintained constant throughout the experiments and nanosized particles were obtained consequently.

  6. 基于谐波干扰的轧机主传动机电耦合系统参激振动机理研究%Study on parametrically excited vibration in the rolling mill electromechanical coupling system based on harmonic disturbance

    张瑞成; 王佩佩


    在考虑轧机电气系统谐波转矩及机械摩擦因数的基础上,建立直流电动机-轧机主传动机电耦合系统的模型。采用多尺度法求解该机电耦合模型在主参数共振情况下的一阶近似解,给出了振子的频率响应方程,用数值方法研究了定常解的稳定性,并应用Poincare映射方法和最大Lyapunov指数分析了谐波角频率对轧机主传动机电耦合系统非线性参激共振的影响。%The electromechanical coupling model of a rolling mill and DC motor system is established based on the mechanical friction factor and the harmonic torque of the rolling mill electrical system .By means of a multiple-scales method,the existence and stability of periodic solutions in a first order approximation close to the main parametric resonance are investigated ,and the frequency-response equation is provided .Bifurcations of the system and regions of chaotic solutions are found .And the impacts of the harmonic angular frequency on the rolling mill electromechanical coupling nonlinear parametric excitation resonance are ana -lyzed by the Poincare mapping method and the maximum Lyapunov exponent .

  7. Analysis of Grinding Force and Elastic Deformation in Thread Grinding Process

    Wei Wang


    Full Text Available Considering the grinding geometry of the thread grinding dynamic contact arc length, a dynamic numerical thread grinding model has been set up on the basis of study of a single grit grinding model. The properties of grinding force and dynamic contact arc-length have been studied by means of the developed numerical model. The results have shown that the angle of helix has little effect on the dynamic contact arc-length than the wheel speed on the dynamic contact arc-length. And the wheel speed also produced a large effect on grinding force.

  8. Thermal Behaviors of Work Roll in Finishing Trains of Hot Rolling


    In order to analyze the thermal field and thermal contour of work roll in finishing trains of hot rolling in rolling process, a quasi two-dimension implicit finite difference model is developed. To improve the calculating speed and precision, some special solutions are introduced, including the development of this model, the simplification of boundary conditions and the computation of heat transfer coefficients. The results show that these solutions of thermal behaviors of work roll are very much efficient and the model can be used as an on-line profile and flatness control model of large industrial mills.

  9. Polymorphic coupling vibration of a mill main drive system induced by synergy effect of motor current harmonics and rolling force ones%电流谐波与轧制力谐波协同诱发主传动多态耦合振动研究

    张义方; 闫晓强; 凌启辉


    现代大型热连轧机是一种复杂机电系统,轧机振动问题是影响轧机生产稳定的严重问题。利用扭矩遥测系统测试轧机机械传动系统扭振发现轧机主传动扭振波形及频谱中存在典型的强或弱两种振动特征。同时发现轧机在轧制过程中电机电流和轧制力存在谐波,当谐波与传动系统固有频率接近时将诱发较大的振动。为研究其机理,利用仿真技术求解了轧机主传动扭振与电流谐波和轧制力谐波激励的相关性。研究表明:随着谐波激励特征的变化,主传动扭振呈现多态强弱变化,从而为抑制轧机耦合振动提供理论依据。%Large modern hot strip mill is a complex electromechanical system.Vibration of a rolling mill is a serious problem affecting the stability of production.By using a torque telemetry system to measure the torsional vibration of the main mechanical drive system,it was shown that two typical characteristics of strong or weak vibration exist in the waveform and spectrum of the torsional vibration;meanwhile,there are harmonics of motor current and rolling force during the rolling mill’s production;when the harmonic frequencies are close to the natural frequencies of the main drive system, heavier torsional vibrations are induced in the mill main drive system.For the study of their mechanism,using computer simulation,the correlation between the main drive system torsional vibration and the harmonic excitations of motor current and rolling force was solved.The study results showed that with the changes in harmonics excitations,the torsional vibration of the main drive system reveals a polymorphic strong or weak variation.The results provided a theoretical foundation for suppressing rolling mills’coupling vibration.

  10. 29 CFR 1910.216 - Mills and calenders in the rubber and plastics industries.


    ... in accordance with this section and Subpart S of this part. (4) Mill roll heights. All new mill...) Mill safety controls—(1) Safety trip control. A safety trip control shall be provided in front and in back of each mill. It shall be accessible and shall operate readily on contact. The safety trip...

  11. Using of fluidized-bed jet mill to a super fine comminution of steel composite

    D. Urbaniak


    Full Text Available In many industries the demand for very fine material increases. In the metallurgical industry, for example, there is increasing use of the production of high density metal elements with the use of metallurgical powder composites. The use of powder composites requires prior their grinding. Unfortunately, the very fine grinding is not an easy process. The using for this purpose fluidized-bed jet mill was proposed in the paper. The attempts of grinding of metallurgical powder were carried out in the fluidized-bed jet mill. After the experiment analyses of particle size distribution of grinding products were performed. The results are presented in graphs. Analyses of the obtained results concluded that the grinding of very fine metallurgical composite is possible and produces positive results.

  12. Study on corrosive grinding of gears


    Careful grinding or honing is usually required in machining of gears in order to improvethe machining quality of gear surface. Thus several grinding additives were used to formulate syn-thetic grinding lubricants similar to superior running-in lubricants. Experimental results show thatthe tooth surface of the produced oblique gear and steel worm becomes extremely smooth aftergrinding at a certain load for about a half to one hour. Especially, the gear surface finished withspecially formulated grinding lubricant reaches mirror-like smoothness. The quality of the geartooth can be improved by corrosive grinding, while the corrosive grinding time can be controlled byadjusting the quantity of the corrosive additives and the speed and load of the gears.

  13. Specific grinding energy and surface roughness of nanoparticle jet minimum quantity lubrication in grinding

    Zhang Dongkun


    Full Text Available Nanoparticles with the anti-wear and friction reducing features were applied as cooling lubricant in the grinding fluid. Dry grinding, flood grinding, minimal quantity of lubrication (MQL, and nanoparticle jet MQL were used in the grinding experiments. The specific grinding energy of dry grinding, flood grinding and MQL were 84, 29.8, 45.5 J/mm3, respectively. The specific grinding energy significantly decreased to 32.7 J/mm3 in nanoparticle MQL. Compared with dry grinding, the surface roughness values of flood grinding, MQL, and nanoparticle jet MQL were significantly reduced with the surface topography profile values reduced by 11%, 2.5%, and 10%, respectively, and the ten point height of microcosmic unflatness values reduced by 1.5%, 0.5%, and 1.3%, respectively. These results verified the satisfactory lubrication effects of nanoparticle MQL. MoS2, carbon nanotube (CNT, and ZrO2 nanoparticles were also added in the grinding fluid of nanoparticle jet MQL to analyze their grinding surface lubrication effects. The specific grinding energy of MoS2 nanoparticle was only 32.7 J/mm3, which was 8.22% and 10.39% lower than those of the other two nanoparticles. Moreover, the surface roughness of workpiece was also smaller with MoS2 nanoparticle, which indicated its remarkable lubrication effects. Furthermore, the role of MoS2 particles in the grinding surface lubrication at different nanoparticle volume concentrations was analyzed. MoS2 volume concentrations of 1%, 2%, and 3% were used. Experimental results revealed that the specific grinding energy and the workpiece surface roughness initially increased and then decreased as MoS2 nanoparticle volume concentration increased. Satisfactory grinding surface lubrication effects were obtained with 2% MoS2 nanoparticle volume concentration.

  14. Study on the Friction Coefficient in Grinding


    The friction between the abrasive grains and workpi ec e is a crutial factor determining the main grinding output. Few studies have bee n carried out investigating the values of the friction coefficient in grinding, due to the difficulty of direct measurement. In this paper, a mathematical model of the friction coefficient in grinding has been established with the aid of a new grinding parameter C ge, which has close relations to wheel wear rate Z s, metal removal rate Z w, specific energy u and gr...

  15. Changeing of fly ash leachability after grinding

    Lakatos, J.; Szabo, R.; Racz, A.; Banhidi, O.; Mucsi, G.


    Effect of grinding on the reactivity of fly ash used for geopolymer production was tested. Extraction technique using different alkaline and acidic solutions were used for detect the change of the solubility of elements due to the physical and mechano-chemical transformation of minerals in function of grinding time. Both the extraction with alkaline and acidic solution have detected improvement in solubility in function of grinding time. The enhancement in alkaline solution was approx. 100% in case of Si and Al. The acidic medium able to dissolve the fly ash higher manner than the alkaline, therefore the effect of grinding was found less pronounced.

  16. Vertical Vibration of Moving Strip in Rolling Process Based on Beam Theory

    SUN Jianliang; PENG Yan; LIU Hongmin; JIANG Guangbiao; JIANG Guangbiao


    The shape and thickness qualities of strip are influenced by the vibration of rolling mill. At present, the researches on the vibration of rolling mill are mainly the vertical vibration and torsional vibration of single stand mill, the study on the vibration of tandem rolling mill is rare. For the vibration of tandem rolling mill, the key problem is the vibration of the moving strip between stands. In this paper, considering the dynamic of moving strip and rolling theory, the vertical vibration of moving strip in the rolling process was proposed. Take the moving strip between the two mills of tandem rolling mill in the rolling process as subject investigated, according to the theory of moving beam, the vertical vibration model of moving strip in the rolling process was established. The partial differential equation was discretized by Galerkin truncation method. The natural frequency and stability of the moving strip were investigated and the numerical simulation in time domain was made. Simulation results show that, the natural frequency was strongly influenced by the rolling velocity and tension. With increasing of the rolling velocity, the first three natural frequencies decrease, the fourth natural frequency increases;with increasing of the unit tension, when the rolling velocity is high and low, respectively, the low order dimensionless natural frequency gradually decreases and increases, respectively. According to the stability of moving strip, the critical speed was determined, and the matching relationship of the tension and rolling velocity was also determined. This model can be used to study the stability of moving strip, improve the quality of strip and develop new rolling technology from the aspect of dynamics.

  17. FEA-based optimization design for the safety pin of main shaft coupling in the main driving system of rolling mill%轧机主传动系统主联轴器安全销有限元优化设计

    田野; 李友荣; 王涛


    以某厂轧机主传动系统主联轴器安全销为研究对象,采用有限元的函数加载方式对其进行应力分析,对安全销的实际剪切强度进行校核,并在有限元软件中通过参数化建模对安全销退刀槽尺寸进行优化。仿真分析结果表明,优化后的安全销可以保证轧机主传动系统扭矩超过设定值时安全销及时断裂,对主传动系统起到保护作用。%With the safety pin of main shaft coupling in the main drive system of a rolling mill as the re-search obj ect,the stress distribution of the safety pin is calculated and the actual shear strength of the safety pin is checked by the function loading from the finite element analysis (FEA)method.The structural parameters of the safety pin are optimized by means of parametric modeling in the FEA software.Simulation results show that the shear fracture of the safety pin will surely occur when the system torque exceeds the preset value,thus protecting the main drive system of the rolling mill.

  18. Improved coal grinding and fuel flow control in thermal power plants

    Niemczyk, Piotr; Bendtsen, Jan Dimon


    A novel controller for coal circulation and pulverized coal flow in a coal mill is proposed. The design is based on optimal control theory for bilinear systems with additional integral action. The states are estimated from the grinding power consumption and the amount of coal accumulated...... in the mill by employing a special variant of a Luenberger observer. The controller uses the rotating classifier to improve the dynamical performance of the overall system. The proposed controller is compared with a PID-type controller with available pulverized coal flow measurements under nominal conditions...

  19. Research of cold-rolling oil for stainless sheet steel


    The research & application of cold rolling oil for stainless sheet steel are introduced inthis paper. The results indicate that this oil has well properties of anti-wear, oxidation, emulsifyingand fine rust-preventing characteristics, it can meet the employable demands of SENDZIMIR highspeed rolling mill at all.

  20. En route to a multi-model scheme for clinker comminution with chemical grinding aids

    Mishra, R K; Carmona, H A; Wittel, F K; Sawley, M L; Weibel, M; Gallucci, E; Herrmann, H J; Heinz, H; Flatt, R J


    We present a multi-model simulation approach, targeted at understanding the behavior of comminution and the effect of grinding aids (GAs) in industrial cement mills. On the atomistic scale we use Molecular Dynamics (MD) simulations with validated force field models to quantify elastic and structural properties, cleavage energies as well as the organic interactions with mineral surfaces. Simulations based on the Discrete Element Method (DEM) are used to integrate the information gained from MD simulations into the clinker particle behavior at larger scales. Computed impact energy distributions from DEM mill simulations can serve as a link between large-scale industrial and laboratory sized mills. They also provide the required input for particle impact fragmentation models. Such a multi-scale, multi-model methodology paves the way for a structured approach to the design of chemical additives aimed at improving mill performance.

  1. 金属矿磨矿设备研究与应用新进展%The Research in the Research & Application of Metal Mine Grinding Equipment



    阐述了近年来国内外金属矿山磨矿设备的研究和应用进展,涉及自磨(半自磨)机、球磨机和搅拌磨机等,主要综述了磨矿设备在大型化方面的研究与发展,介绍了国内外典型的应用情况。%This article elaborates the progress in the application and research of metal mine grinding equipment at home and abroad in recent years. The involved equipments are (semi) autogeneous mill, ball mill, agitating mill, vertical mill and Isa mill. We mainly talk about the achievement of grinding attachment in large-scale and introduce the typical examples at home and abroad.

  2. Analysis of Temperature Field and Thermal Crown of Roll During Hot Rolling by Simplified FEM

    GUO Zhong-feng; LI Chang-sheng; XU Jian-zhong; LIU Xiang-hua; WANG Guo-dong


    Thermal crown of roll is an important factor, which affects strip profile. It is necessary to analyze the temperature field and thermal crown of roll for hot strip mill. A new simplified finite element method (FEM) was used to analyze the temperature field and thermal crown of roll, and corresponding models were built according to the practical boundary conditions. Transient roll temperature field and thermal crown were simulated by ANSYS FEM software with considering transient thermal contact and complex boundary condition. Temperature and thermal crown variations on roll surface nodes were obtained. The thermal crown results of roll obtained by FEM simulation were in good agreement with the measured data, indicating that simplified FEM models and results were correct.

  3. Effects of finishing rolling temperatures and reduction on the mechanical properties of hot rolled multiphase steel

    LI Zhuang; WU Di


    Effects of finishing rolling temperatures and reduction on the mechanical properties of hot rolled multiphase steel were investigated. Thermo-mechanical control processing (TMCP) was conducted by using a laboratory hot rolling mill, in which three different kinds of finishing rolling temperatures and reduction and various austempering times were applied. The results showed that polygonal ferrite, granular bainite and larger amount of stabilized retained austenite can be obtained by controlled rolling processes, and that the strain-induced transformation to martensite from the retained austenite can occur gradually when the steel is deformed during tensile test. Mechanical properties increase with decreasing finishing rolling temperature and increasing amount of deformation. The most TRIP (transformation induced plasticity) effect, and ultimate tensile strength (UTS), total elongation (TEL) and the product of ultimate tensile strength and total elongation (UTS× TEL) are obtained at 20 min.

  4. Effect of plate asymmetric rolling parameters on the change of the total unit pressure of roll

    A. Kawalek


    Full Text Available This work shows the results of theoretical analysis of asymmetric rolling process of plates in the finishing mill of plate rolling. Its aim was to determine the influence of asymmetry velocity of working rolls on decrease of unit pressure of metal on the rolls. The lower value of the unit pressure will reduce the elastic deflection of the finishing stand and improve the cross-section shape of plate. Three-dimensional simulation of asymmetric hot rolling of S355J2G3 steel plates was done with the aid of FORGE 2008® software. The tensor polynomial interpolation was used for comparing the values of the unit pressure obtaining from symmetric and asymmetric rolling.

  5. SASS Applied to Optimum Work Roll Profile Selection in the Hot Rolling of Wide Steel

    Nolle, Lars

    The quality of steel strip produced in a wide strip rolling mill depends heavily on the careful selection of initial ground work roll profiles for each of the mill stands in the finishing train. In the past, these profiles were determined by human experts, based on their knowledge and experience. In previous work, the profiles were successfully optimised using a self-organising migration algorithm (SOMA). In this research, SASS, a novel heuristic optimisation algorithm that has only one control parameter, has been used to find the optimum profiles for a simulated rolling mill. The resulting strip quality produced using the profiles found by SASS is compared with results from previous work and the quality produced using the original profile specifications. The best set of profiles found by SASS clearly outperformed the original set and performed equally well as SOMA without the need of finding a suitable set of control parameters.

  6. Manufacturing processes 2 grinding, honing, lapping

    Klocke, Fritz


    Presents a view of the most common machining and non-machining manufacturing processes. This volume describes the characteristics of abrasive tools, their design and manufacturing, followed by the fundamentals of grinding fluids. It also discusses grinding of different materials (steel, cast iron, hard and brittle materials, nickel and titanium).

  7. Precision diamond grinding of ceramics and glass

    Smith, S.; Paul, H.; Scattergood, R.O.


    A new research initiative will be undertaken to investigate the effect of machine parameters and material properties on precision diamond grinding of ceramics and glass. The critical grinding depth to initiate the plastic flow-to-brittle fracture regime will be directly measured using plunge-grind tests. This information will be correlated with machine parameters such as wheel bonding and diamond grain size. Multiaxis grinding tests will then be made to provide data more closely coupled with production technology. One important aspect of the material property studies involves measuring fracture toughness at the very short crack sizes commensurate with grinding damage. Short crack toughness value`s can be much less than the long-crack toughness values measured in conventional fracture tests.

  8. Progressive hull removal from barley using the Fitzpatrick comminuting mill

    The objective of the study was to explore an alternative use of the Fitzpatrick Comminuting Machine: to use it to remove the hull from hulled barley while keeping the barley kernel intact. Traditionally, this mill is used to grind material, but we have recently discovered that it also has the abili...


    Douglas Batista Mazzinghy


    Full Text Available The mining industry is famous for many paradigms regarding different flowsheet designs and the use of new technologies and equipment. In this context, a question often performed to process engineers is: what grinding circuit is more efficient, the direct or the reverse? A precise answer could only be given by experimental data and simulations. Simulations were performed using ModSimTM software considering parameters obtained by batch mill tests of an iron ore sample. The simulations, preliminarily, indicated no significant differences between the two circuit configurations for the sample tested. Subsequently, tests were conducted on a pilot scale with detailed measurement of all the variables necessary for a correct interpretation of the differences between the direct and reverse circuits. The test results confirmed the prediction obtained by simulation. This work provides the basis to test other ores and to understanding better the real differences between grinding circuit configurations. Thus, it is expected that some myths of the mineral industry, with respect to flowsheet choices, are overcome.

  10. Crystalline silica dust and respirable particulate matter during indoor concrete grinding - wet grinding and ventilated grinding compared with uncontrolled conventional grinding.

    Akbar-Khanzadeh, Farhang; Milz, Sheryl; Ames, April; Susi, Pamela P; Bisesi, Michael; Khuder, Sadik A; Akbar-Khanzadeh, Mahboubeh


    The effectiveness of wet grinding (wet dust reduction method) and ventilated grinding (local exhaust ventilation method, LEV) in reducing the levels of respirable crystalline silica dust (quartz) and respirable suspended particulate matter (RSP) were compared with that of uncontrolled (no dust reduction method) conventional grinding. A field laboratory was set up to simulate concrete surface grinding using hand-held angle grinders in an enclosed workplace. A total of 34 personal samples (16 pairs side-by-side and 2 singles) and 5 background air samples were collected during 18 concrete grinding sessions ranging from 15-93 min. General ventilation had no statistically significant effect on operator's exposure to dust. Overall, the arithmetic mean concentrations of respirable crystalline silica dust and RSP in personal air samples during: (i) five sessions of uncontrolled conventional grinding were respectively 61.7 and 611 mg/m(3) (ii) seven sessions of wet grinding were 0.896 and 11.9 mg/m(3) and (iii) six sessions of LEV grinding were 0.155 and 1.99 mg/m(3). Uncontrolled conventional grinding generated relatively high levels of respirable silica dust and proportionally high levels of RSP. Wet grinding was effective in reducing the geometric mean concentrations of respirable silica dust 98.2% and RSP 97.6%. LEV grinding was even more effective and reduced the geometric mean concentrations of respirable silica dust 99.7% and RSP 99.6%. Nevertheless, the average level of respirable silica dust (i) during wet grinding was 0.959 mg/m(3) (38 times the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit value [TLV] of 0.025 mg/m(3)) and (ii) during LEV grinding was 0.155 mg/m(3) (6 times the ACGIH TLV). Further studies are needed to examine the effectiveness of a greater variety of models, types, and sizes of grinders on different types of cement in different positions and also to test the simulated field lab experimentation in the field.

  11. Development of centrifugal casting high speed steel rolls

    Hanguang Fu; Aimin Zhao; Jiandong Xing


    The present study aims at developing the high speed steel (HSS) as roll materials to replace the traditional roll materials such as the alloy cast iron and powder metallurgical (PM) hard alloy. The HSS roll billet was formed by centrifugal casting, and the billet was rough machined after soften annealing heat treatment, then it was quenched and tempered to get suitable hardness and toughness. After that the HSS roll was finish machined to the final dimension of φ285 mm in the outer diameter, φ160 mm in the inner diameter and 120 mm in width and its surface hardness was tested. Finally the HSS roll was used in high speed wire rod mill. The test results show that a high and homogeneous hardness can obtain on the work surface of HSS rolls, the surface hardness is 63-65HRC and its variation is smaller than 2HRC. The impact toughness of this kind of HSS is about 16 J/cra2. The results of on-line service investigation in high speed wire rod mill indicate that the HSS rolls have excellent wear resistance, the steel rolling quantity per mm of HSS rolls is 3120 t, the service life-span of HSS rolls is 4 times longer than that of high chromium cast iron rolls and it is close to that of the PM hard alloy rolls. The manufacturing burden of HSS rolls is obviously lower than that of the PM hard alloy rolls, it is only 25% of that of the PM hard alloy rolls.

  12. A study on centrifugal casting of high speed steel roll


    High speed steel (HSS) rolls can replace traditional rolls such as alloyed cast iron rolls and powder metallurgical (PM) hard alloy rolls. The main reasons for the replacement are that the wear resistance of low-cost alloyed cast iron rolls is poor and the cost of high-quality PM hard alloy rolls is very high. By means of centrifugal casting, HSS rolls having excellent wear resistance have been manufactured. The hardness of the HSS roll is 65~ 67 HRC, the range of variation is smaller than 2 HRC and its impact toughness is 15 J/cm2. The wear rate of HSS rolls used in the pre-finishing stands of high-speed hot wire-rod rolling mill reaches 2.5 × 10-4 mm per ton steel. Furthermore, the manufacturing cost of HSS rolls is significantly lower than that of PM hard alloy rolls; it is only 30 percent of that of PM hard alloy rolls.

  13. NBCM with Flat Roll in the Finish Stand

    Xiangwei KONG; Hezhou YE; Jianzhong XU; Guodong WANG; Xianghua LIU; Junwei ZHANG


    With the development of the market, it becomes a demanding task for producers to make flexible production schedules to shorten production cycle. Schedule-free rolling is needed. If the CVC work roll of the F6 and F7 stands in certain 2050 mm hot rolled strip mill are substituted by flat roll (aim to SFR) and the strip profile is controlled by the existing bending force, the control ability is not adequate. This fact has been tested through on-line experiment and has been given in this article. The NBCM (new backup roll crowning method) is recommended to improve the profile control ability. Finally the plastic deformation of the strip and the elastic deformation of the roll are analyzed by employing coupled calculation of rigid-plastic finite element method and G-function method, and the optimal range of the crown of backup roll is given theoretically.

  14. Progress in abrasive and grinding technology

    Xu, Xipeng


    The grinding and abrasive processing of materials are machining techniques which use bonded or loose abrasives to remove material from workpieces. Due to the well-known advantages of grinding and abrasive processes, advances in abrasive and grinding technology are always of great import in enhancing both productivity and component quality. In order to highlight the recent progress made in this field, the editor invited 21 world-wide contributions with the aim of gathering together all of the achievements of leading researchers into a single publication. The authors of the 21 invited papers, of

  15. The Inlet Engine Valves Grinding Using Different Types of Cutting Fluids and Grinding Wheels

    Eraldo Jannone da Silva


    Full Text Available In this paper an experimental research is presented in which different types of cutting fluids (a cutting oil and three different types of soluble oils and grinding wheels (alumina and vitrified CBN were tested in the inlet engine valves grinding. As evaluation parameters the workpiece residual stress and the grinding wheel wear were analyzed. The cutting fluid and the grinding wheel types adopted resulted in changes in all the parameters, due to the different lubricant abilities among the fluids and due to the differences in the mechanical and thermal properties among the abrasives tested. For grinding this steel, the CBN wheel is the best choice, mainly due to compressive residual stress results obtained for all cutting fluids tested. The cutting oil is the most adequate cutting fluid to be used, due to its higher lubricity and ability in keeping the wheel sharp for longer periods of time, reducing the overall grinding energy and the thermal damage.

  16. A new transducer for roll gap measurements of the roll pressure distribution and the friction condition in cold flat rolling

    Lagergren, Jonas; Wanheim, Tarras; Presz, W.


    Background/purpose The only way to establish the true rolling pressure and the true friction condition in cold rolling is to conduct measurements in the roll bite. A new transducer design is therefore proposed, this to overcome problems in previous measurements in the past 70 years. Method The new...... idea is to increase the contact surface of the transducer, to be larger than the arc of contact. This is in the opposite way, compared to the smaller and smaller contact pin design that has been prevailing. Results The measurements where conducted during cold dry rolling of both copper strips...... and stainless steel strips in a pilot mill. The recordings were selected from a steady state with no disturbance from the material flow. The transducer was able to simultaneously measure both the normal pressure and the friction stress. An estimation of the coefficient of friction was accordingly performed...

