超宽六辊CVC轧机的凸度调控能力分析

为掌握超宽六辊CVC轧机的凸度调控能力,建立有限元仿真模型,对不同带钢宽度下工作辊弯辊、中间辊弯辊和CVC中间辊窜辊对板廓的影响进行具体分析。仿真结果表明,工作辊弯辊、中间辊弯辊和中间辊窜辊均具有相似的调节效果,对于1000mm的带钢,工作辊弯辊的调控能力最强;对于1500mm的带钢,工作辊弯辊和中间辊窜辊的调控能力相当;对于2000mm的带钢,中间辊窜辊的调控能力最强。因此,对于超宽轧机,CVC窜辊对窄带钢的凸度调控效果并不十分理想,会导致轧制窄带钢时出现凸度控制能力不足的问题。通过对凸度调节域进行分析,发现该轧机对四次凸度的控制能力较弱,难以控制超宽带钢生产中的边中复合浪形问题。     

热带钢轧机线性变凸度工作辊的研制及应用

为改善轧机的板形调控性能,在分析连续变凸度(Continuously variable crown,CVC)辊形技术的板形控制特性的基础上,开发出用于热带钢轧机的线性变凸度(Linearly variable crown,LVC)工作辊辊形技术及其相应的板形控制模型。LVC技术的板形调节能力与窜辊量成线性关系,同时与带钢宽度成近似线性关系。在满足宽带钢板形控制要求的同时,提高轧机对窄带钢的板形控制能力,使轧制各种规格带钢时所需弯辊力处于合理的的幅值。在1 700 mm热带钢轧机上一年多的工业应用表明,采用LVC工作辊后,板形控制精度提高30%以上,尤其是轧制高强度钢种时,凸度下降显著,轧制公里数一般都大于55 km,磨损辊形和轧辊消耗与常规工作辊基本一致。     

冷轧机板形调节能力分析方法的研究与应用

某六辊连续变凸度(Continuously variable crown,CVC)冷轧机组装备了工作辊弯辊、中间辊弯辊和中间辊窜辊等多种板形控制方式,较四辊轧机有着更宽的凸度调节域,但仍难以调节窄带钢出现的边中复合浪。在对各种方式的效应函数之间的差别进行分析后,提出以一组相互正交的矢量,称为特征矢量,描述轧机整体的板形调节特性。进而以特征矢量与某一板形缺陷之间的相似度的平方和判断该缺陷能否被消除。经分析,该轧机板形调节特征矢量与窄带钢边中浪之间的相似度过低是导致其难以消除的原因。相应提出在第5机架采用单侧倒角工作辊,并降低工作辊弯辊力的解决方案。该方案已用于实际生产,在消除带钢边中浪方面取得明显效果,所轧带钢边浪基本被消除,中浪得到缓解。     

冷轧无取向硅钢横向厚差控制

冷轧中中低牌号的无取向硅钢多采用万能凸度轧机(Universal crown mill,UCM)生产,其板形好坏受制于UCM轧机板形调节手段的协调使用.为掌握UCM轧机的板形控制特点,建立基于二维变厚度有限元的辊系弹性变形和基于三维差分的轧件塑性变形的六辊轧机耦合模型,对UCM轧机的板形调控性能进行详尽的分析,包括工作辊和中间辊弯辊、中间辊窜辊的调控功效、辊间接触压力分布等.在此基础上,提出可用指导生产的板形控制策略,指出UCM轧机在横向厚差控制方面的不足.针对工业生产中UCM轧机轧制无取向硅钢横向厚差大的问题,在大量仿真计算的基础上,开发具有高次曲线函数的边部变凸度(Edge variable crown,EVC)的工作辊.采用该工作辊后,各种品种的无取向硅钢的横向厚差不大于10 μm的百分比由24%提高到99%,横向厚差的均值小于6μm,远小于之前的13μm.     

