CVC轧辊辊形参数的确定

对CVC轧辊的辊形曲线进行数学解析,研究轧辊的轴向移动量与轧辊有效凸度的关系,推导辊形参数的理论计算公式,得到从工艺角度出发计算辊形系数A1的公式,并对某CSP厂CVC轧辊技术参数进行计算,提出其辊形参数的修正建议。     

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

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.     

六辊CVC轧机轧辊弯曲和压扁变形的有限元分析

采用非线性弹塑性有限元法,利用大型非线性有限元软件MSC.Marc建立了六辊CVC轧机轧制过程三维有限元仿真模型。模型将辊系弹性变形与轧件弹塑性变形耦合在一起,进行统一建模与分析。运用该模型分别改变工作辊弯辊力、中间辊弯辊力、中间辊横移量进行有限元模拟,得到了工作辊弯辊、中间辊弯辊、中间辊横移对六辊CVC轧机轧辊弯曲和压扁变形的影响规律。所建模型与分析结果可为六辊CVC轧机的板形控制研究提供理论数据与参考依据。     

基于板形性能优化目标的支承辊辊形设计

研究了宽板带轧机辊形设计的原理和方法,提出了一种基于板形性能优化目标的支承辊辊形设计理念,并在某冷轧机组应用所设计的辊形,改善了支承辊磨损,提高了轧机的板形控制能力.     

UC轧机中间辊非对称弯辊改善辊间压力分布

为了改善UC轧机辊间压力不均匀分布问题,采用中间辊非对称弯辊系统替代原有对称弯辊系统.应用影响函数法计算辊系变形,同时考虑辊缝中金属横向流动对带钢出口张力横向分布的影响,通过迭代方法计算出中间辊两端施加不同弯辊力后的辊间压力分布、出口厚度横向分布与出口张力横向分布.理论分析和实际应用结果表明,中间辊非对称弯辊可以改善辊间压力分布不均,降低轧辊磨损和减少轧辊辊面剥落,且不会影响成品带钢的厚度和板形.     

WRS轧机工作辊磨损计算及板形调控分析

在热带钢连轧机设计及改造中采用WRS辊系作为下游机座可以增强机组的板形调控能力。从理论上分析了辊系在轧制中的磨损特性，工作辊磨损辊型的计算方法，根据实际轧制工况对其板形的调控、影响因素进行了定量分析。     

Improved model to solve influence coefficients of work roll deflection

According to the concept of virtual bending force, a rational explanation for SHOHET’s model was presented. Considering the deformation characters of the work rolls in four-high mill, the deformation model of the work roll was regarded as a cantilever beam and new influence coefficients were deduced. The effect of the bending force was taken into account independently. Therefore, the contribution to work roll deflection caused by rolling load, rolling pressure between rolls and bending force can be got from the new formulas. To validate the accuracy of the formulas, the results obtained from the new formulas were compared with those from SHOHET’s formulas. It is found that they highly coincide, which illustrates that the formulas are reliable.     

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

The roll contour pattern and variety of work and backup rolls 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.     

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

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 ac- curacy 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 re- quirement) 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.     

Backup roll contour of a SmartCrown tandem cold rolling mill

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.     

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

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 gauge-meter model.     

Backup roll contour in finishing trains of hot rolling based on hybrid genetic algorithm

On the basis of integrating two-dimensional varying thickness finite element method with hybrid genetic algorthm,a precise model was developed to design ideal backup roll contour(Varying Contact Backup Roll,inshort VCR) in finishing trains of hot rolling rapidly and efficaciously,Additionally,a lot of good actual effects of VCR,such as evident improvement of profile and flatness of strip,remarkable decrease of roll consume,excellent maneuverability and maintenance,and so on,were validated by long-tem industrial tests in hot rolling strip plant of Wuhan Iron and Steel Group Corporation(WISCO).     

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

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 profile and flatness control of nonoriented electrical steel sheets in hot strip mills.     

