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。     

冷连轧设定控制系统综合优化研究

基于现阶段冷轧板形精度要求的提高、板形控制技术的发展与智能控制技术的进步,在传统冷连轧负荷分配研究基础上,提出板形板厚张力设定控制系统综合优化计算方法。对板厚、张力进行兼顾板形偏差最小、弯辊裕量最优及负荷平衡的多目标优化设计,对工作辊弯辊、中间辊弯辊以沿带钢全宽板形偏差最小为目标进行优化设计。优化计算采用具有良好全局和局部寻优能力的三种群粒子群差分进化算法(Three-populations particle swarm optimization and differential evolution algorithm,Thr_PSODE)。现场应用结果表明,通过设定控制系统综合优化对轧制规程、张力制度以及各板形调控手段的优化配置,在兼顾多个优化目标的同时充分挖掘轧机的板形调控能力,实现了对复杂模态的高次板形缺陷的有效控制,具有重要的研究价值与应用前景。     

梅钢1420平整机组辊型及轧制工艺参数优化

针对梅钢1420双机架平整机组的板形问题,经过大量的现场试验与理论研究,充分结合平整机组的设备与工艺特点,以机组成品板形良好作为优化目标,对1#、2#机架工作辊与支撑辊辊型进行了优化设计,并在此基础上根据轧制工艺参数的特点分静态和动态两种形式对1#与2#机架轧制压力、1#与2#机架弯辊力、前张力、中张力以及后张力等7个关键轧制工艺参数进行了综合优化,取得了良好的使用效果,大大降低了现场板形的封闭率,具有进一步推广应用的价值。     

2400mm热轧机机架三维有限元分析

应用Abaqus有限元分析软件,采用三维线弹性分析方法对某大型铝轧厂2400mm热连轧精轧机机架进行了模拟,得出其应力和变形分布规律,进行强度和刚度分析,进而计算出机架的刚度,其结果不仅给机架的结构设计提供理论指导,而且对轧制规程的制定和板形控制具有实用价值.     

涟钢CSP热连轧机变接触支持辊辊形的研究

针对涟钢CSP热连轧机F2机架支持辊磨损不均,且出现的剥落问题,根据F2机架磨损辊形的特点及变接触技术思想,提出与工作辊辊形相匹配的支持辊新辊形VCR＋,采用二维变厚度有限元模型对新辊形的板形控制性能进行了分析,并且在F2机架上进行工业实验。通过仿真计算和试验结果表明,VCR＋辊形的板形控制性能均优于原辊形,自保持性能有了显著的提高,磨损及均匀性有了很大的改善。     

一个轧制单元内实时辊系综合凸度预测及应用

用有限元法在精确计算机械板凸度并在验证其计算结果有效性基础上,通过解析板形刚度理论,解析凸度遗传方程中的遗传系数,建立计算带钢的板凸度方程。利用现场实际生产工艺参数依次计算各架轧机出口带钢凸度并和末机架后凸度仪测量的板凸度值比较,预测热连轧机辊系综合凸度在一个轧制单元内的变化规律。预测结果通过对现场各机架大量的工作辊辊型测量数据经计算后得到验证,在一定工况条件下,预测的辊系综合凸度整体变化趋势和实际辊系凸度变化保持一致。这种预测方法避免了热连轧过程中为精确控制板凸度而计算各单个机架轧辊实时热、磨凸度变化所带来的复杂性,完成了一个轧制单元内实时辊系综合凸度预测值在各单个机架轧机上的凸度分配及应用。应用效果表明,现场带钢板凸度目标值在±10μm内的命中率由91%提高到97%,产品实物质量得到明显改善。所建模型与预测结果对板形理论研究和现场操作实践具有实际参考价值。     

扁钢热连轧立辊轧机横移装置的优化设计

机架横移装置是热连轧机精轧机组中立辊轧机的核心部件之一,其结构优劣对于精轧机充分发挥控制和改善板形能力,提高板带材平直度具有重要影响。如今,通过改进现有设备,提高产品质量已经成为各钢铁企业越来越主要的升级生产技术的手段。针对扁钢热连轧立辊精轧机中的机架横移装置进行受力分析和有限元校核,以优化结构,降低故障率,提高工作效率。     

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。     

四辊轧机非常态轧制时板形模型的研究

针对四辊轧机工作过程中可能出现的上下左右不对称问题,在大量的现场试验与理论研究的基础上,充分结合四辊轧机的设备与非常态轧制的工艺特点,从辊系弹性变形模型入手,充分考虑到四辊轧机非常态轧制过程中的上下与左右的不对称性,建立一套适合于四辊轧机非常态轧制时的板形模型,编制相应的板形分析与控制软件,利用该模型及软件不但可以定量预报出带材跑偏、不对称辊型、轧制中心线与轧辊中心线不重合、不对称弯辊、不对称窜辊等非常态因素单独或综合作用对轧机成品板形的影响,而且可以定量预报出对称弯辊、对称窜辊、倾辊等常态因素对成品板形的影响。该模型及软件已经被应用到梅钢1420双机架平整机组的板形分析与控制,有效地提高了机组的成品板形质量,板形封闭率从项目开展前的2.5%降低到目前的0.5%以内,给机组创造了较大的经济效益,具有进一步推广应用的价值。     

铝热连轧弯辊力建模与仿真

弯辊力是调节板形的重要手段,准确的弯辊力模型能够为轧制获得良好的板形。为了准确的预测铝热连轧弯辊力,以某厂1+4铝热连轧实际生产数据为样本,提出了支持向量机(SVM)弯辊力模型。由于SVM的精度及泛化能力依赖于参数选择,故将自由搜索算法(FS)运用到模型参数寻优过程,并分别与BP神经网络和粒子群(PSO)优化的SVM模型进行比较。仿真实验表明建立的FS-SVM模型参数优化速度快、结构简单并且具有较高的预报精度。     

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.     