宽带钢六辊冷连轧机横向刚度特性研究

板带轧机的横向刚度对于板形控制十分重要,研究轧机不同状态下的横向刚度变化规律对于实现板形的精确控制具有重要意义。本文针对某厂六辊轧机利用有限元软件ANSYS9.0建立了三维辊系有限元分析模型,分别分析了不同工作辊窜辊和中间辊窜辊下的轧制力横向刚度和弯辊力横向刚度的变化情况,为轧机板形控制量的调整提供了参考依据。     

万能凸度轧机非对称板形调控特性与广义整体板形控制策略研究

随着板形质量精度要求的不断提高以及板形控制技术的显著进步,非对称板形缺陷逐渐凸显为带钢轧制质量控制的重要技术难点。根据目前新建万能凸度轧机(Universal crown mill,UCM)逐渐具备新型非对称板形控制手段——反对称弯辊的有利条件,通过ANSYS有限元仿真计算软件,建立高精度辊系—轧件一体化耦合模型,分析UCM各对称与非对称板形控制手段沿带钢全宽调控特性的差别,并以板形调控功效矢量的形式进行定量表示。在仿真基础上,提出基于板形调控功效矢量的广义整体板形控制策略,并设计完整的板形设定计算模型与闭环控制模型。通过仿真试验表明,该控制策略能够很好地通过各对称与非对称板形控制手段的有效配合实现对复杂模态板形的有效控制,具有广阔的研究与应用前景。     

板带轧机工作辊混合变凸度辊形研究

三次连续变凸度(Continuously variable crown, CVC)辊形凸度控制能力与带钢宽度之间的二次函数关系决定其在宽、超宽板带轧机上应用时表现出对窄规格带钢的凸度控制能力不足的缺点。通过对工作辊变凸度辊形及辊缝形成理论的深入研究,提出采用二次多项式曲线来线性化辊缝的方法。采用该方法设计完全线性变凸度辊形曲线与混合变凸度工作辊辊形曲线,使二次辊缝凸度调节能力与带钢宽度在工作辊全长或在设计要求的宽度范围内呈严格线性关系,同时保持与窜辊位置呈线性关系。与CVC辊形相比,混合变凸度辊形的辊径差小、凸度调节能力大,既不削弱对宽带钢的凸度调节能力,又增加对窄带钢的凸度调节能力,从而增强轧机的整体板形控制能力。     

热轧宽带钢自由规程轧制中机型的配置

为了提高自由规程轧制中热连轧机的板形调节能力,提出了热轧宽带钢的机型配置方案。新机型的特点在于轧机的上游机架采用线性变凸度工作辊技术,下游机架使用锥形工作辊技术,全机组采用变接触轧制技术和强力弯辊。生产实绩表明,新机型配置方案使得宽带钢热连轧机板形控制性能大幅提高,能够适应自由规程轧制的需求。     

热轧宽带钢自由规程轧制中机型的配置

为了提高自由规程轧制中热连轧机的板形调节能力,提出了热轧宽带钢的机型配置方案。新机型的特点在于轧机的上游机架采用线性变凸度工作辊技术,下游机架使用锥形工作辊技术,全机组采用变接触轧制技术和强力弯辊。生产实绩表明,新机型配置方案使得宽带钢热连轧机板形控制性能大幅提高,能够适应自由规程轧制的需求。     

连退平整机组带钢过焊缝过程中板形控制技术研究

针对连退平整机组带钢过焊缝过程中板形波动的问题,充分考虑连退平整机组的设备与工艺特点,以中间辊弯辊力对轧制压力进行补偿,以工作辊弯辊力对前后张力进行补偿,建立了板形控制模型。通过理论模型与现场试验相配合,实现了中间辊弯辊力和工作辊弯辊力的动态补偿,最大程度地减少了板形的波动幅度。     

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.     

四辊CVC热带钢轧机板形控制特性的仿真

用流面条元法分析带材的三维塑性变形．用影响系数法分析辊系的弹性变形，将两者耦合，建立了四辊轧机板形和板凸度的分析计算模型。对四辊CVC热带钢轧机板形控制特性的仿真表明，随着CVC工作辊横移距离的增加，前张应力沿横向的差距增大；随着工作辊弯辊力的增加，前张应力沿横向的差距增大，且变化主要集中在板宽的边部；随着板宽的增加，前张应力沿横向的差距先减小后增大。     

PROFILE AND FLATNESS CONTROL SYSTEM IN 1 700 mm HOT STRIP MILLS OF ANSTEEL

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 μm 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 fiatness control system. In addition, schedule-free rolling is realized.     

