1420mm连轧机精细冷却系统的应用

在五机架冷连轧机中,末机架轧辊分段冷却能够改善板形,有效消除板形缺陷,精确的轧辊冷却能够有效释放轧辊内应力,延长轧辊使用寿命,提高轧制带材板形质量和表面清洁度。以1420mm冷连轧机的板形控制系统为依据,针对轧制极限薄板时轧机震动和出口带材温度高等现象,综合分析该精细冷却控制系统的功能与应用效果。     

基于线性化模型的冷连轧机PI解耦控制系统

冷连轧动态规格变换过程实现控制的主要困难在于冷轧过程中厚度、张力等被控变量之间的相互耦合作用。文中提出了一种基于线性化模型的冷连轧机PI解耦控制方案，仿真结果证明该方法的有效性。     

冷轧带钢边部减薄和平坦度模糊预测控制的研究

针对配备轧辊横移的新型四辊冷连轧机边部减薄控制控制中,轧机模型具有多变量间的强耦合、易变的模型参数、不确定的干扰因素和不稳定的动态特性,设计一种复合的智能控制系统。设计在模糊控制基础上增加一个积分环节的控制器,与轧机预测模型相结合对带钢边部减薄和平坦度进行闭环控制。经过仿真结果表明,该控制系统可实现四辊冷连轧机边部减薄的稳定跟踪控制及边部减薄和平坦度的非线性解耦控制。     

板带轧机柔性多体系统耦合动力学建模研究

轧制过程中,高速运转的板带轧机系统可视为由机架、液压装置、轴承座和轧辊等多个刚体和可变形体组成的柔性多体机械系统。板带轧机辊系沿垂直、水平方向的刚体运动和轧辊沿轴线方向的柔性体变形运动是影响板带厚度和表面质量的主要因素。特别对于大型板带轧机而言,轧辊的弯曲变形运动与带钢的板形密切相关。本文综合考虑轧机系统沿垂直、水平方向的刚性振动和轧辊沿轴线方向的弯曲变形运动之间的耦合效应,通过运动学分析,实现柔性多体机械系统中刚体和可变形体的位移场描述,建立板带轧机辊系刚柔耦合动力学模型。对轧机辊系进行耦合运动模态分析,进一步探讨轧辊变形运动振动频率和模态振型函数的精确解,并比较不同时刻下,由传统结构动力学求得的轧辊固有模态振型函数与考虑轧机系统刚性振动时的轧辊模态振型函数的区别。深入分析了轧机系统刚性振动对轧辊弯曲变形运动的影响,为提高轧辊运动精度,实现带钢板形动态控制提供理论依据。     

四辊轧机滚动轴承偏载与板形影响因素分析

为了分析板带轧机滚动轴承列间偏载和板形的变化规律,利用ANSYS/LS-DYNA有限元软件建立了耦合轧件、工作辊、支撑辊及其轴承座的轧制过程整体变形分析模型,分析了辊径、摩擦系数、变形抗力及张力对轴承载荷分布和板凸度的影响。研究结果表明,轴承偏载程度和板凸度随轧辊半径和张力的增大而减小,随变形抗力的增大而增大;轴承偏载程度随摩擦系数的增大而增大,板凸度随摩擦系数的增大略有减小;轴承偏载程度与板凸度的变化呈显著正相关。研究结果可为板带轧机滚动轴承的使用和板形控制提供有益参考。     

四辊轧机轧制因素影响磨损的有限元分析

轧制过程中,轧辊与被轧制金属材料之间接触应力较大,并承受周期性的应力应变。轧辊的表面特性会发生改变,产生磨损。轧辊与带钢之间的磨损会落破坏原始辊型,并直接影响板形控制精度及增加辊耗。对于轧制因素的调整,可以降低辊耗和节约生产成。首先分析了轧辊的磨损及影响因素,考虑轧辊辊系的弹塑性变形,基于有限元软件,建立了轧制力学模型以及四辊轧机有限元仿真模型。其次利用有限元法对轧辊的应力进行了仿真模拟,并从板宽、压下率等因素对工作辊磨损的影响,提出了降低轧辊失效的具体措施。     

冷连轧机组兼顾板形与板凸度的压下规程优化

针对以往现场生产过程中压下规程的设定主要考虑轧制负荷均衡、打滑与热滑伤的防治,而对板形与板凸度的控制考虑较少的问题,结合UCM冷连轧机组的设备与工艺特点,兼顾轧制负荷均衡、打滑与热滑伤的防治与板形及板凸度的控制,提出了一套适合于五机架UCM冷连轧机组的压下规程综合优化方法,并将其推广应用到生产实践,取得了良好的使用效果。     

四辊轧机有载辊缝解析模型研究

针对轧制过程中轧辊的弹性变形和轧辊与轧件间的相互作用，通过对四辊轧机辊系变形和受力状况的分析，从理论上详细推导了直观的有载辊缝形状函数，明确了有载辊缝形状函数与相关因素的对应关系。同时，为了验证辊缝解析模型的准确性，采用该模型对某铝热连轧机的精轧末机架的出口板凸度进行了理论计算，并与在线测得数据进行比较，结果表明：该模型计算精度高，相对误差较小(低于15％)。该模型不但为板形的控制以及轧制板凸度的建模提供了理论基础，还为预报板形、研究板带截面上任一点的板凸度提供了方便。     

UCM冷连轧机辊型曲线优化设计

以900mm四机架六辊UCM冷连轧机组为研究对象,建立了轧辊辊间接触压力和板形计算模型,以均匀辊间接触压力分布和板形良好为目标,对机组轧辊辊型曲线进行了优化设计.理论计算表明,优化后的辊型曲线均匀了辊间接触压力分布,降低了辊端接触压力峰值,同时能够提高弯辊力对板形的控制效果.工业生产试验后正式推广使用,支承辊和中间辊掉肩和掉肉现象得到了全面遏制,板形质量得到良好控制.     