  17. Effect of Controlled Cooling After Hot Rolling on Mechanical Properties of Hot Rolled TRIP Steel

    WU Di; LI Zhuang; L(U) Hui-sheng


    A three-step cooling pattern on the runout table (ROT) was conducted for the hot rolled TRIP steel. Microstructural evolution during thermomechanical controlled processing (TMCP) was investigated. Proeessing condition of controlled cooling on a ROT in the laboratory rolling mill was discussed. The results indicated that the microstructure containing polygonal ferrite, granular bainite and a significant amount of the stable retained austenite can be obtained through three-step cooling on the ROT after hot rolling. TMCP led to ferrite grain refinement. Controlled cooling after hot rolling resulted in the stability of the remaining austenite and a satisfactory TRIP effect. Excellent mechanical properties were obtained through TMCP for the hot rolled TRIP steel.

  18. Research on the rolling moment in the symmetrical and asymmetrical rolling process

    Alexa, V.; Raţiu, S. A.; Kiss, I.; Cioată, C. G.


    Research distribution the rolling moments symmetrical and asymmetrical report presents great importance both in theory and to introduce clarifications to the calculation of rolling resistance line assemblies. Clarifying individuals of metallic material deformation between the rolls single cylinder diameters act of any difference of work and analysis of advance and delay phenomena. Torque drive value for each of the rolling cylinders was done by reducing the thickness of the laminate samples, an experimental facility located in the laboratory of plastic deformation of the Faculty of Engineering Hunedoara. The analysis of research results show that in terms of power consumption for deformation and safety equipment in operation is rational for mills which require such a difference between the work rolls to execute about one cylinder operated.

  19. 宝钢1580热连轧精轧机 F1~F7安全销试验研究%Development of Safety Pin on the Baosteel 1580 F1~F7 Hot Rolling Finishing Mill



    Briefly introducing the development of the process of the safety pin on the Baosteel 1580 F1 ~F7 hot rolling finishing mill,and achieving the localization of production of the safety pin according to the compo-nent analysis,experiment research,metallographic analysis test,and shearing experiment.%简要介绍了宝钢1580热连轧精轧机 F1~F7安全销的研制过程,通过成份分析、试验研究、金相组织分析、剪切试验等完成安全销的国产化。

  20. Multiparameter Optimization and Controlling for Cylindrical Grinding Process


    This paper bursts the bondage of conventional no-burn thought, presents an optimum strategy permitting burn appear in grinding roughing stage, but the burning layer can be summed on the following finishing stage. On the base of the basic grinding models, the objective function and constrained functions for the multiparameter optimum grinding models had been built in this paper. By the computer simulation, the nonlinear optimum grinding control parameters had been obtained, and the truth grinding process had...

  1. High Efficiency ELID Grinding of Garnet Ferrite


    Hard and brittle materials such as ferrite, optical glass and ceramics have been widely used in many fields because of their good characteristics and still gain more attentions. However, it is difficult to machine and get good surface quality. Some parts made of these materials have large machining allowances and need to be produced with large batch, but the machining efficiency is very low with usual grinding method. So it is of great importance to research the high efficiency grinding technology of hard ...


    Alper ÖZKAN


    Full Text Available In this study, the kinetics of dry and wet grinding of various feed sizes of chromium ore has been determined using a laboratory scale ceramic ball mill. In addition, the effect of pulp density on the spesific rate of breakage (Si and net production rate to finer than specified size were investigated. The dry and wet grinding of all the size intervals of chromium ore followed the first-order breakage law, and the Si values increased as the feed sizes became coarser. Moreover, the wet grinding of these various feed sizes gave higher Si values by a factor of 2.0 to 2.6 comparing to the dry Si values. From the experimental studies performed on the effect of pulp density on the grinding process, the highest Si value was obtained at a pulp density of 45 % solids by volume. At the same pulp density value, the rate of net production of -75 µm particle size also reached the highest value.

  3. 冷轧机附加倾斜后双侧非对称轧制力的计算%Asymmetric Roll Force Calculation With Additional Tilt for Drive Side and Operator Side of Cold Strip Mill

    刘宝权; 张鸿; 王自东; 王军生; 张岩


    对冷轧带钢轧制过程中因辊缝倾斜调整过量所导致的单边浪缺陷和断带进行了分析,应用影响函数法计算辊系变形,通过迭代计算出附加倾斜后的传动侧轧制力、操作侧轧制力、辊间压力分布、单位宽度轧制力分布、出口厚度横向分布、出口横向张应力分布。理论计算和实际测量结果表明,冷轧机双侧轧制力差值与倾斜调整量呈近似线性增长的规律。根据轧制力差值与倾斜量之间的比例关系,用实测轧制力差值对倾斜值进行动态限幅,可有效避免冷轧过程中断带事故的发生。%The single edge wave and strip break caused by excessive tilting adjustment were analyzed. Influence func tion method was adopted to model the roll deformation. Adding different tilt, roll force of drive side, roll force of operator side, transverse distribution of contact pressure between rolls, transverse distribution of roll force, trans verse distribution of strip thickness at exit side and transverse distribution of tension at exit side were calculated by using iterative method. The theoretical calculation and the actual measurement results show that the difference be- tween the bilateral increases almost linearly with tilt adjustment value. The break strip accidents are effectively aver ted by dynamic limiting to tilt setting value with the measured differential roll force, according to the proportional relationship between the differential roll force and the tilt.

  4. Mirror Surface Grinding of Steel Bonded Carbides


    The steel bonded carbide, a composite material, is very difficult to be machined to a fine finish mirror surface. In this paper, an electrolytic in-process dressing (ELID) grinding with metallic bond super-hard abrasive wheel was developed for grinding steel bonded carbide GT35. Factors affecting ELID grinding performance were analyzed by an atomic force microscope (AFM). Based on the analysis of AFM topography of the fine ground mirror surface of the steel bonded carbide, a schematic diagram of the mechanism of micro-removal of the ground surface was described. The AFM topography also shows that the hard brittle carbide particles, on the surface of steel bonded carbide, were machined out by ductile cutting. Since the grinding cracks in the ground surface are due to temperature gradient, temperature distribution in the grinding area was analyzed by finite element method (FEM). Experimental results indicate that a good mirror surface with Ra<0.02pm can be obtained by the developed ELID grinding system.

  5. Comparison of Grinding Characteristics of Converter Steel Slag with and without Pretreatment and Grinding Aids

    Jihui Zhao


    Full Text Available The converter steel slag cannot be widely used in building materials for its poor grindability. In this paper, the grinding characteristics of untreated and pretreated (i.e., magnetic separation steel slag were compared. Additionally, the grinding property of pretreated steel slag was also studied after adding grinding aids. The results show that the residues (i.e., oversize substance that passed a 0.9 mm square-hole screen can be considered as the hardly grinding phases (HGP and its proportion is about 1.5%. After the initial 20 min grinding, the RO phase (RO phase is a continuous solid solution which is composed of some divalent metal oxides, such as FeO, MgO, MnO, CaO, etc., calcium ferrite, and metallic iron phase made up most of the proportion of the HGP, while the metallic iron made up the most component after 70 min grinding. The D50 of untreated steel slag could only reach 32.89 μm after 50 min grinding, but that of pretreated steel slag could reach 18.16 μm after the same grinding time. The grinding efficiency of steel slag was obviously increased and the particle characteristics were improved after using grinding aids (GA, especially the particle proportions of 3–32 μm were obviously increased by 7.24%, 7.22%, and 10.63% after 40 min, 50 min, and 60 min grinding, respectively. This is mainly because of the reduction of agglomeration and this effect of GA was evidenced by SEM (scanning electron microscope images.

  6. Underground void filling by cemented mill tailings

    Choudhary Bhanwar Singh; Kumar Santosh


    Underground mining always create voids. These voids can cause subsidence of surface. So it is always a demand to fill the void in such a manner that the effect of underground mining can be minimized. Void filling using mill tailings especially in metal mining is one of the best techniques. The tailings produced in milling process have traditionally been disposed in tailing ponds creating a waste disposal and environ-mental problems in terms of land degradation, air and water pollution, etc. This disposal practice is more acute in the metal milling industry where the fine grinding, required for value liberation, results in the production of very fine tailings in large percentage. This paper includes discussions on the effectiveness of different paste mixes with varying cement contents in paste backfilling operations. The results revealed that material composition and use of super plasticizer strongly influenced the strength of cemented backfill.

  7. Tandem strip mill's multi-parameter coupling dynamic modeling based on the thickness control

    Peng, Yan; Zhang, Yang; Sun, Jianliang; Zang, Yong


    The rolling process is determined by the interaction of a number of different movements, during which the relative movement occurs between the vibrating roll system and the rolled piece, and the roll system's vibration interacts with the strip's deformation and rigid movement. So many parameters being involved leads to a complex mechanism of this coupling effect. Through testing and analyzing the vibration signals of the mill in the rolling process, the rolling mill's coupled model is established with comprehensive consideration of the coupling interaction between the mill's vertical vibration, its torsional vibration and the working roll's horizontal vibration, and vibration characteristics of different forms of rolling mill's vibration are analyzed under the coupling effect. With comprehensive attention to the relationship between the roll system, the moving strip and the rolling parameters' dynamic properties, and also from the strip thickness control point of view, further research is done on the coupling mechanism between the roll system's movement and the moving strip's characteristics in the rolling process. As a result, the law of inertial coupling and the stiffness coupling effect caused by different forms of the roll system's vibration is determined and the existence of nonlinear characteristics caused by the elastic deformation of moving strip is also found. Furthermore, a multi-parameter coupling-dynamic model is established which takes the tandem strip mill as its research object by making a detailed kinematics analysis of the roll system and using the principle of virtual work. The coupling-dynamic model proposes the instruction to describe the roll system's movement, and analyzes its dynamic response and working stability, and provides a theoretical basis for the realization of the strip thickness' dynamic control.


    WAN Daping; HU Dejin; WU Qi; ZHANG Yonghong


    Automatic compensation of grinding wheel wear in dry grinding is accomplished by an image based online measurement method. A kind of PC-based charge-coupled device image recognition system is schemed out, which detects the topography changes of the grinding wheel surface. Profile data, which corresponds to the wear and the topography, is measured by using a digital image processing method. The grinding wheel wear is evaluated by analyzing the position deviation of the grinding wheel edge. The online wear compensation is achieved according to the measure results. The precise detection and automatic compensation system is integrated into an open structure CNC curve grinding machine. A practical application is carried out to fulfil the precision curve grinding. The experimental results confirm the benefits of the proposed techniques, and the online detection accuracy is less than 5 μm. The grinding machine provides higher precision according to the in-process grinding wheel error compensation.

  9. A Review of Literature on analysis of JIG Grinding Process

    Sudheesh, P. K.; Puthumana, Govindan


    in jig grinding, because of their uniformity and purity. In this paper, abrief review of the analysis of jig grinding process considering various research trends is presented. The areas highlighted are: optimization, selection of abrasives, selection of processing conditions and practical considerations......Jig grinding is a process practically used by tool and die makers in the creation of jigs or mating holes and pegs on dies.The abrasives normally used in jig grinding are divided into Natural Abrasives and Artificial Abrasives. Artificial Abrasiveare preferred in manufacturing of grinding wheels....... The optimization of parameters in jig grinding process is important to maximize productivity and to improve quality. The abrasives of hard jig grinding wheels get blunt quickly so these are recommended to grind workpiece of low hardness and soft grinding wheels are recommended for hard material workpieces. The jig...

  10. Research on the processing speed of cam grinding

    Peng, Baoying; Han, Qiushi


    Cam Grinding is a special kind of non-circular machining. The processing speed of cam grinding has a major influence on cam machining precision. In this paper, decomposed the X-axis feed speed and C-axis velocity by the tangential speed and normal speed in accordance with the curvature circle at the point of cam profile grinding. Proposed the cam grinding processing speed model and linear velocity calculation formula, the processing experiment on the CNC camshaft grinding machine results show that the cam grinding speed model is correct. Constant angular speed grinding and constant linear speed grinding are analyzed respectively, which provides a theoretical basis for cam grinding processing speed optimization.

  11. Surface integrity of GH4169 affected by cantilever finish grinding and the application in aero-engine blades

    Li Xun


    Full Text Available GH4169 is the main material for aero-engine blades and integrated blisks. Because GH4169 has a poor milling performance, the profile precision and surface integrity of blades and integrated blisks are difficult to be met by utilizing the conventional milling process, which directly influence the global performance and reliability of aero-engines. Through grinding experiments on parameters and surface integrity optimization, the helical cantilever grinding process utilizing a 300# CBN RB wheel is presented and applied in finish machining of GH4169 blades. The profile errors of the blade surface are within ±0.01 mm, the roughness is less than 0.4 μm, the residual compressive stresses and the hardening rate are appropriate, there are no phenomena of burr and smearing with the grinding chips, and the leading/trailing edge can be smoothly connected with the suction/pressure surface. All the experimental results indicate that this grinding process is greatly suitable for the profile finish machining of GH4169 blades.

  12. Surface integrity of GH4169 affected by cantilever finish grinding and the application in aero-engine blades

    Li Xun; Ma Shuang; Meng Fanjun


    GH4169 is the main material for aero-engine blades and integrated blisks. Because GH4169 has a poor milling performance, the profile precision and surface integrity of blades and integrated blisks are difficult to be met by utilizing the conventional milling process, which directly influence the global performance and reliability of aero-engines. Through grinding experiments on parameters and surface integrity optimization, the helical cantilever grinding process utilizing a 300# CBN RB wheel is presented and applied in finish machining of GH4169 blades. The profile errors of the blade surface are within ±0.01 mm, the roughness is less than 0.4 lm, the residual compressive stresses and the hardening rate are appropriate, there are no phenomena of burr and smearing with the grinding chips, and the leading/trailing edge can be smoothly connected with the suction/pressure surface. All the experimental results indicate that this grinding process is greatly suitable for the profile finish machining of GH4169 blades.

  13. Rolling Process Modeling Report. Finite-Element Model Validation and Parametric Study on various Rolling Process parameters

    Soulami, Ayoub [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Paxton, Dean M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burkes, Douglas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum alloy plate-type fuel for high-performance research reactors in the United States. This work supports the U.S. Department of Energy National Nuclear Security Administration’s Office of Material Management and Minimization Reactor Conversion Program. This report documents modeling results of PNNL’s efforts to perform finite-element simulations to predict roll-separating forces for various rolling mill geometries for PNNL, Babcock & Wilcox Co., Y-12 National Security Complex, Los Alamos National Laboratory, and Idaho National Laboratory. The model developed and presented in a previous report has been subjected to further validation study using new sets of experimental data generated from a rolling mill at PNNL. Simulation results of both hot rolling and cold rolling of uranium-10% molybdenum coupons have been compared with experimental results. The model was used to predict roll-separating forces at different temperatures and reductions for five rolling mills within the National Nuclear Security Administration Fuel Fabrication Capability project. This report also presents initial results of a finite-element model microstructure-based approach to study the surface roughness at the interface between zirconium and uranium-10% molybdenum.

  14. Analysis of the thermal profile of work rolls in the hot strip rolling process

    Xuanli Zhang; Jie Zhang; Xiaoyan Li; Haixia Li; Gangcheng Wei


    A 2-dimension axisymmetric model was developed by the finite-difference method, which can be used to predict the transient temperature field and thermal profile of work rolls in the hot strip rolling process. To demonstrate the accuracy and reliability of the solution developed, the calculation results were compared with the production data of a 1700 mm hot strip rolling mill and good agreement was found between them. The effect of strip width and roll shifting on the thermal expansion of the work rolls was studied.It is found that the strip width has marked effect on the efficient thermal crown. Initially, when the rolling strip changes from narrow to wide, a bigger efficient thermal crown can be quickly achieved; afterwards, when the rolling strip changes from wide to narrow,not only the influence of uneven wear can be reduced but also the excessive efficient thermal crown can be avoided. It is also found that the work roll shifting has a determinate but not obvious effect on the reduction of the efficient thermal crown, and will make the strip shape unstable without being used properly.

  15. Practice of Improving Roll Deformation Theory in Strip Rolling Process Based on Boundary Integral Equation Method

    Yuan, Zhengwen; Xiao, Hong; Xie, Hongbiao


    Precise strip-shape control theory is significant to improve rolled strip quality, and roll flattening theory is a primary part of the strip-shape theory. To improve the accuracy of roll flattening calculation based on semi-infinite body model, a new and more accurate roll flattening model is proposed in this paper, which is derived based on boundary integral equation method. The displacement fields of the finite length semi-infinite body on left and right sides are simulated by using finite element method (FEM) and displacement decay functions on left and right sides are established. Based on the new roll flattening model, a new 4Hi mill deformation model is established and verified by FEM. The new model is compared with Foppl formula and semi-infinite body model in different strip width, roll shifting value and bending force. The results show that the pressure and flattening between rolls calculated by the new model are more precise than other two models, especially near the two roll barrel edges.


    Huang Yanwei; Wu Tihua; Zhao Jingyi; Wang Yiqun


    A method for the calculation of the sensitivity factors of the rolling process has been obtained by differentiating the roll force model based on support vector machine. It can eliminate the algebraic loop of the analytical model of the rolling process. The simulations in the first stand of five stand cold tandem rolling mill indicate that the calculation for sensitivities by this proposed method can obtain a good accuracy, and an appropriate adjustment on the control variables determined directly by the sensitivity has an excellent compensation accuracy. Moreover, the roll gap has larger effect on the exit thickness than both front tension and back tension, and it is more efficient to select the roll gap as the controlvariable of the thickness control system in the first stand.

  17. Mechanics of Thin Strip Steering in Hot Rolling

    Jiang, Zhengyi; Tieu, Kiet A.


    The hot rolling of thin strip can result in several problems in hot rolling, for instance, the control of strip steering, strip shape and flatness and surface roughness etc. Therefore, the hot rolling of thin strip brings out a requirement of innovative technologies such as the extended control of shape and flatness, steering control and reduction of load by roll gap lubrication. In this paper, the authors focus on the analysis of thin strip snaking movement, as well as solve the related problems such as the shape and flatness due to a larger reduction applied when the strip is thinner. A finite element method was used to simulate this nonsymmetricity rolling considering the non-uniform reduction along the strip width. The calculated spread is compared with the measured values obtained from the rolling mill in laboratory and the friction effect is also discussed.

  18. Temperature Control of Hot Strip Finishing Mill with Inter Stand Cooling

    Sekiguchi, Kunio; Anbe, Yoshiharu; Imanari, Hiroyuki

    It is important for hot strip mill to keep finishing mill delivery temperature to it’s target value because of yield strength and tensile strength of rolled strip. We propose a new method for finishing mill delivery temperature control (FDTC) of a hot strip mill using inter stand strip coolant (ISC). FDTC consists of initial setting (before threading) values calculation of ISC flow rate and finishing mill speed, feed forward FDTC (FF-FDTC) and feedback FDTC (FB-FDTC). The mathematical strip temperature model of finishing mill was identified using normal operating data and some tests. Actual mill application with 7 stands finishing mill showed good FDTC results and also it made possible to increase rolling speed which increase production rate.

  19. An FE Based On-line Model for the Prediction of Work Roll Thermal Profile in Hot Strip Rolling

    Choi, Ji Won; Lee, Jung Hyeung; Sun, Cheng Gang; Hwang, Sang Moo


    Prediction and control of the thermal deformation of the work roll is vital for enhancing product quality in hot strip and plate rolling. In this paper, we present an on-line model for the prediction of the work roll thermal profile. The model is developed on the basis of an integrated finite element model for the coupled analysis of heat transfer and deformation occurring at the bite zone, to rigorously take into account the effect of various rolling parameters on the thermal behavior of the work roll. The validity of the model is demonstrated through comparison with measurements made in an industrial hot strip mill. Also, an emphasis is given to the examination the effect of some selected rolling parameters in an actual production environment.

  20. Effect of Load Distribution on Strip Crown in Hot Strip Rolling

    Hongshuang DI; Jianzhong XU; Dianyao GONG; Xianghua LIU; Guodong WANG; Xiaoming HE; Liying BA


    In order to establish precision model, a software to calculate the strip crown of four-high hot rolling mill was developed by using affecting function method according to the strip crown calculation theory. The effect of work roll diameter, unit width rolling load, roll bending force, work roll crown, initial strip crown and reduction, etc, on load distribution effect rate was simulated by using the software. The results show that the load distribution effect rate increases with the increase of strip width, work roll diameter, unit width rolling load, roll bending force, work roll crown, initial strip crown and reduction. Based on the simulation results, base value of load distribution effect rate and fitting coefficients of six power polynomial of load distribution effect rate modification coefficient were determined considering all of the above parameters. A simplified mathematical model for calculating load distribution effect rate was established.

  1. Reasonable Ball Size of Ball Mill for Preparing Coal Water Fuel and Forecasting Productive Capacity

    张荣曾; 刘炯天; 徐志强; 郑明


    By using the matrix theory, a 5-parameter grinding mathema tical model is established. Based on the properties of feed coal and requirement s for size distribution of final product, the model gives the required grinding probability for various particles and corresponding ball size distribution. By u sing this model, 3 different sizes of ball mill are designed and put into commer cial use for coal water fuel. The forecasted ball mill capacity, the particle si zes and particle size distribution as well as the coal water fuel quality parame ters are all in line with industrial operation results, which have proved the su itability of the model.

  2. Development of a rolling technology for twin-roll cast magnesium strips

    M. Ullmann


    Full Text Available With the best lightweight potential of all metallic construction materials, magnesium primarily helps to increase energy efficiency over the lifecycle of automotive and non-automotive industrial products. Yet to assess overall energy efficiency, the production process must also be taken into account. This paper provides an insight into the energy-efficient production of magnesium strips up to 0,8 mm in thickness based on twin-roll casting and strip rolling on an industrial scale, as developed at the Institute of Metal Forming at the Technical University Bergakademie Freiberg (Germany in cooperation with MgF Magnesium Flachprodukte GmbH (Germ any. The technology of twin-roll casting and strip rolling on a four-high reversing mill is described.

  3. Analysis on the grinding quality of palm oil fibers by using combined grinding equipment

    Gan, H. L.; Gan, L. M.; Law, H. C.


    As known, Malaysia is the second largest palm oil producer worldwide after Indonesia, therefore indicating the abundance of its wastes within the country. The plantation would be seen to increase to at least 5.2 million ha by 2020, and the waste generation would be 50-70 times the plantation. However, the efficiency of bulk density is reduced. This is one of the main reasons of the initiation of this size reduction/ grinding research. With appropriate parameters, grinding will be seen to be helping in enhancing the inter-particle bindings, subsequently increasing the quality of final products. This paper focuses on the grinding quality involving palm oil wastes by using the Scanning Electron Microscope (SEM). The samples would first be ground to powder at varying grinding speed and finally got the randomly chosen particles measured to obtain the size range. The grinding speed was manipulated from 15 Hz to 40 Hz. From the data obtained, it was found the particles fineness increased with increasing grinding speed. In general, the size ranged from 45 μm to about 600 μm, where the finest was recorded at the speed of 40 Hz. It was also found that the binding was not so encouraging at very low speeds. Therefore, the optimum grinding speed for oil palm residues lied in the range of 25 Hz to 30 Hz. However, there were still limitations to be overcome if the accuracy of the image clarity is to be enhanced.

  4. Cross Shear Roll Bonding

    Bay, Niels; Bjerregaard, Henrik; Petersen, Søren. B;


    The present paper describes an investigation of roll bonding an AlZn alloy to mild steel. Application of cross shear roll bonding, where the two equal sized rolls run with different peripheral speed, is shown to give better bond strength than conventional roll bonding. Improvements of up to 20......-23% in bond strength are found and full bond strength is obtained at a reduction of 50% whereas 65% is required in case of conventional roll bonding. Pseudo cross shear roll bonding, where the cross shear effect is obtained by running two equal sized rolls with different speed, gives the same results....

  5. Evaluation of the effects of coal grinding in terms of coal water slurry preparation

    Robak Jolanta


    Full Text Available Coal Water Slurry (CWS is a specific form of solid fuel. It occurs in the form of finely ground coal particles and water. Depending on the use, the content of combustible matter is from 40 to 70% by weight. The attractiveness of the fuel is primarily its properties, i.e. liquid form, high energy efficiency (for water evaporation 4% energy is used – for CSW with 70% concentration of coal, decreased environmental impurities (lower NOx emission and reduced risk of explosion. The advantages of CWS fuels, the possibility of independence from petrochemical fuels, wide availability of coal and emphasis on the use of cleaner technologies are the driving force for development of slurry fuel technologies. The major parameters characterizing the fuel suspension are: solid phase concentration (share of coal in the slurry expressed as either weight or volume fraction of dry coal, time stability (resistance to delamination and separation of the dispersed phase from the continuous phase and viscosity, determining the flow of suspension. The mentioned parameters are dependent on the susceptibility of coal for production of aqueous suspensions (slurrability, conditioned by natural properties of coal, such as: coalification degree, petrographic composition and surface properties. They are also dependent on the slurry fuel preparation process: particle size, solid phase concentration, used additives (stabilizing and dispersion agents and modification of primary coal properties (ash removal, change of surface properties. Preparation of sustainable, high concentrated CWS fuel coal is promoted by the hydrophobic nature of the coal surface, characteristic for coals of higher coalification. A great technological problem is to obtain a highly concentrated coal slurry fuel from less coalified hydrophilic steam coals. The paper presents the results of lab scale research on the CWS prepared from Polish steam coal by wet grinding in mill drum and vibrating. The milling

  6. Multi-stage FE simulation of hot ring rolling

    Wang, C.; Geijselaers, H. J. M.; van den Boogaard, A. H.