采用多项式回归方法建立CVC辊形曲线方程

介绍了CVC技术改善板形的基本原理。CVC技术就是轧辊连续可变凸度技术,有了轧辊连续可变凸度,就可使轧辊的凸度在最大值与最小值之间连续无级可调,从而达到改善板形的目的。根据实测数据,采用多项式回归方法,建立CVC辊形曲线方程,并探讨了该方程的重要实际意义。     

提高车辆转向稳定性的车身主动侧倾控制研究

车辆高速转向时，车身向弯道外侧倾斜，严重时会导致侧翻事故.针对此问题，开展了提高车辆转向稳定性的车身主动侧倾控制研究.首先建立了考虑横摆和侧倾运动的六自由度车辆动力学模型；然后确定了车辆在转向运动时的期望侧倾角，并以此为控制目标设计主动侧倾控制器，使车身实际侧倾角逼近期望侧倾角.在不同行驶工况下，仿真研究了车身侧倾角、乘员感知加速度和横向载荷转移率，并考察了实现主动侧倾控制所需的主动悬架功耗和由主动侧倾引起的悬架动挠度变化.研究结果表明：主动侧倾控制能实现车辆转向时实际侧倾角迅速逼近期望侧倾角，且在复杂行驶工况下依然能使车辆具有良好的行驶稳定性；主动侧倾控制减小了悬架的动挠度峰值，使乘员感知侧向加速度和横向载荷转移率都能快速接近零值，且实现主动侧倾的主动悬架功耗较小，保证了车辆的经济性能.     

Q450冷弯成型角钢有限元数值模拟

采用非线性有限元法对冷弯成型过程中角钢各部位的应力、应变分布情况进行分析,并揭示了角钢在成型过程中金属的变形规律。结果表明,有限元模拟得出的板材应力、应变分布规律与实际情况相符舍,冷弯回弹模拟结果与实测回弹值存在一定的误差,模拟结果中回弹角随着成型角增加时的变化规律与实测结果一致。采用非线性有限元法对冷弯成型过程进行数值模拟是可行的。     

弯辊和串辊对带钢板形影响

基于有限元软件ANSYS建立了冷轧六辊轧机的三维弹塑性有限元参数化模型。将轧机实体模型转换成有限元模型,根据轧机的工作方式提炼出边界条件和载荷条件,施加在有限元模型上。参数化模型采用ANSYS参数化设计语言APDL编写。通过修改程序中的参数,计算分析了弯辊力、中间辊的串辊量以及带钢宽度等参数对带钢形状和辊缝的影响。计算结果表明:当带钢宽度小于1 300 mm时,调整弯辊力对带钢板形的改变较为明显;当带钢宽度大于1 700 mm时,调整弯辊力对改变带钢板形的作用变得非常小,此时通过连续可变凸度轧辊（CVC）的串辊来调节板形更有效。该结论与冷轧厂实践结论一致。     

PC轧机辊系的三维建模与有限元分析

采用三维有限元法(ANSYS)建立PC轧机辊系的模型,并分析了PC轧机在不同工况下辊系弹性变形与工作辊/支撑辊的接触压力.计算结果表明,影响PC轧机轧件截面形状的主要因素是对辊交叉所产生的等效辊凸度.文中采用的建模与分析方法与其它方法相比,计算结果更为精确、可靠.     

Development of centrifugal casting high speed steel rolls

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/cm2. The results of on-line service investigation in high speed wire rod mill indicate that the HSS rolls have excellent wear resistance, the     

逆涂模式下辊间涂液的参数分析

针对逆式辊涂过程将涂敷辊与汲料辊之间的液体流动简化成两无限大平板间的黏性流动,结合流体动力润滑理论和毛细效应条件建立辊涂数学模型,并对方程进行求解。重点研究在涂敷辊分别为刚辊和胶辊的情况下,辊涂参数（辊速比、辊半径、涂液表面张力、入口油膜厚度和辊间间隙）对辊间涂液的影响。结果表明,各参数对涂层液珠均有影响,其中辊速比在涂敷辊为刚辊或胶辊时都是影响涂层油膜厚度的重要因素。