四立柱分体式20辊轧机辊系的刚度特性分析

20辊轧机的横向刚度、纵向刚度对板形、板厚的控制非常重要,研究不同状态下轧机的刚度变化规律对板形、板厚综合控制的精度具有十分重要的意义。在三维弹性有限元模型的基础上,建立了四立柱分体式20辊轧机辊系的有限元模型。利用该模型研究板宽、中间辊窜辊量变化对轧机辊系横向刚度和纵向刚度的影响,为轧机板形、板厚控制量的调整提供了参考依据,也为板带轧制过程中板型、板厚在线设定,以及控制模型的研究和优化,提供了理论基础。     

SENSITIVITY ANALYSIS FOR ROLLING PROCESS BASED ON SUPPORT VECTOR MACHINE

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 control variable of the thickness control system in the first stand.     

Tandem Strip Mill’s Multi-parameter Coupling Dynamic Modeling Based on the Thickness Control

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.     

薄带钢冷连轧横向厚差控制理论及DI材横向厚差控制技术研究

针对软质、宽幅、薄带钢冷连轧过程横向厚差(凸度和边降两个指标描述)的生成与控制问题,运用ABAQUS有限元软件建立冷连轧过程辊系-轧件一体化仿真模型,定义用以反映冷连轧各个机架对成品带钢横向厚差控制的贡献大小的指标——横向厚差控制权重,深入研究冷连轧过程带钢横向厚差的生成、遗传规律和其中凸度与边降的相互耦合影响,探索研究软质薄带钢冷连轧过程中横向厚差控制策略及针对DI材的横向厚差控制技术。仿真研究发现,冷连轧机的前两个机架具有远高于其他机架的横向厚差控制权重,是连轧机组中最适于也最有效的控制横向厚差的机架;一般地,第1机架的权重大于第2机架,但带钢材质越软、厚度越薄,第2机架的权重越大,尤其对于极薄且软的带钢,第2机架可以具有大于第1机架的权重;冷连轧过程中通过板形调控机构调控横向厚差时,各机架处带钢边降与凸度的耦合程度从第1架到第5架逐步提高。结合仿真分析结果,研究提出针对国内某1420冷连轧机的DI材横向厚差控制的总体策略和系列技术,并在生产试验后投入长期稳定使用,使该机组的DI材横向厚差控制精度合格率从过去的76.25%提高至92.10%。     

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

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 strip shape quality.     

冷连轧动态变规格及厚度预设定的研究

研究冷连轧机的动态变规格技术,对于维持轧机的正常生产,提高产品产量和质量具有非常重要的意义.以常规的五机架冷连轧机作为研究对象,给出了五机架冷连轧机的动态变规格的计算公式,分析厚度、轧制力、流量、速度、张力的组成及模型,并对模型进行简化,针对动态变规格及其厚度的预设定应用VB编写界面,进行仿真,效果清晰,突出表现了变规格在厚度预设定方面的作用.     

冷连轧机相对油膜厚度的测试与建模

为了分析冷连轧机支撑辊动压油膜轴承的油膜厚度变化对带钢厚度的影响,提高轧机AGC精度,进行了油膜厚度测试实验。对某1450mm五机架冷连轧机进行空压靠,在不同转速和轧制力条件下,记录液压缸缸位移变化值。根据实测数据,建立油膜厚度增量模型,运用Levenberg-Marquardt法拟合出该套轧机的油膜厚度模型参数。实测数据分析表明,油膜厚度随转速增加而增加,并随转速的进一步增加而变化趋势减缓。该研究为轧机厚度方程中油膜厚度补偿量的选取提供了可靠的依据。     

变权重指数平滑法在冷轧过程控制中的应用

冷轧机组在轧制过程中很多状态都是在时刻变化的。轧辊直径、温度、粗造度、轧件来料厚度、硬度的变化、机架间张力的波动、各个调节器特性的变动、仪表零点的漂移等都会影响模型计算的精度。故在轧制过程中引入自适应自学习技术是提高模型计算精度的一种很好的选择。冷轧过程控制系统自适应算法通常采用指数平滑法,为了提高自适应速度往往采用变权重指数平滑法。     

STUDY ON STRIP AND ROLL DEFORMATION COUPLING OF COLD STRIP ROLLING ON 4-H MILL

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Study on the improved accuracy of strip profile using numerical formula model in continuous cold rolling with 6-high mill

The quality requirements for thickness accuracy in cold rolling continue to become more stringent. In cold rolling mill, it is very important that the rolling force calculation considers rolling conditions. The rolled strip thickness was predicted using calculated rolling force. However, the prediction of strip thickness in cold rolling is very difficult; in particular, for 6-high mill with shifted intermediate roll (IMR), the accuracy of thickness is not good. In this study, to improve the accuracy of rolled strip thickness, the roll gap flattening can be given based on Hertz contact theory, with contact between rolls and the smooth cylindrical rolls for the rolling elastic deformation. Also, the distribution of the roll gap flattening may be calculated using the contact force of unit transverse length. The strip profile at the continuous cold rolling is calculated by using the numerical analysis model considering the initial strip profile before cold rolling. Hence, we propose that the numerical model can predict the rolled strip profile more quickly and accurately and be applicable to the field. The results of the proposed numerical model were verified by FE-simulation and cold rolling experiments of 6-high mill with five stands.