    As a unique and important member of the metal forming family, ring rolling provides a cost effective process route to manufacture seamless rings. Applications of ring rolling cover a wide range of products in aerospace, automotive and civil engineering industries [1]. Above the recrystallization temperature of the material, hot ring rolling begins with the upsetting of the billet cut from raw stock. Next a punch pierces the hot upset billet to form a hole through the billet. This billet, referred to as preform, is then rolled by the ring rolling mill. For an accurate simulation of hot ring rolling, it is crucial to include the deformations, stresses and strains from the upsetting and piercing process as initial conditions for the rolling stage. In this work, multi-stage FE simulations of hot ring rolling process were performed by mapping the local deformation state of the workpiece from one step to the next one. The simulations of upsetting and piercing stages were carried out by 2D axisymmetric models using adaptive remeshing and element erosion. The workpiece for the ring rolling stage was subsequently obtained after performing a 2D to 3D mapping. The commercial FE package LS-DYNA was used for the study and user defined subroutines were implemented to complete the control algorithm. The simulation results were analyzed and also compared with those from the single-stage FE model of hot ring rolling.


    E. A. Peretyagina


    Full Text Available Peculiarities of structure formation of steel 80K after austenization with the subsequent cooling with speed ~15 °С/sec within 1-20 seconds and with final cooling in water are studied. The scientifically reasonable energy saving models of a sorbitizing of high-carbon wire rood, which allow to lower energy consumption while maintaining the pace of productions and provision o of the necessary quality and process performance are developed and implemented on the mill 150 OJSC «BSW – MHC «BMC».

  8. Research on Visualization in Scientific Computation of Grinding Temperature Field


    The paper introduces the concepts, classification and method of visualization in scientific computation. Visual C++ developing tool is used to compute surface grinding forces and grinding temperature field models. The three-dimensional entity model of workpiece is made with OpenGL tool, and the different colors on the workpiece entity show different value of temperature, so the visualization of grinding temperature field is realized. The temperature value of every points in grinding temperature field, the c...


    Antonio Augusto Gorni


    Full Text Available The decrease in hot strength or even rolling load as strain increases in some stands of the finishing hot strip mill with no metallurgical reasons is a relatively common event. Apparently this fact is associated with modification in the tribological conditions between rolling stock and work roll surfaces due to unexpected interactions with scale. The aim of this work is to determine the values of the friction coefficient in the several stands of the finishing hot strip mill at Usiminas-Cubatão, as well to determine quantitative relationships between this coefficient and relevant process parameters, like strain degree and peripherical work roll speed.

  10. Study Friction Distribution during the Cold Rolling of Material by Matroll Software

    Abdollahi, H.; Dehghani, K.


    Rolling process is one of the most important ways of metal forming. Since the results of this process are almost finished product, therefore controlling the parameters affecting this process is very important in order to have cold rolling products with high quality. Among the parameters knowing the coefficient of friction within the roll gap is known as the most significant one. That is because other rolling parameters such as rolling force, pressure in the roll gap, forward slip, surface quality of sheet, and the life of work rolls are directly influenced by friction. On the other hand, in rolling calculation due to lake of a true amount for coefficient of friction a supposed value is considered for it. In this study, a new software (Matroll), is introduced which can determine the coefficient of friction (COF) and plot the friction hills for an industrial mill. Besides, based on rolling equations, it offers about 30 rolling parameters as outputs. Having the rolling characteristics as inputs, the software is able to calculate the coefficient of friction. Many rolling passes were performed on real industrial aluminum mill. The coefficient of friction was obtained for all passes. The results are in good agreement with the findings of the other researchers.

  11. Effection of grinding system rigidity ultra-precision grinding of aspheric mould and error compensation

    Yin, S. H.; Gong, S.


    In ultra-precision oblique axis grinding process for machining micro aspherical mould, form error of aspherical surface is caused by the inconsistence elastic deformation of grinding system, which derived from differences velocity from inside to out. In this case, whole PV value can meet requirements, however, pits are produced in central after error compensation, which is unworkable. In this paper, mechanism of machining error caused by grinding system rigidity is analyzed, and experiments are carried out. Form error compensation grinding are carried out in the central local area, based on traditional error compensation method, which can effectively eliminate the pits of surface center. In this method, cemented carbide YG8 which diameter is about 6mm is ground. The results showed that the form accuracy under PV 200 nm and under PV 50 nm within the scope of 1 mm, and the surface roughness under Ra2nm.

  12. 改进的量子遗传算法在冷连轧机负荷分配中的应用研究%Application research on improved quantum genetic algorithm for load distribution optimization of tandem cold rolling mill

    姜万录; 张生


    量子遗传算法可以克服常规遗传算法迭代次数多、易陷入局部极值的缺点,本文研究并改进了量子遗传算法的量子门旋转角度更新策略,提高了量子遗传算法的性能.应用标准函数测试表明,改进后的量子遗传算法收敛速度快,全局寻优能力更强.将改进的量子遗传算法应用于冷连轧机的负荷分配优化过程,根据Bland-Ford轧制理论以功率和轧制力均衡分配为目标建立综合目标函数,试验数据对比证明,量子遗传算法优化所得的轧制参数比经验分配和常规遗传算法优化所得结果更为合理,符合轧制工艺要求.因此,利用量子遗传算法对冷连轧机进行负荷分配优化是一种有效可行的新方法.%A quantum genetic algorithm is introduced for load distribution of tandem cold rolling mill in order to avoid the shortcomings of genetic algorithm, such as more iterations, slow convergence and easily trapped into local minima.A new adjusting strategy of quantum rotational gate is proposed for improving the performance of quantum genetic algorithm.It is shown by standard function tests and data comparison that the improved quantum genetic algorithm can avoid the premature convergence, has stronger ability of global optimization, and is an effective method for the optimization of the load distribution of tandem cold rolling mill.

  13. A new speed optimization algorithm with application in pickling and rolling line

    Xiaoyan Zhu


    Full Text Available In order to reduce equipment wear and operator pressure, as well as to improve the production efficiency of combined continuous pickling line and tandem cold rolling mill units, four sections’ speeds should be automatically optimized to control the three loopers’ abundance, which include the entry loopers’ entry speed, pickling speed, trimming speed, and tandem cold rolling mill entry speed. According to the optimal speed principle, a new optimization algorithm was proposed based on objective function. In this work, Nelder–Mead simplex method is applied to find the optimal solution by minimizing the objective function. In addition, the calculation of four initial speeds is specified, especially the initial tandem cold rolling mill entry speed. The proposed speed optimization algorithm was successfully applied to a 1450 mm continuous pickling line and tandem cold rolling mill. The acceleration and deceleration are smooth and steady when welding, trimming, or roll changing takes place in practice, the three loopers’ abundance are controlled in suitable range. Results show that the continuous pickling line unit could provide the material in maximum capacity to ensure that the tandem cold rolling mill unit’s production is efficient, and the rolling yield is greatly improved due to the decrease in the number of stops.

  14. Recent developments in semiprocessed cold rolled magnetic lamination steel

    Hilinski, E. J.


    Over the past 10 years the magnetic property performance of semi-processed cold rolled magnetic lamination steels in North America have approached those of nonoriented, semi-processed silicon steel. This improvement was accomplished via higher alloy levels in conjunction with hot band annealing. New temper rolling strategies can produce weakly oriented steels tailored to specific applications, such as small transformers used in fluorescent lighting ballasts. Recently, production trials for 0.0138 in product cold rolled on tin mills has been undertaken. Efforts to further improve properties through a better understanding of texture control and via implementation of new production processes, such as thin slab or strip casting, continue.

  15. Recrystallization model for hot-rolling of 5182 aluminum alloy


    A recrystallization model for hot-rolling of 5182 aluminum alloy was presented by means of the fractional softening during double interval deformation. It is found that the recrystallization rate depends on strain rate more sensitively than deformation temperature, and the time for full recrystallization is very short as strain rate is greater than 1 s-1. Using the recrystallization—time—temperature curves, the desirable hot rolled microstructure can be obtained by controlling the rolling speed, temperature and cooling rate before cooling during the last pass in reversing mill.

  16. VCR and ASR technology for profile and flatness control in hot strip mills

    CAO Jian-guo; WEI Gang-cheng; ZHANG Jie; CHEN Xian-lin; ZHOU Yi-zhong


    The roll contour pattern and variety of work and backup roils in service and its effect on profile and flatness control performance in 1 700 mm hot strip mill at Wuhan Iron and Steel (Group) Corporation were tested and analyzed by the developed finite element models of different typical roll contours configurations. A rather smooth local work roll contour near strip edges and an increase in rolled length can be obtained by application of long stroke work roll shifting system with conventional work roll contours that is incapable of the crown control. In comparison with the conventional backup and work roll contours configuration, the crown control range by the roll bending force enhances by 12.79% and the roll gap stiffness increases by 25.26% with the developed asymmetry self-compensating work rolls(ASR) and varying contact backup rolls(VCR). A better strip profile and flatness quality, an increase in coil numbers within the rolling campaign and a significant alleviated effect of severe work roll wear contours on performance of edge drop control are achieved by the application of ASR with crown control and wear control ability in downstream stand F5 and VCR in all stands of 1 700 mm hot strip mill.

  17. Method of accurate grinding for single enveloping TI worm

    SUN; Yuehai; ZHENG; Huijiang; BI; Qingzhen; WANG; Shuren


    TI worm drive consists of involute helical gear and its enveloping Hourglass worm. Accurate grinding for TI worm is the key manufacture technology for TI worm gearing being popularized and applied. According to the theory of gear mesh, the equations of tooth surface of worm drive are gained, and the equation of the axial section profile of grinding wheel that can accurately grind TI worm is extracted. Simultaneously,the relation of position and motion between TI worm and grinding wheel are expounded.The method for precisely grinding single enveloping TI worm is obtained.

  18. Study of pulmonary (lung) functioning of commercial wheat grinding machine operators in India using spirometric testing.

    Agashe, Abhijeet; Deshpande, V S


    In ancient times, in India each household had a chakki to mill the wheat. There was no concept of getting wheat grounded from outside. With the fast changing lifestyle, this tradition has almost disappeared now. Today every city of India has numerous commercial wheat grinding machine shops located at various places. Other than states like Punjab, this occupation is mostly unorganized and little has been done to look into the welfare and health of these machine operators. Like most of the occupations, this occupation of wheat grinding also has several occupational hazards and injuries associated with it. The most obvious of them all in this case is due to the continuous exposure of the operators to the rising dust wheat particles, commonly called atta). This perpetual inhaling ofpollutants exposes the operators to risks of pulmonary malfunctioning. Therefore, this paper attempts to determine the pulmonary functioning of the commercial wheat grinding machine operators in India using spirometric testing. On the basis of the anthropometric data, effort has been done to develop the expected lung performance. Further, the actual lung performance of the operators is measured and compared with expected performance.

  19. Grinding Characteristic of Multi-walled Carbon Nanotubes-alumina Composite Particle

    B MUNKHBAYAR; Nasan BAYARAA; Hafizur REHMAN; Junhyo KIM; Hanshik CHUNG; Hyomin JEONG


    The synthesis of new materials containing multi-walled carbon nanotubes (MWCNTs) and the microstructure of alumina particles were investigated and characterized.The MWCNTs and alumina particles were ground under both the dry and wet conditions with various rotation speeds (200-400 r/min) in planetary ball milling machine,and their combination characteristics were described.The experimental results were examined by scanning electron microscopy (SEM),X-ray diff action (XRD),transmission electron microscopy (TEM) and particle sizing analysis (PSA).SEM result revealed that the combination of MWCNTs -Alumina particles mixed quite well under both the dry and wet grinding with rotation speed of 400 r/min.XRD characterization indicated the better result could get in ground samples at a rotation speed of 400 r/min.PSA result showed the particle size decreased with increase the grinding speeds.From the overall results,we observed that the grinding method can be used to synthesize new material with high efficiency.

  20. Microstructure and texture of asymmetrically rolled aluminium and titanium after deformation and recrystallization

    Wronski, M.; Wierzbanowski, K.; Wronski, S.; Bacroix, B.


    Asymmetric rolling is used to modify material properties and to reduce forces and torques applied during deformation. This geometry of deformation is relatively easy to implement on existing industrial rolling mills and it can provide large volumes of a material. The results of the study of microstructure and crystallographic texture in asymmetrically rolled aluminium 6061 and titanium (grade 2) are presented in this work. These characteristics were determined using the EBSD technique and X-ray diffraction. The rolling asymmetry was realized using two identical rolls, driven by independent motors, rotating with different angular velocities. It was found that asymmetric rolling leads to microstructural refinement and texture rotation (around the transverse direction). The impact of asymmetric rolling on microstructural refinement appears also in recrystallized samples of both materials. On the other hand, texture rotation, caused by asymmetric rolling, persists after annealing in titanium but not in aluminium samples.

  1. Analysis of CVC roll contour and determination of roll crown

    Guang Xu; Xianjun Liu; Jiarong Zhao; Junwei Xiong


    Mathematical analysis of continuous variable crown (CVC) roll contour used in CSP production line was conducted and the roll contour function of CVC roll was obtained. The validation with actual CVC roll contour shows that the calculation values of the roll contour function and the actual roll contour parameters given by equipment provider are the same, which proves that the roll contour function of CVC rolls given in this article is correct. The nonlinear relationship between the roll crown of CVC rolls and roll shift amounts was deduced. The concept of crown extremum was given.



    In accordance with the difficult problems of belt cross vibrations and effects of belt tension on machine spindle precision in abrasive belt grinding, a new soft grinding wheel is put forward, which is provided with the advantages of belt grinding and can be installed directly on the grinding machine spindle substituting for common grinding wheels. The new soft grinding wheel does not need any ancillary facilities and dressing devices in grinding. With analyzing error of wheel and grinding experiment, the highefficiency grinding characteristics grinding hardbrittle materials has been obtained.

  3. Research on CNC Turning System of Aspheric Machining Grinding Wheel

    ZOU Qin; GUO Yin-biao


    The technology of machining aspheric surface with high precision is the premise for the application of aspheric surface. The grinding machining with error compensation is a commonly used method to machine aspheric surface, which will directly influence the quality of aspheric workpiece surface. Multifunctional CNC grinding wheel truing system is a four-axis CNC truing system which can be applied to grinding wheel truing. In this system,DSP-based multi-axes motion control card is adopted as the controller, and visual C++ is used as development tool.When the design of hardware and software is completed, the system can implement truing of various grinding wheel with high precision aspheric machining such as plane grinding wheel, arc grinding one, and sphere grinding one.

  4. Validation of the Hot Strip Mill Model

    Richard Shulkosky; David Rosberg; Jerrud Chapman


    The Hot Strip Mill Model (HSMM) is an off-line, PC based software originally developed by the University of British Columbia (UBC) and the National Institute of Standards and Technology (NIST) under the AISI/DOE Advanced Process Control Program. The HSMM was developed to predict the temperatures, deformations, microstructure evolution and mechanical properties of steel strip or plate rolled in a hot mill. INTEG process group inc. undertook the current task of enhancing and validating the technology. With the support of 5 North American steel producers, INTEG process group tested and validated the model using actual operating data from the steel plants and enhanced the model to improve prediction results.

  5. Prediction of temperature distribution in the hot rolling of slabs

    Serajzadeh, S.; Karimi Taheri, A.; Mucciardi, F.


    In the process of continuous hot slab rolling, it is vital to know the temperature distribution within the slab along the length of the rolling mill because temperature is the dominant parameter controlling the kinetics of metallurgical transformations and the flow stress of the rolled metal. In other words, the microstructural changes, the mechanical properties as well as the final dimensions of the product and roll-force depend on the temperature distribution within the metal being rolled. In this paper, a mathematical model based on the finite element method is utilized to predict the temperature distribution and microstructural changes during the continuous hot slab rolling process. The effects of various parameters such as the heat of deformation, the work-roll temperature, the rolling speed, and the heat transfer coefficient between the work-roll and the metal are all taken into account in the analyses. To verify the validity of the model and the generated computer code, a comparison is carried out between the theoretical and plant-recorded results.

  6. In-Orbit Construction with a Helical Seam Pipe Mill

    Gilhooley, N.

    The challenges of building large structures in space, and in particular a torus habitat, require novel processes. One potential method is to manufacture helical seam (also called spiral) pipe in orbit using a pipe mill. These machines turn rolls of steel or alloy into fully formed, welded and inspected pipe, pressure vessels and silos of various diameters. Pipe mills are highly automated and efficient in a factory environment and are increasingly being used for in-situ repair. By constructing in-orbit (on-orbit assembly) the launch vehicle can supply full payloads of compact, robust rolls of material; and the installation design is less restricted by fairing constraints and modular limitations. The use of a pipe mill is discussed as a possible construction method, for comparison an example design envelope is shown and further pipe mill products are considered.

  7. Recrystallization of niobium stabilized ferritic stainless steel during hot rolling simulation by torsion tests

    Flávia Vieira Braga


    Full Text Available The aim of this study was to investigate the effect of finishing hot rolling temperature in promoting interpass recrystallization on a Nb-stabilized AISI 430 ferritic stainless steel. Torsion tests were performed in order to simulate the Steckel mill rolling process by varying the temperature ranges of the finishing passes. Interrupted torsion test were also performed and interpass recrystallization was evaluated via optical microscopy and electron backscatter diffraction (EBSD. As a result of this work, it has been established, within the restrictions of a Steckel mill rolling schedule, which thermomechanical conditions mostly favor SRX.

  8. Quality Control system for a hot-rolled metal surface

    I. Mazur


    Full Text Available The modern ideas about of quality of products are based on the principle of the absolute satisfaction of requirements of recommendations of the buyer. A presence of surface defects of steel-smelting and rolling origin is peculiar to the production of hot-rolling mill. The automatic surface inspection system (ASIS includes two digital line video cameras for the filming of the upper and lower surfaces of the flat bar, block of illumination of the upper and lower surfaces of the flat bar, computer equipment. A system that secures 100 % control of the surface of rolled metal (of the upper and lower side detects automatically and classifies the sheet defects in the real time mode was mounted in the domestic practice in the first time in 2003 on hot rolling mill 2000 JSC «Novolipetsk Iron & Steel Corporation» (NISC. The whole assortment of the mill 2000 was divided for the five groups by the outward appearance of the surface. The works on the identification of defects of hot-rolled metal and widening of data base of knowledge of ASIS were continued after the carrying out of guarantee tests. More than 10 thousand images of defects were added to the data base during the year.

  9. Rolling Force Prediction in Heavy Plate Rolling Based on Uniform Differential Neural Network

    Fei Zhang


    Full Text Available Accurate prediction of the rolling force is critical to assuring the quality of the final product in steel manufacturing. Exit thickness of plate for each pass is calculated from roll gap, mill spring, and predicted roll force. Ideal pass scheduling is dependent on a precise prediction of the roll force in each pass. This paper will introduce a concept that allows obtaining the material model parameters directly from the rolling process on an industrial scale by the uniform differential neural network. On the basis of the characteristics that the uniform distribution can fully characterize the solution space and enhance the diversity of the population, uniformity research on differential evolution operator is made to get improved crossover with uniform distribution. When its original function is transferred with a transfer function, the uniform differential evolution algorithms can quickly solve complex optimization problems. Neural network structure and weights threshold are optimized by uniform differential evolution algorithm, and a uniform differential neural network is formed to improve rolling force prediction accuracy in process control system.

  10. System Analysis of Flat Grinding Process with Wheel Face

    T. N. Ivanova


    Full Text Available The paper presents a conducted system analysis of the flat grinding wheel face, considers the state parameters, input and output variables of subsystems, namely: machine tool, workpiece, grinding wheel, cutting fluids, and the contact area. It reveals the factors influencing the temperature and power conditions for the grinding process.Aim: conducting the system analysis of the flat grinding process with wheel face expects to enable a development of the system of grinding process parameters as a technical system, which will make it possible to evaluate each parameter individually and implement optimization of the entire system.One of the most important criteria in defining the optimal process conditions is the grinding temperature, which, to avoid defects appearance of on the surface of component, should not exceed the critical temperature values to be experimentally determined. The temperature criterion can be useful for choosing the conditions for the maximum defect-free performance of the mechanical face grinding. To define the maximum performance of defect-free grinding can also use other criteria such as a critical power density, indirectly reflecting the allowable thermal stress grinding process; the structure of the ground surface, which reflects the presence or absence of a defect layer, which is determined after the large number of experiments; flow range of the diamond layer.Optimal conditions should not exceed those of defect-free grinding. It is found that a maximum performance depends on the characteristics of circles and grade of processed material, as well as on the contact area and grinding conditions. Optimal performance depends on the diamond value (cost and specific consumption of diamonds in a circle.Above criteria require formalization as a function of the variable parameters of the grinding process. There is an option for the compromise of inter-criteria optimality, thereby providing a set of acceptable solutions, from


    Raj K. Rajamani; Sanjeeva Latchireddi; Sravan K. Prathy; Trilokyanath Patra


    The U.S. mining industry operates approximately 80 semi-autogenesis grinding mills (SAG) throughout the United States. Depending on the mill size the SAG mills draws between 2 MW and 17 MW. The product from the SAG mill is further reduced in size using pebble crushers and ball mills. Hence, typical gold or copper ore requires between 2.0 and 7.5 kWh per ton of energy to reduce the particle size. Considering a typical mining operation processes 10,000 to 100,000 tons per day the energy expenditure in grinding is 50 percent of the cost of production of the metal. A research team from the University of Utah is working to make inroads into saving energy in these SAG mills. In 2003, Industries of the Future Program of the Department of Energy tasked the University of Utah team to build a partnership between the University and the mining industry for the specific purpose of reducing energy consumption in SAG mills. A partnership was formed with Cortez Gold Mines, Kennecott Utah Copper Corporation, Process Engineering Resources Inc. and others. In the current project, Cortez Gold Mines played a key role in facilitating the 26-ft SAG mill at Cortez as a test mill for this study. According to plant personnel, there were a number of unscheduled shut downs to repair broken liners and the mill throughput fluctuated depending on ore type. The University team had two softwares, Millsoft and FlowMod to tackle the problem. Millsoft is capable of simulating the motion of charge in the mill. FlowMod calculates the slurry flow through the grate and pulp lifters. Based on this data the two models were fine-tuned to fit the Cortez SAG will. In the summer of 2004 a new design of shell lifters were presented to Cortez and in September 2004 these lifters were installed in the SAG mill. By December 2004 Cortez Mines realized that the SAG mill is drawing approximately 236-kW less power than before while maintaining the same level of production. In the first month there was extreme cycling

  12. Experimental Setup for Diamond Grinding Using Electrochemical InProcess Controlled Dressing (ECD of Grinding Wheel

    M. A. Shavva


    Full Text Available The most effective method for finish machining of hard-metals and alloys is to use the diamond grinding wheels for grinding. An application of diamond wheels significantly increases the employee output, reduces costs, and raises manufacturing efficiency with achieving the high performance properties of treated surfaces.During grinding a working surface of diamond wheel wears out. It adversely affects the cutting capability of the diamond grains, and depending on the grinding conditions can occur through different mechanisms. Wear of diamond wheel causes distortion of its shape and reduces cutting properties. However, dressing of diamond wheels is a complicated and time-consuming operation in terms of manufacturing technique.Methods to make dressing of diamond grinding wheel have different types of classification. Classification of dressing methods by the type of energy used is as follows: mechanical, chemical, electrophysical, electromechanical, and electrochemical. All these methods have their advantages and disadvantages.Electrochemical method of dressing is the most productive and efficient. Electrochemical method comprises anode-mechanical dressing and electrochemical (electrolytic one. The paper presents the electrochemical in-process dressing (ECD and the electrolytic in-process dressing (ELID.The source of energy, grinding a wheel with metal bond, and an electrode are necessary for providing ELID. The ELID consists of several stages. The first stage is preliminary electrolytic dressing of diamond wheel. The electrolyte is placed into the gap between the wheel and electrode. The bond of the wheel is oxidized. An insulating layer is formed. It reduces an electrical conductivity of the wheel and controls consumption of diamond grains, as well as polishes the surface of the work piece. Further, the insulating layer is destroyed. The cycle of dressing begins anew.The ECD proceeds in the same way as ELID. However during the ECD-process there

  13. Development and Application of Die-Casting High Speed Steel Rolls

    JIANG Zhi-qiang; FU Han-guang; DING Yu-cheng


    Due to its high hardness, good red hardness and excellent wear resistance at high temperature, high speed steel (HSS) is fit for the roll manufacture. In order to overcome the segregation of centrifugal casting of HSS roll, die-cast processes were developed and its effects on the properties of the HSS roll were investigated. It was found that pressure, pressing time and speed are three important factors affecting shrinkage cavity. For pouring temperature of 1 400-1 450 ℃, pressure of 150-160 MPa, pressing time of 120-150 s and pressing speed of 14-16 mm/s, a compact HSS roll was obtained, which has no segregation and small working allowance. In the high speed wire rod rolling mill, service life of the HSS roll is 5 to 8 times longer than that of high nickel chromium infinite chilled cast iron roll.

  14. Hybrid Hot Strip Rolling Force Prediction using a Bayesian Trained Artificial Neural Network and Analytical Models

    Abdelkrim Moussaoui


    Full Text Available The authors discuss the combination of an Artificial Neural Network (ANN with analytical models to improve the performance of the prediction model of finishing rolling force in hot strip rolling mill process. The suggested model was implemented using Bayesian Evidence based training algorithm. It was found that the Bayesian Evidence based approach provided a superior and smoother fit to the real rolling mill data. Completely independent set of real rolling data were used to evaluate the capacity of the fitted ANN model to predict the unseen regions of data. As a result, test rolls obtained by the suggested hybrid model have shown high prediction quality comparatively to the usual empirical prediction models.