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。     

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。     

小型四辊轧机工作辊水平位移对板形的影响

小型四辊轧机由于工作辊长径比较大且辊径较小而造成工作辊沿轧制方向很容易出现水平位移现象,常规四辊轧机板形计算模型不能满足出口板形的准确计算与预测,为此,充分结合小型四辊轧机的设备与工艺特点,建立了四辊轧机考虑工作辊水平位移时的板形模型;通过板形对比说明了该模型计算结果的准确性。在此基础上,具体分析了工作辊水平位移产生的规律以及在考虑工作辊水平位移时弯辊力对板形控制的影响,并将该模型应用到某钢厂650可逆四辊轧机机组,开发了650可逆四辊轧机工作辊水平位移对板形影响分析软件,有效地解决了以往板形计算误差大的问题,实现了对出口板形的准确计算与预测,大大提高了板形控制精度。     

热轧辊缝调整机构的布置形式比较

从热连轧机、中厚板可逆轧机以及宽厚板可逆轧机3种轧机类型出发,介绍热轧四辊轧机中参与辊缝调整的设备组成、布置形式及比较3种配置方式的优点和不足。     

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.     

1200WS轧机结构参数设计

WS轧机是目前生产优质板材产品较为理想的先进设备之一,它采用了一个工作辊可移动和工作辊弯辊技术,可以有效的改善和提高板形精度.通过对设计方案的选择,力能参数及其它重要参数的计算,使轧机生产出来的产品达到了国家标准和设计要求.并且同时进行了结构设计和轧辊零件的设计,使结构更加合理,并且突出了WS四辊可逆式冷轧机的作用     

Fuzzy algorithm for calculating roll speed variation based on roll separating force in hot rolling

Thickness control of hot-rolled strips has become an important issue in recent years because of the need for improving the quality of the hot-rolled strip. For this purpose, various thickness control systems such as finishing mill set-up (FSU), automatic gauge control (AGC), and looper control system, have been developed at steel works. Although these systems have greatly improved the quality of the strip thickness, there still exists a small amount of thickness deviation. It is difficult to adequately control by applying conventional thickness control techniques since hot rolling process is a highly nonlinear system in which many process parameters are coupled. In this study, a fuzzy algorithm to calculate the roll speed variations was developed in order to improve the thickness uniformity of hot-rolled strips. Since the strip thickness is mostly affected by the magnitude of roll separating force depending on the roll speed, the strip thickness deviation between the desired and actual thicknesses can be reduced by controlling roll speed. In order to carry out this investigation, slab analysis was carried out to determine the relation between roll separating force and roll speed for various process parameters such as roll speed, reduction ratio, strip entry thickness, and front and back tensions. From the production data, the effective stress-strain rate relations of the materials used in slab analyses were acquired. Based on the analytical results, the relation between roll separating force and roll speed was approximated by a log function. A fuzzy algorithm was developed to determine variations in roll speed according to variations of roll separating force, depending on various ranges of rolling temperature, reduction ratio, front and back tensions, and strip thickness. In addition, simulations to predict roll speed variations for a small amount of thickness deviation were carried out at continuous finishing mills consisting of seven stands and the calculated roll speed variations were found to be reasonable. Thus, the developed fuzzy algorithm might be useful in reducing the thickness deviation in the actual hot rolling mills.     

Energy conservation in stainless steel cold rolling applications

In order to predict the performance of rolling oils in actual production mills, from tests in laboratory mills, the influence of various factors, such as shape factors work roll diameter (D), strip thickness (h₁), operating conditions (reduction rate (r), peripheral velocity of roll (U₀), strip velocity (U₁)) and kinematic viscosity of the rolling oil (υ₀) was investigated. A parameter RLI (Rolling Lubrication Index = u₀(U₀+U₁)(1−r)(D/2h₁.r)^½) was found to be useful in predicting lubricating conditions in actual production mill applications. The coefficients of friction of mineral oils, some synthetic hydrocarbons including polybutene, and several kinds of additives were obtained from laboratory mills under the same condition of RLI value as that for finish rolling in actual production mills. With hydrocarbons, paraffins showed the lowest coefficient offriction, while aromatics exhibited a higher coefficient of friction, with naphthenes showing the highest. A high-quality rolling oil was formulated using a combination of ester and paraffinic mineral oil. It is observed that this new oil can save 14% of energy consumed by a laboratory mill compared with conventional rolling oils. In production mills, nearly the same energy conservation level can be achieved.