Research and application of non-symmetrical roll bending control of cold rolling mill

The existing research of the flatness control for strip cold rolling mainly focuses on the calculation of the optimum adjustment of individual flatness actuator in accordance with the flatness deviation,which can be used for general flatness control.However,it does not work for some special rolling processes,such as the elimination of ultra single side edge-waves and the prevention of strip break due to tilting roll control overshooting.For the purpose of solving these problems,the influences of non-symmetrical work roll bending and intermediate roll bending on flatness control were analyzed by studying efficiencies of them.Moreover,impacts of two kinds of non-symmetrical roll bending control on the pressure distribution between rolls were studied theoretically.A non-symmetrical work roll bending model was developed by theoretical analysis in accordance with practical conditions.The model was applied to the revamp of a 1250 6-H reversible universal crown mill (UCM) cold mill.Theoretical study and practical applications show that the coordination utilization of the non-symmetrical work roll bending control and tilting roll control was effective in flatness control when there appeared bad strip single side edge waves,especially when the incoming strip was with a wedge shape.In addition,the risk of strip break due to tilting control overshooting could be reduced.Furthermore,the non-symmetrical roll bending control can reduce the extent of uneven distribution of pressure between rolls caused by intermediate roll shifting in flatness control and slow down roll wear.The non-symmetrical roll bending control technology has important theoretical and practical significance to better flatness control.     

LVC工作辊在超宽带钢热轧机的应用

分析了超宽带钢轧机的板形控制特性,指出其在板形控制方面的不足.为增加超宽带钢热轧机的板形调节能力,开发了线性变凸度(LVC)工作辊,实现板形调节与带钢宽度成线性关系,其板形控制性能优于CVC技术.建立了LVC工作辊的板形控制策略模型,在超宽带钢热轧机上实现了长期稳定应用.生产实绩表明,LVC工作辊可显著提高带钢的凸度控制精度,对凸度控制要求严的供冷轧料和凸度难控制的高强度管线钢,其凸度控制在50±18mm的比例可达96%以上.     

VC轧辊的承载特性研究

对控制压力与轧制力共同作用下的VC(variable crown)轧辊的承载特性进行了研究。基于所开发的VC轧辊系统,分析了辊缝形状和辊缝凸度与轧制力及控制压力的关系,提出了临界最大控制轧制力的概念。研究结果表明:当轧制力小于轧辊系统的最大临界控制轧制力时,其板形控制能力优于同规格的实心平辊;当控制压力较大且轧制力较小时,轧辊系统可以实现零凸度或负凸度的负载辊缝。     

Mechanics of roll edge contact in cold rolling of thin strip

Simulation of cold rolling of thin strip due to roll edge contact with oil lubrication was performed successfully using a developed influence function method. Roll edge contact and related surface roughness was discussed in this paper. The calculated rolling force, intermediate force and work roll edge contact force increase significantly when the reduction increases. The strip profile becomes poor with a higher reduction, and the calculated rolling forces are consistent with the measured values. A modified edge shape of work roll determined from the roll edge contact length and roll edge flattening value is helpful to reduce the work roll edge wear and to extend the work roll life. Surface roughness and asperity of the rolled strip are characterized by surface profilometer and atomic force microscope. The research shows that the surface roughness reduces with a higher reduction or rolling speed. The effect of the strip width on surface roughness is not significant.     

板型仪在冷连轧系统中的应用

某钢厂1420 mm冷连轧机组，采用板型仪作为轧钢AFC的板型控制系统，该系统不仅能实现轧制生产全过程中的闭环控制，而且可以通过对工作辊和中间辊的弯辊控制以及轧机压下、精细冷却和窜辊等控制手段有效改善板带的断面形状及平直度。     

宽带钢冷连轧机综合耦合模型的建立与分析

宽带钢冷连轧过程中,板形、板厚和张力控制之间存在着很强的耦合关系,相互影响对方的调节功效。为了进一步提高控制精度,进行解耦设计实现解耦控制是十分有效的手段,而其前提和基础就是冷连轧机综合耦合模型的建立和分析。首先,运用轧制理论对轧制过程中板形、板厚和张力控制的各种影响因素进行了系统的分析,然后考虑执行内环的动态特性建立冷连轧机综合耦合模型,以定量地描述轧制过程中辊缝、弯辊力、本架轧辊速度、前架轧辊速度和出口厚度、出口凸度、出入口张力之间的耦合影响关系。最后,基于Matlab/Simulink工具,采用此耦合模型对某冷连轧机末机架的耦合特性进行仿真分析,指出对其进行解耦控制的必要性。