  15. Study on the New Grinding Fluids of Oils on Water

    魏源迁; 钱怡; 中村隆; 松原十三生


    To fulfill a zero-emission in the process of grinding and thoroughly eliminate the influences of the conventional grinding fluids on the eco-environment as well as save up electric energy and reduce in production costs, the new grinding fluids of botanic oils on water were developed, in which a lot of tiny water droplets attached with micro oil films were blown to the machining area by a compressing air-jet so good as to produce lubricating and cooling roles.In this study, grinding performances of the new fluids were investigated by comparison to the conventional ones such as emulsion on the plane NC grinder.

  16. Separate critical condition for ultrasonic vibration assisted grinding

    ZHANG; Hong-li; ZHANG; Jian-hua


    Separate characteristic of the tangential ultrasonic vibration assisted grinding(TUAG)machining is analyzed based on TUAG process, and a critical speed formula is given to correctly set the machining parameters to insure the separate characteristics of TUAG process. The critical speed is not only related to the ultrasonic vibration amplitude and frequency, but also to the grinding wheel velocity and the cutting point space, and the grinding force can be decreased during the TUAG process with separability. Grinding force experiments are conducted, and the experimental results are in good agreement with the theoretical results.

  17. Process parameter dependent growth phenomena of naproxen nanosuspension manufactured by wet media milling.

    Bitterlich, A; Laabs, C; Krautstrunk, I; Dengler, M; Juhnke, M; Grandeury, A; Bunjes, H; Kwade, A


    The production of nanosuspensions has proved to be an effective method for overcoming bioavailability challenges of poorly water soluble drugs. Wet milling in stirred media mills and planetary ball mills has become an established top-down-method for producing such drug nanosuspensions. The quality of the resulting nanosuspension is determined by the stability against agglomeration on the one hand, and the process parameters of the mill on the other hand. In order to understand the occurring dependencies, a detailed screening study, not only on adequate stabilizers, but also on their optimum concentration was carried out for the active pharmaceutical ingredient (API) naproxen in a planetary ball mill. The type and concentration of the stabilizer had a pronounced influence on the minimum particle size obtained. With the best formulation the influence of the relevant process parameters on product quality was investigated to determine the grinding limit of naproxen. Besides the well known phenomenon of particle agglomeration, actual naproxen crystal growth and morphology alterations occurred during the process which has not been observed before. It was shown that, by adjusting the process parameters, those effects could be reduced or eliminated. Thus, besides real grinding and agglomeration a process parameter dependent ripening of the naproxen particles was identified to be a concurrent effect during the naproxen fine grinding process.

  18. Thermo-mechanical properties of bowl-shaped grinding wheel and machining error compensation for grinding indexable inserts

    张祥雷; 姚斌; 陈彬强; 孙维方; 王萌萌; 罗琪


    In order to meet the technical requirements of grinding the circumferential cutting edge of indexable inserts, thermo-mechanical properties of bowl-shaped grinding wheel in high speed grinding process and the influence of dimension variations of the grinding wheel on machining accuracy were investigated. Firstly, the variation trends of the dimension due to centrifugal force generated in different wheel speeds were studied and the effect of stress stiffening and spin softening was presented. Triangular heat flux distribution model was adopted to determine temperature distribution in grinding process. Temperature field cloud pictures were obtained by the finite element software. Then, dimension variation trends of wheel structure were acquired by considering the thermo-mechanical characteristic under combined action of centrifugal force and grinding heat at different speeds. A method of online dynamic monitoring and automatic compensation for dimension error of indexable insert was proposed. By experimental verification, the precision of the inserts satisfies the requirement of processing.

  19. Frequency Modulation of High-Speed Mill Chatter


    Mill chatter is a common phenomenon in the metal strip rolling process. Product defects caused by mill vibration were reported worldwide during last two decades, which is usually classified as torque vibration of the driving system with low frequencies and vertical vibration of the mill stand with comparative higher frequencies. The frequency range of the vertical vibration is wide (in general from more than 100 Hz to more than 1 000 Hz), and the vibration phenomena are very complex, even it is very diffic...

  20. 升速轧制对热轧带钢层流冷却出口温度的影响%Influence of Accelerating Rolling on the Laminar Cooling Exit Temperature in Hot Strip Mill

    张大志; 叶海丽; 项晓菲; 谢新亮; 李红霞; 高广


    采用传热学原理建立了层流冷却温度有限差分模型,并用现场实测数据对水冷换热系数进行了自适应修正.对德盛1 150 mm热轧带钢层流冷却过程的温度变化进行了数值模拟,建立了一套层流冷却温度仿真系统,分析和研究升速轧制时带钢在层流冷却中温度变化的趋势.结果表明,层冷出口温度受带钢的速度影响较大,在升速过程中,如果不采用集管动态喷水调节,带钢温度出现前低后高的现象,并且随着加速度的增加带钢前后温差越大.以此为依据,现场过程自动化系统L2级硬件采用过程服务器,基础自动化系统L1级硬件采用西门子PLC,L2级和L1级软件分别在C++和Step7V5.4下编程实现,并采用了带钢头尾宏跟踪和过程自动化系统采用带钢样本微跟踪的控制策略,对处于变速及高速运动中的带钢沿长度方向逐点实施控制,用动态调节的冷却集管系统来保证在速度变化期间带钢层流冷却出口温度的稳定性.%The principle of heat transfer is adopted for the strip temperature finite difference model and the heat transfer coefficient of water is amended based on measured data.The temperature change is numerically simulated in the process of Desheng 1 150 mm hot strip laminar cooling.The simulation system is established to study the change trend of laminar cooling temperature in accelerating rolling.Results show that the coil temperature is significantly influenced by the speed of strip,the strip temperature gradually increases from the front to the back,and the temperature deviation increases with the acceleration without dynamic regulation of the cooling pipe system during acceleration.Based on the conclusions,the L2-level hardware is a process server,the L1-level hardware is Siemens PLC for the online control system and the softwares of L1 and L2 are programmed by C++ and Step7V54.The successful control strategy online tracking of head and tail of

  1. Evaluation of roll compaction as a preparation method for hydroxypropyl cellulose-based matrix tablets

    Imjak Jeon


    Full Text Available Roll compaction was applied for the preparation of hydroxypropyl cellulose (HPC-based sustained-release matrix tablets. Matrix tablets made via roll compaction exhibited higher dosage uniformity and faster drug release than direct-compacted tablets. HPC viscosity grade, roll pressure, and milling speed affected tablet properties significantly. Roll compaction seems to be an adequate granulation method for the preparation of HPC-based matrix tablets due to the simplicity of the process, less handling difficulty from HPC tackiness as well as easier particle size targeting. Selecting the optimum ratio of plastic excipients and the particle size of starting materials can however be critical issues in this method.

  2. Influence of Hot Deformation and Subsequent Austempering on the Mechanical Properties of Hot Rolled Multiphase Steel

    Zhuang LI; Di WU


    Influence of hot deformation and subsequent austempering on the mechanical properties of hot rolled multiphase steel was investigated. Thermo-mechanical control processing (TMCP) was conducted by using a laboratory hot rolling mill, where three different kinds of finishing rolling reduction, and austemperings with various isothermal holding duration were applied. The results have shown that a multiphase microstructure consisting of polygonal ferrite, granular bainite and larger amount of stabilized retained austenite can be obtained by controlled rolling processes. Mechanical properties increase with increasing the amount of deformation because of the stabilization of retained austenite. Ultimate tensile strength (σb), total elongation (δ)36% and 28476 MPa%, respectively) at optimal processes.

  3. Simulation of Hot Strip-Rolling Process Based on Dislocation Density Variation

    XIAO Hong; ZHANG Guo-min; CHEN Zhan-fu


    Based on the variation of dislocation density, which is influenced by rolling variables in hot strip-rolling process, a yield stress model was constructed. An integrated model was built to predict the temperature variation and microstructure evolution, in which the Orowan formula was used to calculate the stress and strain, and the finite difference method was adopted to determine the temperature field. This model was applied to predict the temperature variation, austenite grain size and phase transformation in hot strip-rolling process, and the prediction results are in good agreement with the measured ones on 2 050 mm continuous hot strip-rolling mill.

  4. Third Rolling Mill in a Factory Improvement Project 6 kV Reactive Power Compensation and Harmonic Control%某厂改造工程6kV供电系统无功补偿与谐波治理

    刘义友; 吴方达; 徐芸; 刘宾


    High-power rectifier.inverter,energy-saving lamp etc equipment can produce large amounts harmonic current, and influence the normal operation of the equipment. Combined with the power play the flat line load characteristics, overviewed the third rolling mill in a factory 6 kV power system improvement project reactive power compensation and harmonic design. The scheme select high-pressure FC type filter and reactive compensation device to make the harmonic current most inflows filter circuits. After analysis and calculation, the actual filter effect proof the effect is obvious, after running,can absorb the most harmonic,can raise grid power factor, less investment, high economic benefit.%大功率的整流器、变频器、节能灯等设备会产生大量谐波电流,影响设备的正常运行,结合弹扁生产线的用电负荷特点,概述了某厂改造工程6 kV供电系统无功补偿与谐波治理的设计方案,该方案选用高压FC型滤波及无功补偿装置,使谐波电流大部分流入滤波回路.经过分析计算,投运后滤波效果实测证明效果明显,能够将谐波大部分吸收,同时还提高电网功率因数,投资少,经济效益高.

  5. Adaptive Automatic Gauge Control of a Cold Strip Rolling Process

    ROMAN, N.


    Full Text Available The paper tackles with thickness control structure of the cold rolled strips. This structure is based on the rolls position control of a reversible quarto rolling mill. The main feature of the system proposed in the paper consists in the compensation of the errors introduced by the deficient dynamics of the hydraulic servo-system used for the rolls positioning, by means of a dynamic compensator that approximates the inverse system of the servo-system. Because the servo-system is considered variant over time, an on-line identification of the servo-system and parameter adapting of the compensator are achieved. The results obtained by numerical simulation are presented together with the data taken from real process. These results illustrate the efficiency of the proposed solutions.

  6. Quenching simulation of steel grinding balls

    Zapata-Hernandez, O.; Reyes, L. A.; Camurri, C.; Carrasco, C.; Garza-Monte-de-Oca, F.; Colas, R.


    The phase transformations of high carbon steel during quenching and equalizing were modelled using commercial computer packages based on the finite element method and the kinetic transformation of steel. The model was used to predict the temperature and microstructural changes taking place within balls of two different sizes that are used for grinding mineral ores. A good correlation between the temperatures measured by inserted thermocouples and those predicted by the model was obtained after modifying the thermal conductivity of the steel within the temperature domain at which mixed phases are present. The phase transformations predicted were confirmed by metallographic analyses. (Author)

  7. Rolling Shutter Motion Deblurring

    Su, Shuochen


    Although motion blur and rolling shutter deformations are closely coupled artifacts in images taken with CMOS image sensors, the two phenomena have so far mostly been treated separately, with deblurring algorithms being unable to handle rolling shutter wobble, and rolling shutter algorithms being incapable of dealing with motion blur. We propose an approach that delivers sharp and undis torted output given a single rolling shutter motion blurred image. The key to achieving this is a global modeling of the camera motion trajectory, which enables each scanline of the image to be deblurred with the corresponding motion segment. We show the results of the proposed framework through experiments on synthetic and real data.

  8. Wet gringing of zeolite in stirred media mill

    Mucsi, G.; Bohács, K.


    In the present study the results of systematic experimental series are presented with the specific goal of optimizing the zeolite nanoparticles' production using a wet stirred media mill. The diameter of the grinding media as well as the rotor velocity were varied in the experiments. Particle size distribution and "outer" specific surface area of the ground samples were measured by a laser particle size analyser. Additionally, BET, XRD and FT-IR analyses were performed for the characterization of the "total" specific surface area as well as the crystalline and material structure, respectively. Based on the results of the laboratory experiments it was found that wet stirred media milling provided significant reductions in the particle size of zeolite. Furthermore, the crystallinity of the samples also decreased, so not only the physical but the mineralogical characteristics of zeolite can be controlled by stirred media milling.


    HE Anrui; YANG Quan; CHEN Xianlin; ZHAO Lin


    Varying contact-length backup roll and linearly variable crown work roll are provided for improving the mill performance of profile and flatness control. Integrated with theses technologies, relevant profile and flatness control models are developed for hot strip mills on the basis of large amount of finite element calculation. These models include shape setup control model in process control system, bending force feedforward control model, crown feedback control model and flatness feedback control model in basis automation system. Such a profile and flatness control system with full functions is applied in 1 700 mm industrial hot strip mills of Ansteel. Large amount of production data shows that the crown precision with the tolerance of (18 (m is over 90%, the strip percentage which the actual flatness is within ( 25 I-unit surpasses 96%, and general roll consume is reduced by 28% by using the profile and flatness control system. In addition, schedule-free rolling is realized.

  10. Occlusal Grinding Pattern during Sleep Bruxism and Temporomandibular Disorder

    Yeni Wijaya


    Full Text Available Sleep Bruxism is a significant etiology of temporomandibular disorder (TMD and causes many dental or oral problems such as tooth wear or facet. There is no study analyzing the relationship between sleep bruxism and TMD. Objective: To investigate any relationship between occlusal grinding pattern during sleep bruxism and temporomandibular disorder. Methods: A cross-sectional study involving 30 sleep bruxism patients attended the Faculty Dentistry Universitas Indonesia Teaching Hospital (RSGMP FKG UI. Completion of 2 forms of ID-TMD index and questionnaire from American Academy of Sleep Medicine were done. BruxChecker was fabricated and used for two nights to record the occlusal grinding pattern. The occlusal grinding pattern was categorized into laterotrusive grinding (LG and mediotrusive side. Further divisons of LG were: incisor-canine (IC, incisor-caninepremolar (ICP and incisor-canine-premolar-molar (ICPM. Mediotrusive side was classified as mediotrusive contact (MC and mediotrusive grinding (MG. Results: It was found that occlusal grinding pattern in non-TMD subjects were IC+MC, in subjects with mild TMD were ICP+MG and in subjects with moderate TMD were ICP+MG and ICPM+MG. TMJ was more significantly affected by ICP and ICPM grinding pattern than that of IC. Conclusion: There was a significant relationship between occlusal grinding pattern during sleep bruxism and TMD.DOI: 10.14693/jdi.v20i2.149

  11. Stochastic dynamic programming applied to planning of robot grinding tasks

    Brown, M.L. (Digital Equipment Corp., Shrewsbury, MA (United States)); Whitney, D.E. (Massachusetts Inst. of Technology, Cambridge, MA (United States))


    This paper proposes an intelligent manufacturing system that can make decisions about the process in light of the uncertain outcome of these decisions and attempts to minimize the expected economic penalty resulting from those decisions. It uses robot weld bead grinding as an example of a process with significant process variations. The need for multiple grinding passes, the poor predictability of those passes, the task requirements, and the process constraints conspire to make planning and controlling weld bead grinding a formidable probe. A three tier hierarchical control system is proposed to plan an optimal sequence of grinding passes, dynamically simulate each pass, execute the planned sequence of controlled grinding passes, and modify the pass sequence as grinding continues. The top tier, described in this paper, plans the grinding sequence for each weld bead, and is implemented using Stochastic Dynamic Programming, selecting the volumetric removal and feedspeed for each pass in order to optimize the satisfaction of the task requirements by the entire grinding sequence within the equipment, task, and process constraints. The resulting optimal policies have quite complex structures, showing foresight, anxiety, indifference, and aggressiveness, depending upon the situation.

  12. 7 CFR 58.726 - Cutting and grinding.


    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Cutting and grinding. 58.726 Section 58.726 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Procedures § 58.726 Cutting and grinding. The trimmed and cleaned cheese should be cut into sections...

  13. Computer Simulation of Batch Grinding Process Based on Simulink 5.0

    LI Xia; YANG Ying-jie; DENG Hui-yong; HUANG Guang-yao


    How to use Simulink software in grinding system was studied. The method of designing batch grinding subsystem and the steps of building batch grinding blockset were introduced. Based on batch grinding population balance model, batch grinding was simulated with Simulink. The results show that the simulation system designed with Simulink explain reasonably the impersonal rule of batch grinding. On the basis of batch grinding simulation, the computer simulation of mineral processing system with Simulink of grinding and classification, comminution, etc, can be properly explored.

  14. Specific Properties of Air Flow Field Within the Grinding Zone

    ZHENG Junyi; JIANG Zhengfeng; ZHAO Liang


    Air barrier of grinding means a boundary layer of air existing at the circumference of the rotating wheel, which hinders coolant from entry. This paper makes a research on air flow field of the grinding zone through experiments and numerical simulations, focusing on acquainting with the specific properties of the air flow field. Finite volume method is applied to analyze air flow field within grinding wheel in the course of numerical calculations. The test devices such as Hot-wire anemometer and Betz manometer are used during the experiments of testing the pressure and velocity within grinding zone. Results of experiments agree by and large with numerical results of calculations. The conclusions obtained in this paper, the distribution of wall pressure and the distribution of air flow velocity, are important and useful to navigate the delivery of coolant into the grinding zone. In conclusion, some recommendations are made for further study and practical applications in such field.

  15. Monitoring Grinding Wheel Redress-life Using Support Vector Machines

    Xun Chen; Thitikorn Limchimchol


    Condition monitoring is a very important aspect in automated manufacturing processes. Any malfunction of a machining process will deteriorate production quality and efficiency. This paper presents an application of support vector machines in grinding process monitoring. The paper starts with an overview of grinding behaviour. Grinding force is analysed through a Short Time Fourier Transform (STFT) to identify features for condition monitoring. The Support Vector Machine (SVM) methodology is introduced as a powerful tool for the classification of different wheel wear situations.After training with available signal data, the SVM is able to identify the state of a grinding process. The requirement and strategy for using SVM for grinding process monitoring is discussed, while the result of the example illustrates how effective SVMs can be in determining wheel redress-life.

  16. Investigations of spherical grinding parameters on circularity error, finished diameter, and grinding forces for porous polyurethane foam

    Isarawit Chaopanich


    Full Text Available The aim of this study was to examine the effect of grinding variables on the circularity error, finished diameter, andgrinding forces of porous polyurethane foam (PPUF. A cube of PPUF having the size of 21 mm was transformed into a roundshape using a vertical wheel grinding with the circular groove pad developed. The grinding speed (Vs of the wheel wasvaried between 1.41 and 5.18 m/s. The cross head speed of the circular groove pad (f was controlled at 1, 3, 5 mm/min. Theabrasive grit size (A of 20 and 53 μm made of silicon carbide were applied. Two replications of experiment were randomlyperformed. Diameter and circularity error of the ground specimen were determined by vision measuring machine. The tangentialand normal forces of grinding were obtained using a dynamometer. The experimental data were statistically analyzed. The study found that (1 the grinding speed could remarkably affect the circularity error, finished diameter, and grinding forces,(2 the grinding speed ranged between 2.83 and 3.77 m/s could contribute to sphere shape specimens, and (3 the grinding speed of 3.30 m/s, cross head speed of 1 mm/min, and abrasive grit size of 20 μm provided the least circularity error.

  17. Shape Control Simulation on 4-High CVC Mill

    WANG Ying-rui; YUAN Jian-guang; LIU Hong-min


    The computation model of shape and crown on 4 high CVC mill was established by combining the stream surface strip element method for analyzing three-dimensional plastic deformation of strip and the influence coefficient method for elastic deformation of rolls,and the simulation of the shape and crown control on 4-high CVC hot strip mill was conducted.The simulated results indicate that the influence of the shifting of CVC work roll on shape and crown is very large,and the shifting of work roll can be used to preset shape and crown.The influence of the bending force of work roll on shape and crown is smaller,and it is suitable to use the bending force of work roll for shape and crown adjustment on line.With the increase of strip width,the exit crown of strip increases firstly and de creases then,and the roll gap becomes smoother increasingly.Meanwhile,the transverse difference of front tension stress decreases firstly and increases then.

  18. Production of scallop shell nanoparticles by mechanical grinding as a formaldehyde adsorbent

    Yamanaka, Shinya, E-mail: [Muroran Institute of Technology, College of Environmental Technology (Japan); Suzuma, Akifumi [Muroran Institute of Technology, Division of Applied Sciences (Japan); Fujimoto, Toshiyuki; Kuga, Yoshikazu [Muroran Institute of Technology, College of Environmental Technology (Japan)


    Scallop shells, which are a waste product in the seafood industry, are disposed more than 200,000 ton per year in Hokkaido, Japan. We report effective uses and simple application for discarded shells as a formaldehyde adsorbent. The adsorption performance of scallop shells to remove formaldehyde vapor is investigated. Planetary ball milling under dry conditions and subsequent water addition realize shells with a crystallite size (35-90 nm) and equivalent size of the specific surface area (41-191 nm) in the nanometer range. The comminution properties of the scallop shells, especially the grinding limit, are estimated via a semi-theoretical consideration for the grinding limit. Additionally, the adsorbed amount of gaseous formaldehyde using a self-designed adsorption line is estimated. The nanosized scallop shells exhibit an excellent adsorption performance rather than the feed shell, and the adsorbed amount is positively correlated with the specific surface area of the shell. Hence, scallop shells have potential to adsorb volatile organic compounds.

  19. Experimental Studies on Ultrasonic Vibration Grinding of the Workpiece Made from Fine-crystalline Zirconia Ceramics

    WU Yan; ZHU Xun-sheng; ZHAO Bo


    The performances of fine-crystalline zirconia ceramics in workpiece ultrasonic vibration grinding (WUVG) and conventional grinding (CG) with diamond wheel were researched. The effects of WUVG and CG on material removal rate, grinding forces, surface roughness and microstructure of zirconia ceramic were investigated.Experimental results indicated that: (1) The material removal rate (MRR) in ultrasonic grinding process is two times as large as that of in conventional grinding. The material removal rate increases with increasing grinding depth in both ultrasonic grinding and conventional grinding.(2) The ultrasonic vibration grinding force is lower than that of conventional grinding force, and the increase of the worktable speed leads to a decrease of the grinding force,while the grinding force increases with larger grinding depth in both WUVG and CG. (3) The surface of ultrasonic vibration grinding has no spur and build-up edge and its surface roughness is smaller than that of CG significantly.Surface quality of WUVG is superior to that of conventional grinding, it is easy for ultrasonic vibration grinding that material removal mechanism is ductile grinding.

  20. Effect of Thermomechanical Processing on Mechanical Properties of Hot Rolled Multiphase Steel

    LI Zhuang; WU Di; L(U) Hui-sheng


    The effect of thermomechanical processing (TMP) on the mechanical properties of hot rolled multiphase steel was investigated. TMP was conducted using a laboratory hot rolling mill, in which three different kinds of finish rolling deformation degrees and temperatures were applied. The results indicate that polygonal ferrite, granular bainite, and a considerable amount of stabilized retained austenite can be obtained by TMP. The stability of the retained austenite increases with decreasing finish rolling temperature and increasing finish rolling deformation degrees. Ultimate tensile strength (σb), total elongation (δ), and the product of ultimate tensile strength by total elongation (σb·δ) for 50% reduction at finish rolling temperature of 700 ℃ reach maximum values [791 MPa, 36% and 28 476 (MPa·%), respectively].

  1. Improving the Surface Roughness of Pickled Steel Strip by Control of Rolling Temperature

    Chang, Yao-Nan; Lin, Szu-Ning; Liou, Horng-Yih; Chang, Chu-Wei; Wu, Chia-Chan; Wang, Ying-Chun


    This investigation is to analyze the surface roughness problem of low carbon pickled steel strips from the view points of prior hot rolling conditions and the hot-rolled scales. The results showed that, compared with other parameters, the most important factor in hot rolling to affect the surface roughness was the rolling temperature. As the temperature was increased, the amount of the outer brittle α-Fe2O3 increased, leading to rough scale/substrate interface and rough surface after pickling. However, the effect of coiling temperature was almost negligible because no further rolling existed after that stage. Quantitative estimation showed that decrease in rolling temperature in this investigation reduced the surface roughness, Ra, from 1.06-1.78 μm to 0.88-1.10 μm after pickling in laboratory. Similar degree of improvement in roughness was also observed after pickling in mill.

  2. Recent developments in modeling of hot rolling processes: Part I - Fundamentals

    Hirt, Gerhard; Bambach, Markus; Seuren, Simon; Henke, Thomas; Lohmar, Johannes


    The numerical simulation of industrial rolling processes has gained substantial relevance over the past decades. A large variety of models have been put forward to simulate single and multiple rolling passes taking various interactions between the process, the microstructure evolution and the rolling mill into account. On the one hand, these include sophisticated approaches which couple models on all scales from the product's microstructure level up to the elastic behavior of the roll stand. On the other hand, simplified but fast models are used for on-line process control and automatic pass schedule optimization. This publication gives a short overview of the fundamental equations used in modeling of hot rolling of metals. Part II of this paper will present selected applications of hot rolling simulations.

  3. CISM Course on Rolling Contact Phenomena

    Kalker, Joost


    Preface.- Rolling Contact Phenomena - Linear Elasticity.- Finite Element Methods for Rolling Contact.- Plastic Deformation in Rolling Contact.- Non-Steady State Rolling Contact and Corrugations.- Modelling of Tyre Force and Moment Generation.- Rolling Noise.- Lubrication

  4. Modelling and simulation of fixtures during grinding

    Matthias; KLAERNER; Juergen; LEOPOLD; Lothar; KROLL


    The complex workpiece-fixture behaviour during machining is an essential component of the fixture development process.In detail,the forces acting on fixture components have to be analysed.A method for the prediction of the reaction forces due to process and clamping loads is presented in this article.At the beginning,detailed information about the workpiece-fixture behaviour during the process is determined by a complex finite element model.Secondly,the reduction of the number of elements leads to a smaller model with less computation time,validated and used for the variation of process parameters.Finally,an analytical description is developed based on the combination of both results.With the help of the empiric equation it is possible to predict the reaction forces and the dependency on several process parameters.This method has been validated by modelling shape grinding of a nozzle guide vane.

  5. Modelling and simulation of fixtures during grinding

    Matthias KLAERNER; Juergen LEOPOLD; Lothar KROLL


    The complex workpiece-fixture behaviour during machining is an essential component of the fixture development process. In detail, the forces acting on fixture components have to be analysed. A method for the prediction of the reaction forces due to process and clamping loads is presented in this article.At the beginning, detailed information about the workpiece-fixture behaviour during the process is determined by a complex finite element model. Secondly, the reduction of the number of elements leads to a smaller model with less computation time, validated and used for the variation of process parameters. Finally, an analytical description is developed based on the combination of both results.With the help of the empiric equation it is possible to predict the reaction forces and the dependency on several process parameters. This method has been validated by modelling shape grinding of a nozzle guide vane.

  6. Investigation on drilling-grinding of CFRP

    Yanming QUAN; Wenwang ZHONG


    It is difficult to machine polymer matrix composites reinforced by carbon fibre, and the hole-making process is the most necessary machining process for composite plate products. Conventional drills have a very short life in the drilling of this kind of composites and the quality of the hole is very poor. In this paper, the cemented or plated diamond core tools are tested to make holes in carbon fibre/epoxy composite plates. The effects of machining parameters, cooling and chip removal on the tool life, and the hole quality are investigated. The results indicate that the material removal mechanism of the two kinds of diamond tools is not like the cutting effect of the conventional drilling but similar to that of grinding. Satisfactory effects in making holes in the composites are obtained--quite acceptable machined hole quality, low costs, and long wear-resistant endurance.

  7. Grinding temperature and energy ratio coe cient in MQL grinding of high-temperature nickel-base alloy by using di erent vegetable oils as base oil

    Li Benkai; Li Changhe; Zhang Yanbin; Wang Yaogang; Jia Dongzhou; Yang Min


    Vegetable oil can be used as a base oil in minimal quantity of lubrication (MQL). This study compared the performances of MQL grinding by using castor oil, soybean oil, rapeseed oil, corn oil, sunflower oil, peanut oil, and palm oil as base oils. A K-P36 numerical-control precision surface grinder was used to perform plain grinding on a workpiece material with a high-temperature nickel base alloy. A YDM–III 99 three-dimensional dynamometer was used to measure grinding force, and a clip-type thermocouple was used to determine grinding temperature. The grinding force, grind-ing temperature, and energy ratio coefficient of MQL grinding were compared among the seven veg-etable oil types. Results revealed that (1) castor oil-based MQL grinding yields the lowest grinding force but exhibits the highest grinding temperature and energy ratio coefficient;(2) palm oil-based MQL grinding generates the second lowest grinding force but shows the lowest grinding temperature and energy ratio coefficient;(3) MQL grinding based on the five other vegetable oils produces similar grinding forces, grinding temperatures, and energy ratio coefficients, with values ranging between those of castor oil and palm oil;(4) viscosity significantly influences grinding force and grinding tem-perature to a greater extent than fatty acid varieties and contents in vegetable oils;(5) although more viscous vegetable oil exhibits greater lubrication and significantly lower grinding force than less vis-cous vegetable oil, high viscosity reduces the heat exchange capability of vegetable oil and thus yields a high grinding temperature;(6) saturated fatty acid is a more efficient lubricant than unsaturated fatty acid;and (7) a short carbon chain transfers heat more effectively than a long carbon chain. Palm oil is the optimum base oil of MQL grinding, and this base oil yields 26.98 N tangential grinding force, 87.10 N normal grinding force, 119.6 °C grinding temperature, and 42.7%energy ratio coefficient

  8. Agar agar-stabilized milled zerovalent iron particles for in situ groundwater remediation

    Velimirovic, Milica; Schmid, Doris; Wagner, Stephan; Micić, Vesna; Kammer, Frank von der; Hofmann, Thilo, E-mail:


    Submicron-scale milled zerovalent iron (milled ZVI) particles produced by grinding macroscopic raw materials could provide a cost-effective alternative to nanoscale zerovalent iron (nZVI) particles for in situ degradation of chlorinated aliphatic hydrocarbons in groundwater. However, the aggregation and settling of bare milled ZVI particles from suspension presents a significant obstacle to their in situ application for groundwater remediation. In our investigations we reduced the rapid aggregation and settling rate of bare milled ZVI particles from suspension by stabilization with a “green” agar agar polymer. The transport potential of stabilized milled ZVI particle suspensions in a diverse array of natural heterogeneous porous media was evaluated in a series of well-controlled laboratory column experiments. The impact of agar agar on trichloroethene (TCE) removal by milled ZVI particles was assessed in laboratory-scale batch reactors. The use of agar agar significantly enhanced the transport of milled ZVI particles in all of the investigated porous media. Reactivity tests showed that the agar agar-stabilized milled ZVI particles were reactive towards TCE, but that their reactivity was an order of magnitude less than that of bare, non-stabilized milled ZVI particles. Our results suggest that milled ZVI particles could be used as an alternative to nZVI particles as their potential for emplacement into contaminated zone, their reactivity, and expected longevity are beneficial for in situ groundwater remediation. - Highlights: • Rapid aggregation and sedimentation were observed in bare milled ZVI particles. • Agar agar improved the stability of milled ZVI particle suspensions. • Agar agar enhanced the transport of milled ZVI particles in heterogeneous sands. • Agar agar reduced the reactivity of milled ZVI particles towards TCE.

  9. A novel application of α-glucosyl hesperidin for nanoparticle formation of active pharmaceutical ingredients by dry grinding.

    Tozuka, Yuichi; Imono, Masaaki; Uchiyama, Hiromasa; Takeuchi, Hirofumi


    The effectiveness of α-glucosyl hesperidin (Hsp-G) as a novel grinding aid for the preparation of drug nanoparticles by dry grinding was investigated. Poorly water-soluble drugs and Hsp-G were mixed at a weight ratio of 1/5 and ground for 60 min by a vibrational ball mill. It was evident that all poorly water-soluble drugs used in this study formed nanoparticles after the ground mixtures were dispersed into distilled water. The dissolution profile of glibenclamide from the ground mixtures of glibenclamide/Hsp-G showed dramatic improvement from that of untreated drug crystals. Administration of the ground mixture of glibenclamide/Hsp-G to rats resulted in a significantly higher rate of decrease in blood glucose levels than that of untreated glibenclamide. The area above the time-curve of plasma-glucose concentrations using the ground mixture of glibenclamide/Hsp-G was 6-fold higher than that using untreated glibenclamide. The improved dissolution rate due to nanoparticle formation of glibenclamide, induced by co-grinding with Hsp-G, was responsible for this improvement.

  10. Biomass torrefaction mill

    Sprouse, Kenneth M.


    A biomass torrefaction system includes a mill which receives a raw biomass feedstock and operates at temperatures above 400 F (204 C) to generate a dusty flue gas which contains a milled biomass product.

  11. Quantum dice rolling

    Aharon, N.; Silman, J.


    A coin is just a two sided dice. Recently, Mochon proved that quantum weak coin flipping with an arbitrarily small bias is possible. However, the use of quantum resources to allow N remote distrustful parties to roll an N-sided dice has yet to be addressed. In this paper we show that contrary to the classical case, N-sided dice rolling with arbitrarily small bias is possible for any N. In addition, we present a six-round three-sided dice rolling protocol, achieving a bias of 0.181, which inco...

  12. Roll System and Stock's Multi-parameter Coupling Dynamic Modeling Based on the Shape Control of Steel Strip

    Zhang, Yang; Peng, Yan; Sun, Jianliang; Zang, Yong


    The existence of rolling deformation area in the rolling mill system is the main characteristic which distinguishes the other machinery. In order to analyze the dynamic property of roll system's flexural deformation, it is necessary to consider the transverse periodic movement of stock in the rolling deformation area which is caused by the flexural deformation movement of roll system simultaneously. Therefore, the displacement field of roll system and flow of metal in the deformation area is described by kinematic analysis in the dynamic system. Through introducing the lateral displacement function of metal in the deformation area, the dynamic variation of per unit width rolling force can be determined at the same time. Then the coupling law caused by the co-effect of rigid movement and flexural deformation of the system structural elements is determined. Furthermore, a multi-parameter coupling dynamic model of the roll system and stock is established by the principle of virtual work. More explicitly, the coupled motion modal analysis was made for the roll system. Meanwhile, the analytical solutions for the flexural deformation movement's mode shape functions of rolls are discussed. In addition, the dynamic characteristic of the lateral flow of metal in the rolling deformation area has been analyzed at the same time. The establishment of dynamic lateral displacement function of metal in the deformation area makes the foundation for analyzing the coupling law between roll system and rolling deformation area, and provides a theoretical basis for the realization of the dynamic shape control of steel strip.

  13. Ultraprecision, high stiffness CNC grinding machines for ductile mode grinding of brittle materials

    McKeown, Patrick A.; Carlisle, Keith; Shore, Paul; Read, R. F.


    Under certain controlled conditions it is now possible to machine brittle materials such as glasses and ceramics using single or multi-point diamond tools (grinding), so that material is removed by plastic flow, leaving crack-free surfaces. This process is called 'shear' or 'ductile' mode grinding. It represents a major breakthrough in modern manufacturing engineering since it promises to enable: - complex optical components, both transmission and reflecting to be generated by advanced CNC machines with very little (or even zero) subsequent polishing. - complex shaped components such as turbine blades, nozzle guide vanes, etc. to be finish machined after near net shape forming, to high precision in advanced ceramics such as silicon nitride, without inducing micro-cracking and thus lowering ultimate rupture strength and fatigue life. Ductile mode "damage free" grinding occurs when the volume of materials stressed by each grit of the grinding wheel is small enough to yield rather than exhibit brittle fracture, i.e. cracking. In practice, this means maintaining the undeformed chip thickness to below the ductile-brittle transition value; this varies from material to material but is generally in the order of 0.1 pm or 100 nm, (hence the term "nanogrinding" is sometimes used) . Thus the critical factors for operating successfully in the ductile regime are machine system accuracy and dynamic stiffness between each grit and the workpiece. In detail this means: (i) High precision 'truing' of the diamond grits, together with dressing of the wheel bond to ensure adequate ' openness'; (ii) Design and build of the grinding wheel spindle with very high dynamic stiffness; error motions, radial and axial, must be considerably less than 100 nfl. (iii) Design and build of the workpiece carriage motion system with very high dynamic stiffness; error motions, linear or rotary, must be well within 100 nm. (iv) Smooth, rumble-free, high-stiffness servo-drives controlling the motions

  14. Investigation on the Surface Coating of Grinding Balls


    The surface coating of grinding balls was investigated experimentally. The results show that a coating may form on the surface of grinding balls when Cr or Al powders are subjected to ball grinding. The plastic deformation of the ball surface plays an important role during the coating formation, and the strong binding force between the powders and the balls is a necessary pre-condition. The thickness of coating increases with the plasticity of the powders and the balls. Annealing the balls with coating will result in an obvious diffusion of the elements in the bonding zone of inter-face.

  15. Eco-efficiency of grinding processes and systems

    Winter, Marius


    This research monograph aims at presenting an integrated assessment approach to describe, model, evaluate and improve the eco-efficiency of existing and new grinding processes and systems. Various combinations of grinding process parameters and system configurations can be evaluated based on the eco-efficiency. The book presents the novel concept of empirical and physical modeling of technological, economic and environmental impact indicators. This includes the integrated evaluation of different grinding process and system scenarios. The book is a valuable read for research experts and practitioners in the field of eco-efficiency of manufacturing processes but the book may also be beneficial for graduate students.

  16. McCarter superfinish grinding for silicon -- an update.

    Anthony, F.; Khounsary, A.; McCarter, D.; Krasnicki, F.; Tangedahl, M.


    A grinding technique, referred to as the McCarter Superfinish, for grinding large size optical components is discussed and certain surface characterization information about flatness and the relative magnitude of the subsurface damage in silicon substrates is reported. The flatness measurements were obtained with a Zygo surface analyzer, and the substrate damage measurements were made by x-ray diffraction and acid etching. Results indicate excellent control of flatness and fine surface finish. X-ray measurements show that the diamond wheels with small particle sizes used in the final phases of the grinding operation renders surfaces with relatively small subsurface damage.

  17. Fundamentals of grinding : surface conditions of ground WC-Co systems

    Hegeman, JBJW; De Hosson, JTM; Shulepov, SY; Lousberg, N; de With, G; Brebbia, CA; Kenny, JM


    This paper concentrates on the fundamentals of grinding of inorganic materials. A statistical grinding model was developed based on the topography of the grinding wheel. The results of the model are compared with the results of grinding experiments on WC-Co hardmetals. The calculated profiles and me

  18. Research on strip hysteretic behavior and mill vertical vibration system nonlinear dynamics

    Fan, Xiaobin; Zang, Yong; Jin, Ke


    Rolling mill vibration is a technical problem in the iron and steel industry for many years and has serious impact and harm on production. There were serious vibrations in the middle mills when rolling thin container strip for the compact strip production (CSP) strip hot rolling process. This paper studied the hysteretic characteristic of rolled strip and established the vertical vibration system single-degree-of-freedom dynamics model of the F3 mill rollers. The influence of parameters on the system characteristics was studied, such as the linear damping coefficient, linear stiffness coefficient, nonlinear displacement coefficient, nonlinear velocity coefficient and exciting force, and then, the vibration source and vibration-restraining measure were studied from the roll gap. The results show that with increasing linear stiffness, damping and hysteresis coefficient, it can reduce the possibility of chaotic system; the linear stiffness coefficient had the greatest influence, and hysteresis damping coefficient had minimal influence on chaotic threshold. In order to reduce rolling mill vibration amplitude, we should reduce the external excitation force firstly, and in order to improve the dynamic performance of the system, we should control the speed of nonlinear coefficient values. The contrast experiments were carried out at the production scene finally.

  19. Rolling at small scales

    Nielsen, Kim L.; Niordson, Christian F.; Hutchinson, John W.


    The rolling process is widely used in the metal forming industry and has been so for many years. However, the process has attracted renewed interest as it recently has been adapted to very small scales where conventional plasticity theory cannot accurately predict the material response. It is well....... Metals are known to be stronger when large strain gradients appear over a few microns; hence, the forces involved in the rolling process are expected to increase relatively at these smaller scales. In the present numerical analysis, a steady-state modeling technique that enables convergence without...... dealing with the transient response period is employed. This allows for a comprehensive parameter study. Coulomb friction, including a stick-slip condition, is used as a first approximation. It is found that length scale effects increase both the forces applied to the roll, the roll torque, and thus...

  20. Rolled-Up Metamaterials

    Stephan Schwaiger


    Full Text Available In this paper we review metamaterials fabricated from self-rolling strained metal-semiconductor layer systems. These systems relax their strain upon release from the substrate by rolling up into microtubes with a cross-section similar to a rolled-up carpet. We show that the walls of these microtubes represent three-dimensional optical metamaterials which so far could be used, for example, for the realization of broadband hyperlenses, fishnet metamaterials, or optically active three-dimensional metamaterials utilizing the unique possibility to stack optically active semiconductor heterostructures and metallic nanostructures. Furthermore, we discuss THz metamaterials based on arrays of rolled-up metal semiconductor microtubes and helices.


    S.Z. Li; J. Xu; Y.D. Yin; J.G. Xue; F. Pan; J.M. Zheng; J.H. Yoon


    With the aid of FE(finite element) code MSC.Superform 2005, 2-D coupled thermo-mechanical simulation of center-crack occurrence in round billet during 2-roll rotary rolling process was presented using Oyane ductile fracture criteria. A simple modeling is put forward based on the spiral motion of the workpiece as an essential characteristic in movement. The influence of the feed angle and the entry cone angle of the main roll on the process was taken into account in the modeling. The soundness for simplifying the 3-D rotary rolling into a 2-D problem was discussed. By adopting the parameters of Diescher piercer in 140mm mandrel mill of Bao Steel, the distribution and development of strain/stress were analyzed, and the eigen value of ductile fracture as well. The critical percentage of diameter reduction was obtained from the simulation. The result showed a good agreement with the experimental value, and therefore was of widely guiding significance to the practical process for rationally formulating the deformation parameters of steel tube piercing.


    Dmitrenko D. V.


    Full Text Available The article is dedicated to the determination of conditions for solid bodies’ fragmentation, providing minimal size of particles by means of their mechanical dispersion through the example of powders of titanium carbide (TiC, cubic boron nitride – borazon (CBN and boron carbide (B4C. The theoretical and practical aspects of the process of mechanical fragmentation of particles of solid powder materials in ball mill for their further utilization in furnace charge for high-speed gas-flame sputtering of wear-resistant composite materials are examined in the article. Methods of preliminary calculation of minimum allowable size of solid particles of powder materials during mechanical fragmentation, based upon Griffiths’ mechanical theory of rapture using experimental data for hardness of material and its yield are proposed and theoretically substantiated. There we have the results of experiments on mechanical fragmentation of titanium carbide in attritor, boron carbide and cubic boron nitride in centrifugal planetary mill, confirming correctness of theoretical propositions and calculations are set out. Recommendations on mechanical fragmentation of solid powder materials in ball mills are formulated as well


    Antonio Augusto Gorni; Marcos Roberto Soares da Silva


    An evaluation is made about the precision of hot strip rolling mill loads at the F1 stand calculated according to the theoretical models of Orowan, Sims, Alexander-Ford, Orowan-Pascoe, Ekelund and Tselikov in comparison to real values got for carbon-manganese steels. In the deterministic approach, without any fit of the calculated values to real data, Orowan, Sims and Alexander-Models show best levels of precision, as expected from the information got in the literature. However, i...

  4. Long-and Short-Term Self-Learning Models of Rolling Force in Rolling Process Without Gaugemeter of Plate

    ZHU Fu-wen; ZENG Qing-liang; HU Xian-lei; LI Xi-an; LIU Xiang-hua


    .Owing to a lack of gaugemeter and the variety of steel grades and standards in some plate mills,the longand short-term self-learning models of rolling force based on gauge soft-measuring with high precision were brought up.The soft-measuring method and target value locked method were used in these models to confirm the actual exit gauge of passes,and thick layer division and exponential smoothing method were used to dispose the deformation resistance parameter,which could be calculated from the actual data of the rolling process.The correlative mathematical methods can also be adapted to self-learning with gaugemeter.The models were applied to the process control system of AGC (automatic gauge control) reconstruction on 2 800 mm finishing mill of Anyang steel and favorable effect was obtained.

  5. Rolling Regressions with Stata

    Kit Baum


    This talk will describe some work underway to add a "rolling regression" capability to Stata's suite of time series features. Although commands such as "statsby" permit analysis of non-overlapping subsamples in the time domain, they are not suited to the analysis of overlapping (e.g. "moving window") samples. Both moving-window and widening-window techniques are often used to judge the stability of time series regression relationships. We will present an implementation of a rolling regression...

  6. Rolling resistance of tires

    Junio, M.; Roesgen, A.; Corvasce, F. [Goodyear Technical Center Luxembourg, Colmar-Berg (Luxembourg)


    After a review of the contribution of tire rolling resistance to fuel economy, the tire rolling resistance is defined and measurement methods discussed. The significant effects of the 'external' factors such as load, inflation, temperature, speed, etc. that are not controlled by the tire developers, are reviewed. Tire construction changes that reduce deformations and compound changes reducing hysteresis are discussed and information is provided on what has been achieved so far and what might be done in the future. (orig.)

  7. Innovative grinding wheel design for cost-effective machining of advanced ceramics

    Licht, R.H.; Kuo, P.; Liu, S.; Murphy, D.; Picone, J.W.; Ramanath, S.


    This Final Report covers the Phase II Innovative Grinding Wheel (IGW) program in which Norton Company successfully developed a novel grinding wheel for cost-effective cylindrical grinding of advanced ceramics. In 1995, Norton Company successfully completed the 16-month Phase I technical effort to define requirements, design, develop, and evaluate a next-generation grinding wheel for cost-effective cylindrical grinding of advanced ceramics using small prototype wheels. The Phase II program was initiated to scale-up the new superabrasive wheel specification to larger diameters, 305-mm to 406-mm, required for most production grinding of cylindrical ceramic parts, and to perform in-house and independent validation grinding tests.


    Vladmir Kronemberger Alves


    Full Text Available Over the years Vale S.A. has developed a methodology for scaling industrial comminution circuit that is being constantly improved and implemented in developing new routes and process optimization of circuits in operation. This work will be given a focus on the methodology of simplified balls mill Work Index (WI Anaconda in performance prediction of Sossego Plant ball mill. The great advantage of this methodology is to reduce the time and weight to determine the energy consumption in ball mills, whose values can be used in studies of variability, geometallurgy and design and control of industrial grinding circuits.

  9. The Design of Form Milling Cutter as the Curve of the Back of Tooth Is Logarithmic Spiral


    Form milling cutter is built-for-purpose cutter which process the form surface, for example, usually process male and female circular arc face and form trench and so on. From the traditional concept, form milling cutter is divided into pointed tooth and relieving follow its structure. Relieving shaped cutter is more convenient than pointed tooth milling cutter, because only its rake face is needed to grind after it turn into blunting, so the current books which are used in college almost select relieving ...

  10. Ball-milled sulfur-doped graphene materials contain metallic impurities originating from ball-milling apparatus: their influence on the catalytic properties.

    Chua, Chun Kiang; Sofer, Zdeněk; Khezri, Bahareh; Webster, Richard D; Pumera, Martin


    Graphene materials have found applications in a wide range of devices over the past decade. In order to meet the demand for graphene materials, various synthesis methods are constantly being improved or invented. Ball-milling of graphite to obtain graphene materials is one of the many versatile methods to easily obtain bulk quantities. In this work, we show that the graphene materials produced by ball-milling are spontaneously contaminated with metallic impurities originating from the grinding bowls and balls. Ball-milled sulfur-doped graphene materials obtained from two types of ball-milling apparatus, specifically made up of stainless steel and zirconium dioxide, were investigated. Zirconium dioxide-based ball-milled sulfur-doped graphene materials contain a drastically lower amount of metallic impurities than stainless steel-based ball-milled sulfur-doped graphene materials. The presence of metallic impurities is demonstrated by their catalytic effects toward the electrochemical catalysis of hydrazine and cumene hydroperoxide. The general impression toward ball-milling of graphite as a versatile method for the bulk production of 'metal-free' graphene materials without the need for post-processing and the selection of ball-milling tools should be cautioned. These findings would have wide-reaching implications for graphene research.

  11. Storsional self-excited vibration of rolling mill

    唐华平; 严珩志; 钟掘


    The roller's torsional self-excited vibration caused by roller stick-slip,and its influence on strip surface quality have been studied.Based on analysis of roller working surface stick-slip,roller rotation dynamics equations have been established.The nonlinear sliding-frictional resistance has been linearized,and dynamics equations have been solved according to the characteristics of stick and slip between roller and strip.The results show that: 1) with decreasing stick time t 1,torsional vibration wave pattern gradually transforms from serration into sinusoid,and frictional self-excited vibration can cover all frequency components which are lower than that of free vibration;2) stick time t 1 is directly proportional to torque increment Δ MR ,and is inversely proportional to live shaft stiffness K and drive shaft rotational velocity ω ;3) when slip time t 2 is basically steady,the longer the stick time,the larger the energy that system absorbs and discharges.As the slip time is a constant,it easily arouses strip surface shear impact and surface streaks.

  12. Laser-assisted Grinding Wheel Dressing (Ⅱ)-Experimental Researches

    Ming CHEN; Fanghong SUN; Youngmoon LEE; Seunghan YANG; Jongchan LEE


    Most of the mechanical dressing technologies for resin bonded superabrasive grinding wheels are time consumingand costly. Based on the outcomes of the simulations in the previous study, this paper demonstrates the comprehensive researches on the laser-ass

  13. Gemstone Grinding Process Improvement by using Impedance Force Control

    Hamprommarat Chumpol


    Full Text Available Chula Automatic Faceting Machine has been developed by The Advance Manufacturing Research Lab, Chulalongkorn University to support Thailand Gems-Industry. The machine has high precision motion control by using position and force control. A contact stiffness model is used to estimate grinding force. Although polished gems from the Faceting Machine have uniform size and acceptable shape, the force of the grinding and polishing process cannot be maintain constant and has some fluctuation due to indirect force control. Therefor this research work propose a new controller for this process based on an impedance direct force control to improve the gemstone grinding performance during polishing process. The grinding force can be measured through motor current. The results show that the polished gems by using impedance direct force control can maintain uniform size as well as good shape and high quality surface.

  14. A critical study of high efficiency deep grinding

    Johnstone, I


    The recent years, the aerospace industry in particular has embraced and actively pursued the development of stronger high performance materials, namely nickel based superalloys and hardwearing steels. This has resulted in a need for a more efficient method of machining, and this need was answered with the advent of High Efficiency Deep Grinding (HEDG). This relatively new process using Cubic Boron Nitride (CBN) electroplated grinding wheels has been investigated through experimental and theoretical means applied to two widely used materials, M50 bearing steel and IN718 nickel based superalloy. It has been shown that this grinding method using a stiff grinding centre such as the Edgetek 5-axis machine is a viable process. Using a number of experimental designs, produced results which were analysed using a variety of methods including visual assessment, sub-surface microscopy and surface analysis using a Scanning Electron Microscope (SEM), residual stress measurement using X-Ray Diffraction (XRD) techniques, Ba...

  15. E-Records a Grind for Many Doctors

    ... page: E-Records a Grind for Many Doctors And this ... direct contact with patients and 37 percent on E-health records and other clerical work, the study ...

  16. Coiling Temperature Control in Hot Strip Mill

    Imanari, Hiroyuki; Fujiyama, Hiroaki

    Coiling temperature is one of the most significant factors in products of hot strip mill to determine material properties such as strength, toughness of steel, so it is very important to achieve accurate coiling temperature control (CTC). Usually there are a few pyrometers on the run out table in hot strip mill, therefore temperature model and its adapting system have large influences on the accuracy of CTC. Also unscheduled change of rolling speed has a bad effect to keep coiling temperature as its target. Newly developed CTC system is able to get very accurate coiling temperature against uncertain factors and disturbances by adopting easily identified temperature model, learning method and dynamic set up function. The features of the CTC system are discussed with actual data, and the effectiveness of the system is shown by actual control results.

  17. 75 FR 71463 - Woodland Mills Corporation Mill Spring, NC; Notice of Revised Determination on Reconsideration


    ... Employment and Training Administration Woodland Mills Corporation Mill Spring, NC; Notice of Revised... of Woodland Mills Corporation, Mill Spring, North Carolina, to apply for Trade Adjustment Assistance... yarn produced by Woodland Mills Corporation, Mill Spring, North Carolina Woodland Mills...

  18. 磨矿方法对某硫化矿浮选的影响%Effects of Grinding Measure on Complex Pb/Zn Ore Flotation

    魏以和; 周高云


    The flotation performances of a complex Pb/zn ore are investigated by three kinds of mill(steel,stainless and ceramic mill)in laboratory batch flotation testa.It is found that the lead recovery is increased while grinding in a ceramic mill,i.e.a non-ferrous,oxidizing environment.but the selectivity is decreased due to the activation ol sphalerite by copper ions produced via the oxidation of ore.On the contrary,the lead recovery is decreased while grinding in a traditionel iron mill,but the selectivity is increased.The low recovery with iron grinding media is probably caused by the coating of iron oxy-hydroxides on sulphide surfaces.Coarse particles are more sensitive to this kind of depression.%为提高效果,用三种磨机(普通钢磨机,不锈钢磨机和瓷磨机)研究某铅锌矿小型试验的浮选行为.结果表明,瓷磨机(即非铁质磨机)的氧化性磨矿环境可提高铅回收率,但由于矿石氧化产生的铜离子对闪锌矿的活化而降低了浮选选择性.相反地,传统铁质磨机磨矿则导致铅收率下降,而选择性提高.铁质磨机磨矿时铅收率降低可能是由铁氧化产物在矿物表面覆盖而造成的.粗粒更易受这种抑制的影响.

  19. A Path Planning Method for Robotic Belt Surface Grinding

    WANG Wei; YUN Chao


    The flexible contact and machining with wide strip are two prominent advantages for the robotic belt grinding system,which can be widely used to improve the surface quality and machining efficiency while finishing the workpieces with sculptured surfaces.There lacks research on grinding path planning with the constraint of curvature.With complicated contact between the contact wheel and the workpiece,the grinding paths for robot can be obtained by the theory of contact kinematics.The grinding process must satisfy the universal demands of the belt grinding technologies,and the most important thing is to make the contact wheel conform to the local geometrical features on the contact area.For the local surfaces with small curvature,the curve length between the neighboring cutting locations becomes longer to ensure processing efficiency.Otherwise,for the local areas with large curvature,the curve length becomes shorter to ensure machining accuracy.A series of planes are created to intersect with the target surface to be ground,and the corresponding sectional profile curves are obtained.For each curve,the curve length between the neighboring cutting points is optimized by inserting a cutter location at the local area with large curvatures.A method of generating the grinding paths including curve length spacing optimization is set up.The validity is completely approved by the off-line simulation,and during the grinding experiments with the method,the quality of surface is improved.The path planning method provides a theoretical support for the smooth and accuracy path of robotic surface grinding.

  20. Performance analysis of magnesium phosphate cement mortar containing grinding dust


    Magnesium phosphate cement materials are formed by reacting magnesium oxide with water-soluble phosphates such as monoammonium dihydrogen phosphate (ADP), which solidifies at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate cement were molded and varying amounts (0 to 30% weight) of grinding dust were added to the ceramic matrices. The influence of the addition of grinding dust on the characteristics of the mortars in t...

  1. Teeth Grinding: Is Emotional Stability related to Bruxism?

    Sutin, Angelina R; Terracciano, Antonio; Ferrucci, Luigi; Costa, Paul T.


    This study examines the association between personality traits and bruxism, the repetitive grinding or clenching of teeth. Community-dwelling participants (N = 470) had a comprehensive oral examination by a dentist and completed a dental history and personality questionnaires. Consistent with the literature on state anxiety and depression as antecedents of bruxism, Neuroticism-related traits were associated with self-reported teeth grinding. These traits were also associated with other oral c...

  2. Austempering of hot rolled transformation-induced plasticity steels

    Zhuang Li; Di Wu


    Thermomechanical controlled processing (TMCP) was conducted by using a laboratory hot rolling mill. Austempering inAustempering in the salt bath after hot rolling Was investigated. The effect of isothermal holding time on mechanical properties was studied throughing of the microstructure and mechanical properties of the specimens. The mechanism of transformation-induced plasticity (TRIP) was discussed. The results show that the microstructure of these steels consists of polygonal ferrite, granular bainite, and ad TRIP occur in the hot rolled Si-Mn TRIP steels. Excellent mechanical properties were obtained for various durations at 400℃. Prolonged holdingprecipitation, which destabilized the austenite. The mechanical properties were optimal when the specimen was held for 25 min, and the tensile strength, total elongation, and strength ductility balance reached the maximum values of 776 MPa, 33%,respevtively.

  3. Rolling Force and Rolling Moment in Spline Cold Rolling Using Slip-line Field Method

    ZHANG Dawei; LI Yongtang; FU Jianhua; ZHENG Quangang


    Rolling force and rolling moment are prime process parameter of external spline cold rolling. However, the precise theoretical formulae of rolling force and rolling moment are still very fewer, and the determination of them depends on experience. In the present study, the mathematical models of rolling force and rolling moment are established based on stress field theory of slip-line. And the isotropic hardening is used to improve the yield criterion. Based on MATLAB program language environment, calculation program is developed according to mathematical models established. The rolling force and rolling moment could be predicted quickly via the calculation program, and then the reliability of the models is validated by FEM. Within the range of module of spline m=0.5-1.5 mm, pressure angle of reference circle α=30.0°-45.0°, and number of spline teeth Z=19-54, the rolling force and rolling moment in rolling process (finishing rolling is excluded) are researched by means of virtualizing orthogonal experiment design. The results of the present study indicate that:the influences of module and number of spline teeth on the maximum rolling force and rolling moment in the process are remarkable;in the case of pressure angle of reference circle is little, module of spline is great, and number of spline teeth is little, the peak value of rolling force in rolling process may appear in the midst of the process;the peak value of rolling moment in rolling process appears in the midst of the process, and then oscillator weaken to a stable value. The results of the present study may provide guidelines for the determination of power of the motor and the design of hydraulic system of special machine, and provide basis for the farther researches on the precise forming process of external spline cold rolling.

  4. The use of Bayesian Networks in Detecting the States of Ventilation Mills in Power Plants

    Sanja Vujnović


    Full Text Available The main objective of this paper is to present a new method of predictive maintenance which can detect the states of coal grinding mills in thermal power plants using Bayesian networks. Several possible structures of Bayesian networks are proposed for solving this problem and one of them is implemented and tested on an actual system. This method uses acoustic signals and statistical signal pre-processing tools to compute the inputs of the Bayesian network. After that the network is trained and tested using signals measured in the vicinity of the mill in the period of 2 months. The goal of this algorithm is to increase the efficiency of the coal grinding process and reduce the maintenance cost by eliminating the unnecessary maintenance checks of the system.

  5. Effect of strain accumulation and dynamic re-crystallization on the flow stress of steels during flat rolling; Efeito da deformacao acumulada e da recristalizacao dinamica na resistencia a deformacao de acos alta resistencia baixa liga durante a laminacao de tiras a quente

    Sarmento, Eduardo C. [USIMINAS, Ipatinga, MG (Brazil). Centro de Pesquisas


    The flow stress during hot strip mill rolling of two C-Mn steels and three grades of Nb steel has been examined using industrial rolling data obtained from two different hot strip mills. (author). 5 refs., 12 figs., 4 tabs.

  6. Development and Performance Evaluation of Maize Threshing and Grinding Machine

    Ugwu K. C.


    Full Text Available The Maize threshing and grinding machine was designed, fabricated and its performance was evaluated. The machine consists of two compartments which include the threshing and grinding chamber. Threshing chamber is where the maize grain is been separated from the cob, and the cob will be collected through the outlet chute. Therefore, before the maize grain enters into the grinding chamber, blower will separate the grain from the chaff. The separated grain enters the grinding chamber and is being grounded by compressive means through the stationary disc and the grinding plate. A 2 hp electric motor provides drive through belt connections to drive the pulley on threshing chamber and another 2 hp electric motor provide drive for the grinding chamber. The actual test was conducted using three different moisture contents and feed rates. It was observed that the efficiency of the machine was hindered by high moisture content. The results obtained showed that the machine performed well at low moisture content. The efficiency of the machine was 99.01% on the moisture content of 10%. The analysis of variance (ANOVA of the results obtained at 5% percent probability confirmed that the moisture content of the maize was an important parameter that affects the performance of the machine

  7. Establishment of mathematical moment model in twin casting rolling rolls

    孙斌煜; 苑世剑; 张洪; 杜艳平; 张芳萍


    In continuous casting rolling process, the deformed body is different from the hot rolling strip. The metal in casting rolling zone is first assumed to be viscous fluid and the mathematical model of casting rolling force is established, then the calculating formula for casting rolling torque is derived. In addition, considering the effects of deforming cone and appendant torque of rotary junctions sealing ring, the calculating model which accords with casting rolling condition is found out. Theoretical formula is proved by experiment.

  8. Spray Rolling Aluminum Strip

    Lavernia, E.J.; Delplanque, J-P; McHugh, K.M.


    Spray forming is a competitive low-cost alternative to ingot metallurgy for manufacturing ferrous and non-ferrous alloy shapes. It produces materials with a reduced number of processing steps, while maintaining materials properties, with the possibility of near-net-shape manufacturing. However, there are several hurdles to large-scale commercial adoption of spray forming: 1) ensuring strip is consistently flat, 2) eliminating porosity, particularly at the deposit/substrate interface, and 3) improving material yield. Through this program, a new strip/sheet casting process, termed spray rolling, has been developed, which is an innovative manufacturing technique to produce aluminum net-shape products. Spray rolling combines the benefits of twin-roll casting and conventional spray forming, showing a promising potential to overcome the above hurdles associated with spray forming. Spray rolling requires less energy and generates less scrap than conventional processes and, consequently, enables the development of materials with lower environmental impacts in both processing and final products. Spray Rolling was developed as a collaborative project between the University of California-Davis, the Colorado School of Mines, the Idaho National Engineering and Environmental Laboratory, and an industry team. The following objectives of this project were achieved: (1) Demonstration of the feasibility of the spray rolling process at the bench-scale level and evaluation of the materials properties of spray rolled aluminum strip alloys; and (2) Demonstration of 2X scalability of the process and documentation of technical hurdles to further scale up and initiate technology transfer to industry for eventual commercialization of the process.

  9. Effect of Milling Time on Al-Fe-Cr-20 Wt. % Al2O3composite Prepared Through Ball Milling

    Hameedur Rehman Khan


    Full Text Available One of the main challenges towards achieving a homogeneous distribution of the ceramic phase in the metal matrix composites is agglomeration of the reinforcement particles. Mechanical alloying is among the most important processing techniques used for manufacturing of metal matrix composites (MMCs.An attempt was made to synthesize Al-Fe-Cr-Al2O3composites synthesized through mechanical alloying. Al2O3 is used as reinforcement. Ethanol (5 wt. % has been used as a process control agent (PCA. Mechanical alloying is carried out in a conventional ball mill using stainless steel grinding media at 115 rpm in the argon environment for 5h, 10h and 15h. The ball to powder weight ratio was maintained at 20:1. The characterization of the ball milled powder was followed by scanning electron microscopy (SEM. Showed the formation of a homogeneous phase for all compositions after milling for 15 h. XRD patterns were recorded for the milled powders, and analyzed using Williamson–Hall method and Scherrer’s equation to determine the lattice strain and grain size.EDX is performed to check the contamination of composites during the mechanical alloying.XRD is used to study structural evolution of synthesized aluminium composite. Effect of milling time is investigated on synthesized Al-Fe-Cr-20 wt. % Al2O3 composites.

  10. Micro-Plasto-Hydrodynamic Lubrication a Fundamental Mechanism in Cold Rolling

    Laugier, Maxime; Boman, Romain; Legrand, Nicolas


    This paper presents recent investigations in Micro-Plasto-Hydrodynamic (MPH) lubrication. Industrial evidences of the existence of MPH lubrication mechanism for cold rolling processes are presented. A new lubrication model developed for strip drawing processes is then applied to predict the MPH...... lubrication initiation and MPH lubrication extension along the tool-piece solid contacts initially in boundary lubrication regime. Finally, it is shown how this new MPH lubrication model can be implemented in a cold rolling model to maximize mills capabilities, determine optimum rolling oils properties...

  11. Effect of glucosamine HCl on dissolution and solid state behaviours of piroxicam upon milling.

    Al-Hamidi, Hiba; Edwards, Alison A; Douroumis, Dionysis; Asare-Addo, Kofi; Nayebi, Alireza Mohajjel; Reyhani-Rad, Siamak; Mahmoudi, Javad; Nokhodchi, Ali


    Piroxicam is a non-steroidal anti-inflammatory drug that is characterised by low solubility and high permeability. In order to improve the drug dissolution rate, the co-grinding method was used as an approach to prepare piroxicam co-ground in the carriers such as glucosamine hydrochloride. As, this amino sugar (glucosamine HCl) has been shown to decrease pain and improve mobility in osteoarthritis in joints, therefore, the incorporation of glucosamine in piroxicam formulations would be expected to offer additional benefits to patients. The effect of the order of grinding on the dissolution of piroxicam was also investigated. Co-ground drug and glucosamine were prepared in different ratios using a ball mill. The samples were then subjected to different grinding times. In order to investigate the effect of the grinding process on the dissolution behaviour of piroxicam, the drug was ground separately in the absence of glucosamine. Mixtures of ground piroxicam and unground D-glucosamine HCl were prepared. Physical mixtures of piroxicam and glucosamine were also prepared for comparison. The properties of prepared co-ground systems and physical mixtures were studied using a dissolution tester, FTIR, SEM, XRPD and DSC. These results showed that the presence of glucosamine HCl can increase dissolution rate of piroxicam compared to pure piroxicam. Generally, all dissolution profiles showed the fastest dissolution rate when ground piroxicam was mixed with unground glucosamine. This was closely followed by the co-grinding of piroxicam with glucosamine where lower grinding times showed the fastest dissolution. The solid state studies showed that the grinding of piroxicam for longer times had no effect on polymorphic form of piroxicam, whereas mixtures of piroxicam-glucosamine ground for longer times (60 min) converted piroxicam polymorph II to polymorph I.

  12. Multilayer Steel Materials Deformation Resistance and Roll Force Measurement

    A. G. Kolesnikov


    Full Text Available To create new types of cars, raise their reliability, gain operational life, and decrease in metal consumption of products it is necessary to improve mechanical, physical, and also special properties of the constructional materials applied in mechanical engineering. Presently, there are intensive researches and developments under way to create materials with ultrafine-grained structure (the sizes of grains in their crystal lattice make less than 1 micron in one of the measurements.BMSTU developed a manufacturing technology of multilayer steel sheets with steady ultrafine-grained structure based on the multiple hot rolling of billet as a composition consisting of the alternating metal sheets. A principled condition for implementation of such technology is existence of different crystallographic modifications in the adjoining sheets of the composition at specified temperature of rolling.Power parameters of rolling are important technical characteristics of the process. Usually, to determine a deformation resistance value when rolling the diverse multilayer materials, is used the actual resistance value averaging in relation to the components of the composition. The aim of this work is a comparative analysis of known calculated dependences with experimental data when rolling the 100-layer samples. Objects of research were the 100-layer compositions based on the alternating layers of steel 08H18N10 and U8.Experimental samples represented the vacuumized capsules with height, width, and length of 53 mm x 53 mm x 200 mm, respectively, in which there were the 100-layer packs from sheets, each of 0.5 mm, based on the composition of steels (U8+08H18N10. Rolling was made on the double-high mill with rolls of 160 mm in diameter during 19 passes to the thickness of 7 mm with the speed of 0,1 m/s. Relative sinking in each pass was accepted to be equal 10±2,5%. Rolling forces were measured by the strain-gauging method using the measuring cells, located under

  13. Effect of pass schedule and groove design on the metal deformation of 38MnVS6 in the initial passes of hot rolling

    R S Nalawade; V R Marje; G Balachandran; V Balasubramanian


    The deformation behaviour of a hot rolled micro-alloyed steel bar of grade 38MnVS6 was examined using an FEM model during the initial passes in a blooming mill, as a function of three different pass schedules,roll groove depth, collar taper angle and corner radius. The simulations predicted the effective strain penetration,load, torque, fish tail billet end shapes, and metal flow behaviour at a chosen temperature, mill rpm and draft. The model predictions were validated for typical groove geometry and a typical pass schedule. Lower collar taper angle, lower corner radius and higher depth of groove in hot rolling enabled achievement of higher strain penetration, higher mill load and lower fish tail formation. The present study establishes the capability of the model to improve the internal quality of the rolled billet as measured by effective strain which was corroborated to the rolled bar macrostructure and microstructure. The model enables yield improvement by the choice of draft to minimise fish tail losses. The surface quality is improved by the ability to avoid fin formation that occurs at certain conditions of rolling. Thus, the groove geometry, roll pass schedule and rolling mill parameters and temperature can be optimised for best product quality and yield.

  14. Global coupled equations for dynamic analysis of planishing mill

    蔡敢为; 钟掘


    The dynamic properties of rolling mill are significantly influenced by many coupling factors. Accordingto the coupled mechanical and electric dynamics theory, the global coupled equations for the dynamic analysis ofplanishing mill CM04 of Shanghai Baosteel Group Corporation were derived, by using finite element methods. Theseelasto-dynamic equations establish the coupling relations among the stand vibration system, torsional vibration sys-tem, driving motors, etc. It provides theoretical basis to a certain extent for globally dynamic simulation, analysis ofstability of motion, prediction of abnormal operating mode, globally optimum design and control, etc.

  15. Sliding and Rolling: The Physics of a Rolling Ball.

    Hierrezuelo, J.; Carnero, C.


    Presents an approach that provides a simple and adequate procedure for introducing the concept of rolling friction. Discusses some aspects related to rolling motion that are the source of students' misconceptions. Presents several didactic suggestions. (JRH)

  16. Ship Roll Damping Control

    Perez, Tristan; Blanke, Mogens


    The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of difficulties associated with control system designs, which have proven to be far from trivial due to fundamental performance...... limitations and large variations of the spectral characteristics of wave-induced roll motion. This tutorial paper presents an account of the development of various ship roll motion control systems together with the challenges associated with their design. It discusses the assessment of performance...... and the applicability of different mathematical models, and it surveys the control methods that have been implemented and validated with full scale experiments. The paper also presents an outlook on what are believed to be potential areas of research within this topic....

  17. Microstructural Characterization of Calcite-Based Powder Materials Prepared by Planetary Ball Milling

    Wen-Tien Tsai


    Full Text Available In this work, a planetary ball milling was used to modify the surface properties of calcite-based material from waste oyster shell under the rotational speed of 200–600 rpm, grinding time of 5–180 min and sample mass of 1–10 g. The milling significantly changed the microstructural properties of the calcite-based minerals (i.e., surface area, pore volume, true density, and porosity. The surface characterization of the resulting powder should be macroporous and/or nonporous based on the nitrogen adsorption/desorption isotherms. Under the optimal conditions at the rotational speed of 400 rpm, grinding time of 30 min and sample mass of 5 g, the resulting calcite-based powder had larger specific surface area (i.e., 10.64 m2·g−1 than the starting material (i.e., 4.05 m2·g−1. This finding was also consistent with the measurement of laser-diffraction (i.e., 9.7 vs. 15.0 μm of mean diameter. In addition, the results from the scanning electron microscope (SEM observation indicated that surface roughness can be enhanced as particle size decreases as a result of particle-particle attrition. Thus, grinding the aquacultural bioresource by a high-energy ball milling can create the fine materials, which may be applied in the fields of inorganic minerals like aggregate and construction material.

  18. Modeling, simulation and identification for control of tandem cold metal rolling

    Péricles Guedes Alves


    Full Text Available This paper describes a modeling procedure for tandem cold metal rolling, including the linearization step and system identification for control. The tandem cold rolling process is described by a mathematical model based on algebraic equations developed for control purposes and empirical relations. A state-space model is derived and detailed analyses in open loop are presented, concerning the sensitivity with regard to the variations in process parameters and results for the application of a new subspace identification method are compared with classical methodologies. Therefore, this work intents to be a contribution for developments in new control strategies for tandem cold rolling process that offer the potential to reduce the design efforts, the commissioning time and maintenance in rolling mills. The preliminary results obtained with this model have shown reasonable agreement with operational data presented at literature for industrial cold rolling process.

  19. Automatic flatness control strategy with a Smith predictor for steel strip rolling

    Zhang, Ruicheng; Zheng, Xin


    The simplified transfer function diagram block for a automatic flatness control (AFC) system of strip steel rolling process was investigated. For the problem of automatic flatness control (AFC) in cold tandem mills this paper proposes control techniques based on Smith predictor to compensate for the numerous delays present in the mill. After a Smith predictor was used to the AFC system, the control laws were deduced for both proportional and integral regulators. Control algorithms are tested in simulation considering a tandem mill with four stands as a benchmark, and results are shown to demonstrate the performance of the proposed schemes.

  20. Stochastic disks that roll

    Holmes-Cerfon, Miranda


    We study a model of rolling particles subject to stochastic fluctuations, which may be relevant in systems of nano- or microscale particles where rolling is an approximation for strong static friction. We consider the simplest possible nontrivial system: a linear polymer of three disks constrained to remain in contact and immersed in an equilibrium heat bath so the internal angle of the polymer changes due to stochastic fluctuations. We compare two cases: one where the disks can slide relative to each other and the other where they are constrained to roll, like gears. Starting from the Langevin equations with arbitrary linear velocity constraints, we use formal homogenization theory to derive the overdamped equations that describe the process in configuration space only. The resulting dynamics have the formal structure of a Brownian motion on a Riemannian or sub-Riemannian manifold, depending on if the velocity constraints are holonomic or nonholonomic. We use this to compute the trimer's equilibrium distribution with and without the rolling constraints. Surprisingly, the two distributions are different. We suggest two possible interpretations of this result: either (i) dry friction (or other dissipative, nonequilibrium forces) changes basic thermodynamic quantities like the free energy of a system, a statement that could be tested experimentally, or (ii) as a lesson in modeling rolling or friction more generally as a velocity constraint when stochastic fluctuations are present. In the latter case, we speculate there could be a "roughness" entropy whose inclusion as an effective force could compensate the constraint and preserve classical Boltzmann statistics. Regardless of the interpretation, our calculation shows the word "rolling" must be used with care when stochastic fluctuations are present.

  1. Research on Stability Prediction of the Crankshaft CNC Tangential Point Tracing Grinding

    Zhuoda Jiang


    Full Text Available As the key part of internal combustion engines, crankshaft with high efficiency and accuracy processing has always been the target of the engine manufacturer’s pursuit. Grinding is used to obtain the ultimate dimensional accuracy and surface finish in the crankshaft machining. Grinding of the main journals and the pin journals can be accomplished in a single clamping operation by CNC Tangential Point Tracing grinding technology. However, the chatter in the grinding process is harmful to the precision and surface quality. In this paper, stability lobe diagram is developed to predict the grinding chatter. First the dynamic model of Tangential Point Tracing grinding system is established. Then the limit formula of the critical grinding depth is calculated and the stability lobe diagram of the grinding system is presented. Finally, the validation experiments are carried out on the crankshaft grinding machine and the results are consistent with the calculation.

  2. Geometrical principium of fewer-axis grinding for large complex optical mirrors

    JIANG; ZhenHua; YIN; YueHong


    Ultraprecision grinding is an important approach to efficiently fabricate large complex optical mirrors, and five-axis grinding method is commonly used for ultraprecision grinding. However, this method can hardly meet the high stiffness requirement for grinding large mirror, especially with a diameter over 2 m. Meanwhile, the use of fewer-axis grinding solves this problem, as it reduces the number of the grinder’s axes to improve the rigidity of the system and minimize deformation for hard and brittle materials. But its characteristic of unfixed grinding point which changes with workpiece surface curvature increases geometric complexity and requires a higher geometric shape accuracy of grinding wheel. This paper parameterizes grinding wheel’s geometric shape, reveals the relationship between fewer-axis and five-axis grinding methods from the point of view of the differential geometry, and establishes virtual-axis equivalence principium of feweraxis grinding. A quantitative method to determine grinding wheel’s geometric parameters and its shaft inclination angle is proposed based on the requirements of geometric properties of optical mirror, grinder features and grinding process. Moreover, according to the properties of Gauss curvature of curved surface, the wear law of the toric grinding wheel is found and the surface geometric error distribution due to wear is achieved for fewer-axis grinding. The correctness of the principium and method above are verified through simulations.

  3. Performance of Cooled Cone Grinding Machine in Cocoa Cake Processing

    Hendy Firmanto


    Full Text Available The process of cocoa paste pressing has a function to separate the fatty component of cocoa from its cake. Cocoa paste is further processed into cocoa powder using grinding machine for cocoa cake. The cooled cone type of cocoa grinding machine is used to solve the problem of plug in the maschine caused by melting of fat in cocoa cake due to hot effect as a result of friction in the grinding machine. Grinding machine of cocoa has conical form of cylinder for grinding and stator wall wrapped by source of cold and closed with jacket wool. Research was conducted at Kaliwining Experimental Garden of Indonesian Coffee and Cocoa Research Institute (ICCRI using cocoa cake containing 26.75% originated from Forastero type of cocoa seed. The capacity and recovery of the machine was influenced by space between rotor cylinder and stator wall. Grinding machine operated at cooling temperature of 25.5oC and space between rotor – stator 0.9 cm and the capacity of 187.5 kg/hour with recovery of 200 mesh cocoa powder as much as 24%. The maximum  power of machine required  was 2.5 kW with efficiency of  energy transfer of 97%. Results of proximate analysis showed that there was no change of protein content, but protein and carbohydrate content increased after processing, i.e. from 5.70% and 59.82% into 5.80% and 61.89% respectively.Key words : cocoa cake, cooling, grinding, cocoa powder 


    Smith, C.S.


    A method is described for rolling uranium metal at relatively low temperatures and under non-oxidizing conditions. The method involves the steps of heating the uranium to 200 deg C in an oil bath, withdrawing the uranium and permitting the oil to drain so that only a thin protective coating remains and rolling the oil coated uranium at a temperature of 200 deg C to give about a 15% reduction in thickness at each pass. The operation may be repeated to accomplish about a 90% reduction without edge cracking, checking or any appreciable increase in brittleness.

  5. Ship Roll Motion Control

    Perez, Tristan; Blanke, Mogens


    The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of deciencies in control system designs, which have proven to be far from trivial due to fundamental performance limitations....... This tutorial paper presents an account of the development of various ship roll motion control systems and the challenges associated with their design. The paper discusses how to assess performance, the applicability of dierent models, and control methods that have been applied in the past....

  6. Offensive Rolling in Sambo

    Stephen Koepfer


    Full Text Available In recent years the Soviet born martial art of sambo has become increasingly well known in martial art circles. This is largely due to the success of sambo fighters in various mixed martial art venues. Offered here is a brief description of sambo’s development as well as a delineation of one of sambo’s hallmark strategies: offensive rolling. Examples of proper forward rolling and three related offensive techniques are presented. This paper provides a brief introduction to sambo’s history and one of its key tactical philosophies.

  7. Quenching simulation of steel grinding balls

    Zapata-Hernández, Oscar


    Full Text Available The phase transformations of high carbon steel during quenching and equalizing were modelled using commercial computer packages based on the finite element method and the kinetic transformation of steel. The model was used to predict the temperature and microstructural changes taking place within balls of two different sizes that are used for grinding mineral ores. A good correlation between the temperatures measured by inserted thermocouples and those predicted by the model was obtained after modifying the thermal conductivity of the steel within the temperature domain at which mixed phases are present. The phase transformations predicted were confirmed by metallographic analyses.Las transformaciones de fase en aceros de alto carbono durante su temple y un posterior periodo de estabilización fueron modelizadas por medio del uso de paquetes computacionales basados en el método del elemento finito y de la transformación cinética de los aceros. El modelo se usó para predecir los cambios de temperatura y microestructura que se presentan en bolas de dos diferentes tamaños empleadas en estaciones de molienda de minerales. Se encontró una buena correlación entre las temperaturas medidas mediante la inserción de termopares y aquellas predichas por el modelo una vez que se modificó la conductividad térmica del acero en el intervalo mixto de fases. La predicción de las transformaciones de fase se confirmó a través del análisis metalográfico.

  8. Revitalizing America's Mills: A Report on Brownfields Mill Projects

    This report focuses on mills -- former textile, wood, paper, iron, and steel mills. The report describes the challenges and opportunities of mill sites with case studies highlighting some of the most creative solutions from across the country.

  9. Microstructure and properties of hot roll bonding layer of dissimilar metals. 2. Bonding interface microstructure of Zr/stainless steel by hot roll bonding and its controlling

    Yasuyama, Masanori; Ogawa, Kazuhiro; Taka, Takao; Nakasuji, Kazuyuki [Sumitomo Metal Industries Ltd., Osaka (Japan); Nakao, Yoshikuni; Nishimoto, Kazutoshi


    The hot roll bonding of zirconium and stainless steel inserted with tantalium was investigated using the newly developed rolling mill. The effect of hot rolling temperatures of zirconium/stainless steel joints on bonding interface structure was evaluated. Intermetallic compound layer containing cracks was observed at the bonding interface between stainless steel and tantalium when the rolling temperature was above 1373K. The hardness of the bonding layer of zirconium and tantalium bonded above 1273K was higher than tantalium or zirconium base metal in spite of absence of intermetallic compound. The growth of reaction layer at the stainless steel and tantalium interface and at the tantalium and zirconium interface was conforming a parabolic low when that was isothermally heated after hot roll bonding, and the growth rate was almost same as that of static diffusion bonding without using hot roll bonding process. It is estimated that the strain caused by hot roll bonding gives no effect on the growth of reaction layer. It was confirmed that the dissimilar joint of zirconium and stainless steel with insert of tantalium having the sound bonding interface were obtained at the suitable bonding temperature of 1173K by the usage of the newly developed hot roll bonding process. (author)

  10. Numerical modelling of the forging process of rolls for rolling mills

    Charles, J F; Castagne, S.; Zhang, Lihong; Habraken, Anne; Cescotto, Serge


    This article presents comparisons of forging processes between two flat tools, between two round tools, and at different forging temperatures. Simulation results help to recover and better understa,d long practice in the forging industry. Peer reviewed

  11. Ductile streaks in precision grinding of hard and brittle materials

    V C Venkatesh; S Izman; S Sharif; T T Mon; M Konneh


    Ductile streaks produced during diamond grinding of hard and brittle materials have aided the subsequent process of polishing. Two novel techniques were used to study the formation of ductile mode streaks during diamond grinding (primary process) of germanium, silicon, and glass. In the first technique, aspheric surfaces were generated on Ge and Si at conventional speeds (5000 rpm). In the second technique, diamond grinding of plano surfaces on glass and Si surfaces using high speed (100,000 rpm) was carried out. Form accuracy, surface finish and ductile mode grinding streaks are discussed in this paper. It was found that resinoid diamond wheels gave more ductile streaks than metal-bonded wheels but better form accuracy was obtained with the latter. Ductile streaks were obtained more easily with pyrex rather than with BK 7 glass thus necessitating very little time for polishing. Ductile streaks appeared in abundance on germanium rather than silicon. Both the novel grinding techniques were used on CNC machining centres.

  12. The Effect of Rolling As-Cast and Homogenized U-10Mo Samples on the Microstructure Development and Recovery Curves

    Joshi, Vineet V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Paxton, Dean M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burkes, Douglas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    Over the past several years Pacific Northwest National Laboratory (PNNL) has been actively involved in supporting the U.S. Department of Energy National Nuclear Security Administration Office of Material Management and Minimization (formerly Global Threat Reduction Initiative). The U.S. High- Power Research Reactor (USHPRR) project is developing alternatives to existing highly enriched uranium alloy fuel to reduce the proliferation threat. One option for a high-density metal fuel is uranium alloyed with 10 wt% molybdenum (U-10Mo). Forming the U-10Mo fuel plates/foils via rolling is an effective technique and is actively being pursued as part of the baseline manufacturing process. The processing of these fuel plates requires systematic investigation/understanding of the pre- and post-rolling microstructure, end-state mechanical properties, residual stresses, and defects, their effect on the mill during processing, and eventually, their in-reactor performance. In the work documented herein, studies were conducted to determine the effect of cold and hot rolling the as-cast and homogenized U-10Mo on its microstructure and hardness. The samples were homogenized at 900°C for 48 h, then later annealed for several durations and temperatures to investigate the effect on the material’s microstructure and hardness. The rolling of the as-cast plate, both hot and cold, was observed to form a molybdenum-rich and -lean banded structure. The cold rolling was ineffective, and in some cases exacerbated the as-cast defects. The grains elongated along the rolling direction and formed a pancake shape, while the carbides fractured perpendicularly to the rolling direction and left porosity between fractured particles of UC. The subsequent annealing of these samples at sub-eutectoid temperatures led to rapid precipitation of the ' lamellar phase, mainly in the molybdenum-lean regions. Annealing the samples above the eutectoid temperature did not refine the grain size or the banded

  13. High-speed, low-damage grinding of advanced ceramics Phase 1. Final report

    Kovach, J.A. [Eaton Corp., Willoughby Hills, OH (United States). Mfg. Technologies Center; Malkin, S. [Univ. of Massachusetts (United States)


    In manufacture of structural ceramic components, grinding costs can comprise up to 80% of the entire manufacturing cost. Most of these costs arise from the conventional multi-step grinding process with numerous grinding wheels and additional capital equipment, perishable dressing tools, and labor. In an attempt to reduce structural ceramic grinding costs, a feasibility investigation was undertaken to develop a single step, roughing-finishing process suitable for producing high-quality silicon nitride ceramic parts at high material removal rates at lower cost than traditional, multi-stage grinding. This feasibility study employed combined use of laboratory grinding tests, mathematical grinding models, and characterization of resultant material surface condition. More specifically, this Phase 1 final report provides a technical overview of High-Speed, Low-Damage (HSLD) ceramic grinding and the conditions necessary to achieve the small grain depths of cut necessary for low damage grinding while operating at relatively high material removal rates. Particular issues addressed include determining effects of wheel speed and material removal rate on resulting mode of material removal (ductile or brittle fracture), limiting grinding forces, calculation of approximate grinding zone temperatures developed during HSLD grinding, and developing the experimental systems necessary for determining HSLD grinding energy partition relationships. In addition, practical considerations for production utilization of the HSLD process are also discussed.

  14. Design and experimental study of a micro-groove grinding wheel with spray cooling effect

    Shi Chaofeng


    Full Text Available The effectiveness of grinding fluid supply has a crucial impact on grinding quality and efficiency in high speed grinding. In order to improve the cooling and lubrication, through in-depth research of self-inhaling internal cooling method and intermittent grinding mechanism, a new spray cooling method used in high speed grinding is proposed. By referring to the structure of bowl-shaped dispersion disk, the grinding wheel matrix with atomization ability is designed; through studying heat transfer of droplet collision and the influence of micro-groove on the boiling heat transfer, grinding segment with micro-groove is designed to enhance the heat flux of coolant and achieve maximum heat transfer between droplets and grinding contact zone. High-speed grinding experiments on GH4169 with the developed grinding wheel are carried out. The results show that with the micro-groove grinding wheel just 5.4% of pump outlet flow rate and 0.5% of spindle energy is needed to reduce the grinding temperature to 200 °C, which means the developed grinding wheel makes cooling high efficient and low energy consuming.

  15. Shape-Grinding by Direct Position/Force Control

    Chen, Guanghua; Xu, Weiwei; Minami, Mamoru

    Based on the analysis of the interaction between a manipulator's hand and a working object, a model representing the constrained dynamics of the robot is first discussed. The constrained forces are expressed by an algebraic function of states, input generalized forces, and the constraint condition, and then a direct position/force controller without force sensor is proposed based on the algebraic relation. To give a grinding system the ability to adapt to any object shape being changed by the grinding, we add a function estimating the constraint condition in real time for the adaptive position/force control. Evaluations through simulations, by fitting the changing constraint surface with spline functions, indicate that reliable position/force control and shape-grinding can be achieved by the proposed controller.


    A. Feskova


    Full Text Available Summary. The optimal parameters of milling and fractionation of flaxseeds were substantiated. It was found that the hull fraction with the highest content of lignan secoisolariciresinol diglucoside SDG was obtained when flaxseeds were grinded using a rotatory impact continuous operation mill at the rotation 1380-1640 rpm. Studies have shown that with the increasing of the rotor speed the number of unbriken seeds decreased. However, due to the fact that the shells are crushed more, they become more difficult to separate from the cotyledons. For identification and quantification of SDG the HPLC-MS method was used. It is found that the optimum separation membranes and cotyledon fraction occurs at sifting milled seeds sequentially through the sieves having meshes of 1 and 0.5 mm. The technology of industrial production of lignans-containing fraction and flour on the basis of flaxseeds processing were proposed. This technology includes milling flaxseeds at the rotation 1380-1640 rpm, with subsequent 2% silicon dioxide addition and stepwise sieving using sieves with the mesh size 2 mm. To use a fraction membranes high in lignans as raw material for biologically active additives to food it needed additional enforcement-ground to a size not more than 0.4 mm (technological features of capsulation. The developed technology allowed getting with maximum yields of lignans-containing fraction (10% yield and flaxseed flour (80% yield.

  17. Research on automatic loading & unloading technology for vertical hot ring rolling process

    Xiaokai Wang


    Full Text Available The automatic loading & unloading technology is the key to the automatic ring production line. In this paper, the automatic vertical hot ring rolling (VHRR process is taken as the target, the method of the loading & unloading for VHRR is proposed, and the mechanical structure of loading & unloading system is designed, The virtual prototype model of VHRR mill and loading & unloading mechanism is established, and the coordinated control method of VHRR mill and loading & unloading auxiliaries is studied, the movement trace and dynamic characteristic of the critical components are obtained. Finally, a series of hot ring rolling tests are conducted on the VHRR mill, and the production rhythm and the formed rings' geometric precision are analysed. The tests results show that the loading & unloading technology can meet the high quality and high efficiency ring production requirement. The research conclusions have practical significance for the large-scale automatic ring production.


    Zhao Henghua; Cai Guangqi; Jin Tan


    A new thermal model with triangular heat flux distribution is given in high-efficiency deep grinding. The mathematical expressions are driven to calculate the surface temperature. The transient behavior of the maximum temperature on contact area is investigated in different grinding conditions with a J-type thermocouple. The maximum contact temperatures measured in different conditions are found to be between 1 000 ℃ and 1 500 ℃ in burn-out conditions. The experiment results show good agreement with the new thermal model.

  19. Robotic Instrument for Grinding Rocks Into Thin Sections (GRITS)

    Paulsen, Gale; Zacny, Kris; Dreyer, Christopher B.; Szucs, Attila; Szczesiak, Matt; Santoro, Chris; Craft, Jack; Hedlund, Magnus; Skok, John


    We have developed a rock grinding and polishing mechanism for in situ planetary exploration based on abrasive disks, called Grinding Rocks Into Thin Sections (GRITS). Performance characteristics and design considerations of GRITS are presented. GRITS was developed as part of a broader effort to develop an in situ automated rock thin section (ISARTS) instrument. The objective of IS-ARTS was to develop an instrument capable of producing petrographic rock thin sections on a planetary science spacecraft. GRITS may also be useful to other planetary science missions with in situ instruments in which rock surface preparation are necessary.

  20. Performance analysis of magnesium phosphate cement mortar containing grinding dust

    Daniel Véras Ribeiro


    Full Text Available Magnesium phosphate cement materials are formed by reacting magnesium oxide with water-soluble phosphates such as monoammonium dihydrogen phosphate (ADP, which solidifies at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate cement were molded and varying amounts (0 to 30% weight of grinding dust were added to the ceramic matrices. The influence of the addition of grinding dust on the characteristics of the mortars in terms of microstructure (SEM, mechanical strength and capillary water absorption was verified. The results obtained proved very satisfactory for the use of this waste as an additive in magnesium phosphate mortars.

  1. Unusual orbitocranial penetrating injury by a grinding wheel: case report

    Murat Vural; Yakup Karabagli; Hikmet Basmak; Baki Adapinar; Ramazan Durmaz; Metin Ant Atasoy


    @@ Orbitocranial penetrating injuries are uncommon and usually life threatening, which constitute about 0.4% of all head injuries, 24% of penetrating head trauma in adults, and 45% in children.1,2,3They may occur accidentally or due to an assault and may have serious consequences and can be potentially fatal.4,5 Immediate plastic and reconstructive surgery, ophthalmology and radiology consultations are essential for the proper diagnosis and treatment. We reported an adult patient with a transorbital cerebral injury by an unusual material---grinding wheel. To our knowledge, this is the first reported case of transorbital penetrating injury by a grinding wheel in the literature.

  2. Effects of the grinding process on the preparation and qualities of CWS

    Yuliang Zhang; Guoguang Wu; Xianliang Meng; Zengjie Yun; Frank Shi; Yaqun He; Xiaoqiang Luo


    Two different grinding processes were examined to determine the effect grinding has on the quality of a CWS.A series of slurries was prepared from Australian (Au) and Chinese (YZ) coals.Both types of coal were ground by a Chinese (CUMT) and an Australian (JK) grinding process.The performance tests of the prepared CWS showed that fluidity of all slurries was acceptable.The concentration of the CWS from YZ coal ground by the CUMT grinding process was higher than when the JK grinding process was used.The highest concentration was 70.14% in this case.The concentration of the CWS prepared from Au coal by the JK grinding process was higher than when the CUMT grinding process was used.The highest concentration in this case was 70.97%.These differences are caused by the particle size distribution developed during the different grinding processes.


    N. V. Spiridonov; I. O. Sokorov; M. V. Niaroda


    The paper reveals thermal zones of magnetic and electric grinding process. The influence of electric and physical parameters of magnetic and electric grinding on temperature in the zone of gas and thermal protective coatings has been established in the paper.

  4. Effect of Grinding Process Parameters on Surface Area Roughness of Glass fibre Reinforced Composite Laminate under Dry and Coolant Environment

    P. Chockalingam


    Full Text Available This paper presents a comparative study on dry and wet grinding of chopped strand mat glass fibre reinforced polymer laminates using an alumina wheel. Investigations were performed to study the impact of the grinding parameters, namely feed, speed, and depth of cut on grinding force ratio and surface area roughness. Effective grinding parameters were sought in this study to maximize grinding force ratio and minimize surface area roughness. Test results show that coolant helped to decrease surface area roughness, but inevitably reduced the grinding force ratio in some cases. These findings lead to economic machining solution for optimum grinding conditions in grinding composite laminates.

  5. Optimal Cluster Mill Pass Scheduling With an Accurate and Rapid New Strip Crown Model

    Malik, Arif S.; Grandhi, Ramana V.; Zipf, Mark E.


    Besides the requirement to roll coiled sheet at high levels of productivity, the optimal pass scheduling of cluster-type reversing cold mills presents the added challenge of assigning mill parameters that facilitate the best possible strip flatness. The pressures of intense global competition, and the requirements for increasingly thinner, higher quality specialty sheet products that are more difficult to roll, continue to force metal producers to commission innovative flatness-control technologies. This means that during the on-line computerized set-up of rolling mills, the mathematical model should not only determine the minimum total number of passes and maximum rolling speed, it should simultaneously optimize the pass-schedule so that desired flatness is assured, either by manual or automated means. In many cases today, however, on-line prediction of strip crown and corresponding flatness for the complex cluster-type rolling mills is typically addressed either by trial and error, by approximate deflection models for equivalent vertical roll-stacks, or by non-physical pattern recognition style models. The abundance of the aforementioned methods is largely due to the complexity of cluster-type mill configurations and the lack of deflection models with sufficient accuracy and speed for on-line use. Without adequate assignment of the pass-schedule set-up parameters, it may be difficult or impossible to achieve the required strip flatness. In this paper, we demonstrate optimization of cluster mill pass-schedules using a new accurate and rapid strip crown model. This pass-schedule optimization includes computations of the predicted strip thickness profile to validate mathematical constraints. In contrast to many of the existing methods for on-line prediction of strip crown and flatness on cluster mills, the demonstrated method requires minimal prior tuning and no extensive training with collected mill data. To rapidly and accurately solve the multi-contact problem

  6. 热轧板凸度控制实践分析%Analysis about Crown Control of Hot Rolled Plate

    曾尚武; 李激光


    To the problem of hot rolled plate crown control, the influence of rolling load, bending force, roll thermal expansion, roll crown, roll wear, strip edge drop and wedge on plate crown were researched. The results show that the plate crown is deduced by the load of F3, F6 mill, the roll crown, the edge drop, the wedge absolute value decreasing and the load of F2 , F4, F5 mill, the bending force increasing. The roll thermal crown was formed within 30min. The plate crown was affected by roll uneven wear.%针对热轧板凸度控制问题,研究了轧制负荷、弯辊力、轧辊热膨胀、原始辊凸度、轧辊磨损、边缘降及楔形对板凸度的影响.结果表明,F3、F6机架负荷减小、F2、F4与F5机架负荷增大、弯凸度力增大、辊凸度减小、边缘降减小及楔形绝对值减小均可使带钢板凸度减小,轧辊热凸度约30min基本形成,轧辊不均匀磨损直接影响带钢板凸度.

  7. Obtention of hydroxyapatite submicrometric of bovine origin by vibratory grinding for rapid prototyping; Obtencao de hidroxiapatita submicrometrica de origem bovina por moagem vibratoria visando prototipagem rapida

    Meira, C.R.; Purquerio, B.M.; Fortulan, C.A., E-mail: [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Escola de Engenharia; Braga, F.J.C. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)


    Submicron bovine hydroxyapatite was obtained for rapid prototyping. Hydroxyapatite structure originated from bovine mineral bone has great importance among the biomaterials and biocompatibility due to its great similarity with the human bone structure. This study aims to obtain powder for manufacture by rapid prototyping of scaffolds. This technique manufacture requires highly reactive powders to compensate for the absence of pressure forming. Hydroxyapatite was milled in a ball mill and vibratory mill, and analyzed for their average equivalent spherical diameter and surface area. Test specimens were isostatically pressed at 100 MPa and machined into cylindrical test specimens. These specimens were sintered at several temperatures to determine the optimal sintering temperature based on densification and chemistry stability. In grinding ball mill was obtained particles of equivalent diameter of 0.74 micron in vibratory mill of 0.46 micrometers. An average flexural strength of 100 MPa and 99,8% of real density was attained for the sample sintered at 1300 deg C/2h, signaling potential for use in rapid prototyping. (author)

  8. Study on Effect of Ultrasonic Vibration on Grinding Force and Surface Quality in Ultrasonic Assisted Micro End Grinding of Silica Glass

    Zhang Jianhua


    Full Text Available Ultrasonic vibration assisted micro end grinding (UAMEG is a promising processing method for micro parts made of hard and brittle materials. First, the influence of ultrasonic assistance on the mechanism of this processing technology is theoretically analyzed. Then, in order to reveal the effects of ultrasonic vibration and grinding parameters on grinding forces and surface quality, contrast grinding tests of silica glass with and without ultrasonic assistance using micro radial electroplated diamond wheel are conducted. The grinding forces are measured using a three-component dynamometer. The surface characteristics are detected using the scanning electron microscope. The experiment results demonstrate that grinding forces are significantly reduced by introducing ultrasonic vibration into conventional micro end grinding (CMEG of silica glass; ultrasonic assistance causes inhibiting effect on variation percentages of tangential grinding force with grinding parameters; ductile machining is easier to be achieved and surface quality is obviously improved due to ultrasonic assistance in UAMEG. Therefore, larger grinding depth and feed rate adopted in UAMEG can lead to the improvement of removal rate and machining efficiency compared with CMEG.

  9. Controlled cooling technology for bar and rod mills -- Computer simulation and operational results

    Mauk, P.J.; Kruse, M.; Plociennik, U. [SMS Schloemann-Siemag AG, Dusseldorf (Germany)


    The Controlled Cooling Technology (CCT) developed by SMS to simulate the rolling process and automatic control of the water cooling sections is presented. The Controlled Rolling and Cooling Technology (CRCT) model is a key part of the CCT system. It is used to simulate temperature management for the rolling stock on the computer before the actual rolling process takes place. This makes it possible to dispense with extensive rolling tests in the early stages of project planning and to greatly reduce the extent of such tests prior to the start of commercial production in a rolling mill. The CRCT model has been in use at Von Moos Stahl Ag for three years. It demonstrates that, by targeted improvement of the set-up values in both the technology and the plant, it is possible to improve microstructure quality and achieve better geometrical parameters in the rolled products. Also, the results gained with the CCT system in practical operation at the Kia Steel Bar Mill, Kunsan, Korea, are presented.

  10. Walk and roll robot

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)


    A mobile robotic unit features a main body, a plurality of legs for supporting the main body on and moving the main body in forward and reverse directions about a base surface, and a drive assembly. According to an exemplary embodiment each leg includes a respective pivotal hip joint, a pivotal knee joint, and a wheeled foot adapted to roll along the base surface. Also according to an exemplary embodiments the drive assembly includes a motor operatively associated with the hip and knee joints and the wheeled foot for independently driving pivotal movement of the hip joint and the knee joint and rolling motion of the wheeled foot. The hip joint may include a ball-and-socket-type joint interconnecting top portion of the leg to the main body, such that the hip joint is adapted to pivot said leg in a direction transverse to a forward-and-reverse direction.

  11. Roll of honour

    Moxon, Suzanne


    This article gives details of the design and construction of dams selected by members of the dam construction industry for praise as feats of construction. The dams covered in the roll of honour include the dam at the Guri hydroelectric power station in Venezuela on the Caroni river, the Contra dam on the Verzrasca river in Switzerland, and the double curvature arc Ertan dam on the Yalong river in China. (UK)

  12. Rolling bearing analysis

    Harris, Tedric A


    One of the most well-known experts in the field brings cutting-edge research to practitioners in the new edition of this important reference. Covers the improved mathematical calculations for rolling bearing endurance developed by the American Society of Mechanical Engineers and the Society of Lubrication and Tribology Engineers. Updated with new material on Condition-Based Maintenance, new testing methods, and new bearing materials.

  13. Surface Roughness Analysis in the Hard Milling of JIS SKD61 Alloy Steel

    Huu-That Nguyen


    Full Text Available Hard machining is an efficient solution that can be used to replace the grinding operation in the mold and die manufacturing industry. In this study, an attempt is made to analyze the effect of process parameters on workpiece surface roughness (Ra in the hard milling of JIS (Japanese Industrial Standard SKD61 steel, based on a combination of the Taguchi method and response surface methodology (RSM. The cutting parameters are selected based on the structural dynamic analysis of the machine tool. A set of experiments is designed according to the Taguchi technique. The average Ra is measured by a Mitutoyo Surftest SJ-400, and then analysis of variance (ANOVA is performed to determine the influences of cutting parameters on the given Ra. Quadratic mathematical modeling is introduced for prediction of the Ra during the hard milling process. The predicted values are in reasonable agreement with the observation of experiments. In an effort to obtain the minimizing Ra, a single objective optimization is employed based on the desirability function. The result shows that the percentage error between measured and predicted values of Ra is 3.2%, which is found to be insignificant. Eventually, the milled surface roughness under the optimized machining conditions is 0.122 µm. This finding shows that grinding may be replaced by finish hard milling in the mold and die manufacturing field.

  14. Facial lesions in piglets with intact or grinded teeth

    Hansson Monica


    Full Text Available Abstract Background Piglets are born with eight sharp teeth that during nursing can cause facial lesions on littermates and teat lesions on the sow. Teeth grinding in piglets is therefore often practiced to reduce these lesions. The aim of this study was to assess the consequences of grinding piglet teeth in regard to the occurrence of lesions. In this study the piglets' teeth were grinded in 28 litters, and in 36 litters the piglets' teeth were kept intact. Twice, one time during the first week and one time during the second week after birth facial lesions of the piglets were scored and the teats of the sows were examined for lesions. The facial lesion score accounted for the amount and severity of lesions. The individual observations on piglets in the litter were synthesized in a litter facial lesion score. Findings 69.8% and 43.5% of the piglets had facial lesions in week 1 and week 2 respectively. The effect of treatment was not significant on litter facial lesion score. The litter facial lesion score was higher in week 1 than in week 2 (p p = 0.003 than in small litters. Mortality between week 1 and week 2 was higher in litters with intact teeth (p = 0.02. Sow teat lesions only occurred if litters had intact teeth. Conclusions According to our results teeth grinding is only justifiable in large litters.

  15. The Graduate Grind: A Critical Look at Graduate Education

    Michelle K. McGinn


    Full Text Available Abandonment, abuse, anxiety, betrayal, bitterness, breaking point, burnout, collapse, danger, death, desperation, discouragement, divorce, exhaustion, frustration, grind, hardships, hazing, hurdles, ignorance, impossible dream, isolation, killing the spirit, leaving, loneliness, murder, neglect, peril, ridicule, ritual, self-protection, sexual harassment, shock, snobbery, strain, strangulation, stress, suffering, suicide, survival of the fittest, trauma, and violence.


    Ján Kráľ


    Full Text Available Worm gears are special gears consisting of a worm wheel and a worm. Worm gears can be produced in different ways, depending on the size of the transmission, the number of courses, the pitch angle of worm profile, the number of units produced, the purpose of application, etc. As cylindrical worm gears we consider the cylindrical worms with globoid gears, globoid worm with globoid worm gear and globoid worm with cylindrical worm gearing. This paper deals with the evolvent worm whose curve of the tooth side in the front plane is evolvent. The production of worm with an optimal profile for optimal meshing conditions is an increasingly frequent focus of worm gear manufacturers. The problem of designing the tool cutting edge can be divided into several steps. This article deals with the problems of optimum design of a tool shape for the production of worms; and the problems of calculating the coordinates of the transition cutting edge shape, and thus the path of grinding wheel for sharpening the tool cutting edge shape are solved. By grinding tool of grinding machine we can complete the worm shape and also sharpen the cutting edges of tools for production of worm surface. The problems of calculation of the coordinates are solved with regard to the functioning of the KON 250 CNC grinding machine logic.

  17. Cobalt exposure in a carbide tip grinding process.

    Stebbins, A I; Horstman, S W; Daniell, W E; Atallah, R


    Reports relating hard metal disease or nonspecific respiratory symptoms to tungsten or cobalt exposure have been published in the past 20 yr. This report discusses a work site investigation of a small company, employing approximately 50 workers, producing carbide tip saw blades for the woodworking industry. Cobalt exposure was characterized by ambient air monitoring (area and personnel), particle size determination, and biological monitoring. Area sampling for cadmium, cobalt, and tungsten indicated low ambient air levels in all manufacturing areas except the grinding department, which had cobalt air levels approaching the threshold limit value of 0.05 mg/m3. Area airborne cobalt exposure levels measured over six shifts in the grinding department ranged from 0.017 to 0.12 mg/m3 for the total collection method and 0.002 to 0.028 mg/m3 for the method collecting respirable particles. Cobalt content in the total and respirable fractions was similar. Urine monitoring indicated production workers have elevated cobalt levels, and the grinders' levels were higher than other production workers. The grinding coolant was found to have elevated cobalt concentrations. A survey of coolants from nine carbide grinding shops indicated the elevated cobalt concentrations may be common.

  18. Contact and Non-contact Measurements of Grinding Pins

    Magdziak Marek


    Full Text Available The paper presents the results of contact and non-contact measurements of external profiles of selected grinding pins. The measurements were conducted in order to choose the appropriate measuring technique in the case of the considered measurement task. In the case of contact measurements the coordinate measuring machine ACCURA II was applied. The used coordinate measuring machine was equipped with the contact scanning probe VAST XT and the Calypso inspection software. Contact coordinate measurements were performed by using of different measurement strategies. The applied strategies included different scanning velocities and distances between measured points. Non-contact measurements were conducted by means of the tool presetter produced by the Mahr company. On the basis of gained results the guidelines concerning measurements of grinding pins were formulated. The measurements of analyzed grinding pins performed by means of the non-contact measuring system are characterized by higher reproducibility than the contact measurements. The low reproducibility of contact measurements may be connected with the inaccuracy of the selected coordinate measuring machine and the measuring probe, the measurement parameters and environmental conditions in the laboratory where the coordinate measuring machine is located. Moreover, the paper presents the possible application of results of conducted investigations. The results of non-contact measurements can be used in the simulation studies of grinding processes. The simulations may reduce the costs of machining processes.

  19. Fatigue Tests on Welded Joints Improved by Grinding

    Agerskov, Henning; Bjørnbak-Hansen, Jørgen; Olesen, John Forbes

    The present project is a part of an investigation on the fatigue life of the welded structure of large two-stroke diesel engines. Of special interest has been a study of the improvement in fatigue life, due to grinding of the weld toes. The test series carried through showed a significant increase...

  20. Investigation of glycerol polymerization in the clinker grinding process

    Parvulescu, A.N.; Rossi, M.; Della Pina, C.; Ciriminna, R.; Pagliaro, M.


    Concrete production is a large scale process that involves high energy consumption. In order to increase the sustainability of this process, the reduction of energy input is necessary. Bio-glycerol was demonstrated to be a highly efficient renewable-based additive in the grinding process for concret

  1. Microstructure studies of the grinding damage in monocrystalline silicon wafers

    ZHANG Yinxia; KANG Renke; GUO Dongming; JIN Zhuji


    The depth and nature of the subsurface damage in a silicon wafer will limit the performance of IC components.Damage microstructures of the silicon wafers ground by the #325,#600, and #2000 grinding wheels was analyzed.The results show that many microcracks,fractures, and dislocation rosettes appear in the surface and subsurface of the wafer ground by the #325 grinding wheel.No obvious microstructure change exists.The amorphous layer with a thickness of about 100 nm,microcracks, high density dislocations,and polycrystalline silicon are observed in the subsurface of the wafer ground by the #600 grinding wheel.For the wafer ground by the #2000 grinding wheel,an amorphous layer of about 30 nm thickness,a polycrystalline silicon layer,a few dislocations,and an elastic deformation layer exist.In general,with the decrease in grit size,the material removal mode changes from micro-fracture mode to ductile mode gradually.

  2. Grooved roll for a high speed twin roll caster

    T. Haga; HIROOKA, K.; H. Watari; S. Kumai


    Purpose: Purpose of this paper is investigation of the effect of roll-surface on the strip-surface. Improvement ofsmall cracks on the strip-surface was tried and effect of groove at the roll surface on the strip surface was shown.Design/methodology/approach: Method used in the present study was high speed twin roll caster withgrooved roll. Two kinds of grooves were used: one was parallel groove and the other was cross groove machinedby knurling and bite attached to a lathe.Findings: Findings ...

  3. Rolling motion in moving droplets

    Sumesh P Thampi; Rama Govindarajan


    Drops moving on a substrate under the action of gravity display both rolling and sliding motions. The two limits of a thin sheet-like drop in sliding motion on a surface, and a spherical drop in roll, have been extensively studied. We are interested in intermediate shapes. We quantify the contribution of rolling motion for any intermediate shape, and recently obtained a universal curve for the amount of roll as a function of a shape parameter using hybrid lattice Boltzmann simulations. In this paper, we discuss the linear relationship which is expected between the Capillary and Bond numbers, and provide detailed confirmation by simulations. We also show that the viscosity of the surrounding medium can qualitatively affect dynamics. Our results provide an answer to a natural question of whether drops roll or slide on a surface and carry implications for various applications where rolling motion may or may not be preferred.

  4. Improving Energy Efficiency Via Optimized Charge Motion and Slurry Flow in Plant Scale Sag Mills

    Raj K. Rajamani


    A research team from the University of Utah is working to make inroads into saving energy in these SAG mills. In 2003, Industries of the Future Program of the Department of Energy tasked the University of Utah team to build a partnership between the University and the mining industry for the specific purpose of reducing energy consumption in SAG mills. A partnership was formed with Cortez Gold Mines, Outokumpu Technology, Kennecott Utah Copper Corporation, and Process Engineering Resources Inc. At Cortez Gold Operations the shell and pulp lifters of the semiautogenous grinding mill was redesigned. The redesigned shell lifter has been in operation for over three years and the redesigned pulp lifter has been in operation for over nine months now. This report summarizes the dramatic reductions in energy consumption. Even though the energy reductions are very large, it is safe to say that a 20% minimum reduction would be achieved in any future installations of this technology.

  5. Operational performance of the photovoltaic-powered grain mill and water pump at Tangaye, Upper Volta

    Martz, J. E.; Ratajczak, A. F.; Delombard, R.


    The first two years of operation of a stand alone photovoltaic (PV) power system for the village of Tangaye, Upper Volta in West Africa are described. The purpose of the experiment was to demonstrate that PV systems could provide reliable electrical power for multiple use applications in remote areas where local technical expertise is limited. The 1.8 kW (peak) power system supplies 120-V (d.c.) electrical power to operate a grain mill, a water pump, and mill building lights for the village. The system was initially sized to pump a part of the village water requirements from an existing improved well, and to meet a portion of the village grain grinding requirements. The data, observations, experiences, and conclusions developed during the first two years of operation are discussed. Reports of tests of the mills used in the project are included.


    Cristóvão Nery Giacomin


    Full Text Available This work shows the development of a tool for computer simulation of steel plate rolling, which allows the calculation of the thermal evolution of the slab, some process parameters such as force, plate thickness, electrical current and torque in the motors. Mathematical models have been implemented and structured in an off-line model, in which all the important characteristics of the rolling line and of the processed steels are available in a database. Furthermore, the simulator has user-friendly interfaces and easy access, with the flexibility to simulate any possible plate rolling mill. Preliminary applications of the simulator are performed to predict novel conditions of plate rolling attending the requirements of the accelerated cooling process, since this technology is being implemented in the Usiminas Ipatinga.


    Antonio Augusto Gorni


    Full Text Available An evaluation is made about the precision of hot strip rolling mill loads at the F1 stand calculated according to the theoretical models of Orowan, Sims, Alexander-Ford, Orowan-Pascoe, Ekelund and Tselikov in comparison to real values got for carbon-manganese steels. In the deterministic approach, without any fit of the calculated values to real data, Orowan, Sims and Alexander-Models show best levels of precision, as expected from the information got in the literature. However, in the semi-empirical approach, after a linear fit between calculated values and real data, Tselikov and Ekelund models show better adequacy to the industrial data, a fact that can be attributed to more significant errors occurring in the sub-models of temperature, tribology and hot strength than in the rolling load models. For its turn, neural network models show the best levels of precision which make very attractive the adoption of this approach.

  8. Interfacial fatigue stress in PVD TiN coated tool steels under rolling contact fatigue conditions

    Carvalho, N. J. M.; Huis in ’t Veld, A.J.; Hosson, J.Th. De


    Titanium–nitrogen (TiN) films were Physical Vapour Deposited (PVD) on tool steel substrates with different hardness and surface roughness, in a Bai 640R unit using a triode ion plating (e-gun) with a high plasma density. The coated substrates were submitted to a rolling contact fatigue test technique (modified pin-on-ring test) to obtain some clarifications of the mechanism of interfacial failure. Tests were run using PVD-coated rings finished by polishing or grinding to produce different sur...

  9. Research on the Monitoring System of CNC Grinding Process Based on Acoustic Emission

    HU Zhongxiang; TENG Jiaxu; YANG Junwei; HUO Xiaojing; SHI Xiaojun


    Using on-line monitoring during the CNC grinding process, the hazard case such as the crushing of grinding wheel and various safety accidents could be avoided, and the optimum time for dressing and replacing grinding wheel could also be determined, and hence, the service life of the grinding wheel could be prolonged and grinding quality could be improved. To overcome the limitation of some traditional techniques in which some parameters including the grinding power and force, torque and so on were monitored, the acoustic emission (AE) technique, which provides high sensitivity and responding speed, were developed in the present paper. The mechanism of AE during grinding was reviewed. Moreover, a virtual AE monitoring system, which could monitor the grinding state under different working conditions during the grinding, has been developed based on the Virtual Instruments technique. Some experiments were also performed on the internal grinder. The results showed that the AE signals became stronger with increasing the main shaft speed and grinding depth or decreasing the distance between the AE sensor and grinding area.

  10. Experimental investigation of abrasive electrodischarge grinding of Ti6Al4V titanium alloy

    R. Święcik


    Full Text Available Purpose: This work is focused on determination of effects of grinding conditions on effectiveness of abrasive electrodischarge grinding (AEDG process applied for removal of machining allowance and forming of surface geometrical texture (SGT. These results were compared with one obtained for conventional grinding.Design/methodology/approach: The experimental investigations of deep-seated surface grinding of Ti6Al4V titanium alloy using CBN grinding wheel with metal bond were the ground for this elaboration. The effectiveness of AEDG process was assessed based on specific tangential grinding force and energy of spark electric discharge and machining results were estimated on geometrical structure parameters.Findings: The effectiveness of machining allowance removal depended on conditions of AEDG process. Significant differences in SGT formed by AEDG process and conventional grinding were revealed.Practical implications: Abrasive electrodischarge grinding is useful to be particularly suitable for efficient and effective grinding of very hard structural materials such as high-alloy steel, sintered carbides, metal-based composite materials etc.Originality/value: AEDG experiments were carried out using the typical surface finishing grinder and especially adapted generator of spark discharge pulses. The majority of such experiments in the world were performed with the electrodischarge machine tool equipped with extra grinding wheel mounted on the grinding pin and functioning as one of the electrodes put into operation via pneumatic drive.

  11. Development of a grinding-specific performance test set-up

    Olesen, C. G.; Larsen, B. H.; Andresen, E. L.


    and an exponentially rising resistance. A custom-made grinding ergometer was developed with computer-controlled resistance and capable of collecting data during the test. The data collected can be used to find measures of grinding performance such as peak power, time to complete and the decline in repeated grinding......The aim of this study was to develop a performance test set-up for America's Cup grinders. The test set-up had to mimic the on-boat grinding activity and be capable of collecting data for analysis and evaluation of grinding performance. This study included a literature-based analysis of grinding...... demands and a test protocol developed to accommodate the necessary physiological loads. This study resulted in a test protocol consisting of 10 intervals of 20 revolutions each interspersed with active resting periods of 50 s. The 20 revolutions are a combination of both forward and backward grinding...

  12. Optimization of operating variables for production of ultra-fine talc in a stirred mill. Specific surface area investigations

    Toraman Oner Yusuf


    Full Text Available Due to its properties such as chemical inertness, softness, whiteness, high thermal conductivity, low electrical conductivity and adsorption properties talc has wide industrial applications in paper, cosmetics, paints, polymer, ceramics, refractory materials and pharmaceutical. The demand for ultra-fine talc is emerging which drives the mineral industry to produce value added products. In this study, it was investigated how certain grinding parameters such as mill speed, ball filling ratio, powder filling ratio and grinding time of dry stirred mill affect grindability of talc ore (d97=127 μm. A series of laboratory experiments using a 24 full factorial design was conducted to determine the optimal operational parameters of a stirred mill in order to minimize the specific surface area. The main and interaction effects on the volume specific surface area (SV,−3 of the ground product were evaluated using the Yates analysis. Under the optimal conditions at the stirrer speed of 600 rpm, grinding time of 20 min, sample mass of 5% and ball ratio of 70%, the resulting talc powder had larger volume specific surface area (i.e., 3.48−3 than the starting material (i.e., 1.84−3.

  13. Influence of clinker grinding-aids on the intrinsic characteristics of cements and on the behaviour of mortars

    Fernández Luco, L.


    Full Text Available In the production of portland cement, grinding aids are used to improve the grinding stage and reduce the energy required to achieve the required fineness. These additives remain in the final product and they might influence the characteristics and properties of the cement, and thus, mortar and concrete. This paper presents an evaluation of two grinding-aid additives used in the production of portland cement ground in a ball mill at a laboratory stage, with suitable proportions of portland cement clinker and gypsum. A control cement mix was also produced without using any admixture and the results are shown on a comparative basis. Conclusions indicate that grinding-aids additives have some influence on the characteristics of portland cement produced, increasing their specific surface and modifying microstructure and its packing ability. Mortars and concretes made with cements ground with the addition of gringing-aids exhibit higher strength at any age and a reduced water demand. Special attention should be taken to consider any interaction with water-reducing admixture in concretes and mortars.

    En la fabricación de cemento portland es una práctica creciente la utilización de aditivos para optimizar el proceso de molienda; éstos quedan incorporados en el producto final y pueden influir sobre las características y propiedades del cemento, morteros y hormigones. En este trabajo se presenta la evaluación de dos aditivos comerciales en la molienda conjunta de clínker de cemento portland y yeso comercial, tratados en un molino a bolas a escala de laboratorio, en forma comparativa con un cemento sin aditivo producido en forma equivalente. Las conclusiones indican que los aditivos de molienda tienen influencia en las características del cemento resultante, incrementando su superficie y modificando su microestructura y estado de agregación; los morteros mejoran sus prestaciones mecánicas a todas las edades y se reduce la demanda de agua

  14. Production of normalized steel plate through normalizing rolling; Producao de chapas grossas normalizadas diretamente do calor de laminacao

    Gorni, Antonio Augusto; Cavalcanti, Celso Gomes; Reis, Jackson Soares de Souza; Silveira, Jose Herbert Dolabela da [Companhia Siderurgica Paulista (COSIPA), SP (Brazil)


    Normalized plates can be got directly from the rolling heat through the use of a normalizing rolling process. In such way, an additional step of the conventional process of production of normalized plates - the normalizing heat treatment - can be suppressed, reducing the manufacturing cost of the product and shortening its production time. This relatively new production route is being used in several steelworks all over the world for many years. This work describes the implementation trials of normalizing rolling at COSIPA`s plate mill, using an alternative process of controlled rolling called recrystallization controlled rolling. The results got with new technique were successful, as it was able to produce plates with properties very similar to the conventionally normalized material, attending the requirements of the DIN 17100 RR 52-3N standard. This is one of many standards that permit the use of this new route of normalized steel plate production. (author) 14 refs., 8 figs., 2 tabs.

  15. Relationship between coal size reduction and energy input in Hardgrove mill

    Zuo Weiran; Zhao Yuemin; He Yaqun; Shi Fengnian; Duan Chenlong


    Hardgrove grindability index (HGI) is an important indicator of coal grindability,and is one of the most important parameters to determine the capacity of coal pulverizer in power station.However,HGI is an empirical grindability index without linkages to any known physical parameters.To investigate the effect of energy input on the grinding in Hardgrove mill,a T20WN torque meter was installed on the shaft of a modified Hardgrove mill to record the torque driving the mill.Samples from four kinds of coals with HGI ranging from 36 to 72 were prepared according to the procedure of standard HGI test and ground in a modified Hardgrove mill at different revolutions.The relation of sample size reduction degree to specific comminution energy (Ecs) was studied with Shi-Kojovic model.The results show that Shi-Kojovic model predicted well the coal size reduction degree with Ecs in Hardgrove mill.The grindability index given by Shi-Kojovic model has a similar trend with HGI.The relation of sample size reduction degree to Ecs reveals that HGI has a non-linear relationship with effective specific energy in Hardgrove mill,which explains the non-linear relation of HGI to industrial pulverizer capacity.

  16. LEDs are on a roll

    Blom, P.W.M.; Mol, A.M.B. van


    Light-emitting diodes are more efficient than conventional lighting, but high production costs limit their uptake. Organic versions that can be produced using a cheap newspaper-style 'roll-to-roll' printing process are likely to revolutionize our lighting and signage, say Paul Blom and Ton van Mol.

  17. Rudder roll stabilization for ships

    Amerongen, van J.; Klugt, van der P.G.M.; Nauta Lemke, van H.R.


    This paper describes the design of an autopilot for rudder roll stabilization for ships. This autopilot uses the rudder not only for course keeping but also for reduction of the roll. The system has a series of properties which make the controller design far from straightforward: the process has onl

  18. Preparation of glibenclamide nanocrystals by a simple laboratory scale ultra cryo-milling

    Martena, Valentina; Censi, Roberta [University of Camerino, School of Pharmacy (Italy); Hoti, Ela; Malaj, Ledjan [University of Tirana, Department of Pharmacy (Albania); Martino, Piera Di, E-mail: [University of Camerino, School of Pharmacy (Italy)


    The objective of this study is to evaluate the ability to reduce the particle size of glibenclamide (GBC) to the nanometric scale through a very simple and well-known laboratory scale method, the laboratory scale ultra cryo-milling. The effect of milling on GBC crystalline properties and dissolution behaviour was deliberately evaluated in the absence of any surfactants as stabilizers. The milling procedure consisted in adding particles to liquid nitrogen and milling them by hand in a mortar with a pestle for different time intervals (15, 30, 40 min). For comparison, the same milling procedure was also applied without liquid nitrogen. The particle size reduction was evaluated for the coarsest samples (>3 {mu}m) by measuring the particle Ferret's diameter through scanning electron microscopy, while for the smallest one (<3 {mu}m) by dynamic light scattering. A time grinding of 40 min in the presence of liquid nitrogen was revealed highly efficacious to obtain particles of nanodimensions, with a geometric mean particle size of 0.55 {+-} 0.23 {mu}m and more than the 80 % of particles lower than 1,000 nm. Interestingly, non-agglomerated particles were obtained. Differential scanning calorimetry and X-ray powder diffractometry allowed to assess that under mechanical treatment no polymorphic transitions were observed, while a decrease in crystallinity degree occurred depending on the milling procedure (presence or absence of liquid nitrogen) and the milling time (crystallinity decreases at increasing milling time from 15 to 40 min). A comparison of the intrinsic dissolution rate and the dissolution from particles revealed an interesting improvement of particle dissolution particularly for particles milled in the presence of liquid nitrogen due to an increase in particle surface area and concentration gradient, according to the Noyes-Whitney equation.

  19. Computational design of rolling bearings

    Nguyen-Schäfer, Hung


    This book comprehensively presents the computational design of rolling bearings dealing with many interdisciplinary difficult working fields. They encompass elastohydrodynamics (EHD), Hertzian contact theory, oil-film thickness in elastohydrodynamic lubrication (EHL), bearing dynamics, tribology of surface textures, fatigue failure mechanisms, fatigue lifetimes of rolling bearings and lubricating greases, Weibull distribution, rotor balancing, and airborne noises (NVH) in the rolling bearings. Furthermore, the readers are provided with hands-on essential formulas based on the up-to-date DIN ISO norms and helpful examples for computational design of rolling bearings. The topics are intended for undergraduate and graduate students in mechanical and material engineering, research scientists, and practicing engineers who want to understand the interactions between these working fields and to know how to design the rolling bearings for automotive industry and many other industries.

  20. Teeth Grinding: Is Emotional Stability related to Bruxism?

    Sutin, Angelina R.; Terracciano, Antonio; Ferrucci, Luigi; Costa, Paul T.


    This study examines the association between personality traits and bruxism, the repetitive grinding or clenching of teeth. Community-dwelling participants (N = 470) had a comprehensive oral examination by a dentist and completed a dental history and personality questionnaires. Consistent with the literature on state anxiety and depression as antecedents of bruxism, Neuroticism-related traits were associated with self-reported teeth grinding. These traits were also associated with other oral complaints often associated with anxiety (jaw clicks, difficulty chewing food, and dry mouth), but not with more general oral health complaints (unhealthy gums, bleeding gums, and canker sores) or with dentist-assessed occlusal wear or tongue indentations. This study provides evidence for the association between Neuroticism and bruxism and other stress-related oral health symptoms. PMID:20835403