Research and Development Trend of Shape Control for Cold Rolling Strip

Shape is an important quality index of cold rolling strip. Up to now, many problems in the shape control domain have not been solved satisfactorily, and a review on the research progress in the shape control domain can help to seek new breakthrough directions. In the past 10 years, researches and applications of shape control models, shape control means, shape detection technology, and shape con- trol system have achieved significant progress. In the aspect of shape control models, the researches in the past improve the accuracy, speed and robustness of the models. The intelligentization of shape control models should be strengthened in the future. In the aspect of the shape control means, the researches in the past focus on the roll opti- mization, mill type selection, process optimization, local strip shape control, edge drop control, and so on. In the future, more attention should be paid to the coordination control of both strip shape and other quality indexes, and the refinement of control objective should be strengthened. In the aspects of shape detection technology and shape control system, some new types of shape detection meters and shape control systems are developed and have successfully indus- trial applications. In the future, the standardization of shape detection technology and shape control system should be promoted to solve the problem of compatibility. In general,the four expected development trends of shape control for cold roiling strip in the future are intelligentization, coordi- nation, refinement, and standardization. The proposed research provides new breakthrough directions for improv- ing shape quality.

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 a1700 mm single-stand temper mill. Some critical problems such as the deviation of work roll contourcaused by grinding and wear, the effectiveness of work roll bending were discussed. Using a finiteelement 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 somespecial features of flatness control in the temper mill: during temper rolling, roll deformation isslight due to small rolling load, and the loaded roll gap profile mainly depends on work rollcontour, while the backup roll has a little effect on gap crown; the effect of bending force ongauge can not be ignored due to the coupling between flatness control and gauge control. A new rollcontour 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 workroll bender, higher rolling stability, better strip profile and flatness quality.

Study and application of crown feedback control in hot strip rolling

Crown feedback control is one part of the automatic shape control （ASC） system. On the basis of large simulation researches conducted, a linear crown feedback control model was put forward and applied in actual strip rolling. According to its successful op- eration in the ASP 1700 hot strip mill of Angang Group for one year and also from the statistical results of several crown measurements, it can be definitely said that this control model is highly effective and shows stable performance. The control effectiveness of different gauges of strips with the feedback control is found to increase by 10%-30% compared with that without feedback control.

Industrial shape detecting system of cold rolling strip

A high-precision shape detecting system of cold rolling strip is developed to meet industrial application,which mainly consists of the shape detecting roller,the collecting ring,the digital signal processing(DSP) shape signal processing board and the shape control model.Based on the shape detecting principle,the shape detecting roller is designed with a new integral structure for improving the precision of shape detecting and avoiding scratching strip surface.Based on the DSP technology,the DSP shape signal processing circuit board is designed and embedded in the shape detecting system for the reliability and stability of shape signal processing.The shape detecting system was successfully used in Angang 1 250 mm HC 6-high reversible cold rolling mill.The precision of shape detecting is 0.2 I and the shape deviation is controlled within 6 I after the close loop shape control is input.

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.

柳钢1450热轧线粗轧板形控制方法探究

柳钢1450热连轧生产线精轧工序头尾穿带稳定性极大程度受到粗轧中间坯板形影响,偶尔发生因来料板形差引发的楔形大、轧破、甩尾等现象。特此结合粗轧区域设备特性探索粗轧板形控制方法,对关键设备采取针对性改进措施,如设备对中精度、压下系统精度、装备配合间隙等,并开发投用板形调整功能适配工艺参数优化,应用于实际生产并取得明显效果。

基于改进斑点鬣狗算法的热轧带钢负荷分配智能优化

针对热连轧过程中由于负荷分配不均匀导致板形控制效果不佳的问题,以传统的轧制机理为基础建立负荷分配均匀、板形良好的目标函数,分别采用斑点鬣狗算法和改进斑点鬣狗算法进行单目标和双目标的负荷分配的优化求解。结果表明,改进斑点鬣狗算法将末机架的相对凸度差从0.000 834 5降低到0.000 014 83和-0.000 026 34,且在允许的范围内,上游机架负荷分配合理,充分发挥了轧机的轧制能力。

有色金属板带箔边部板形控制及算法

针对宽幅有色金属板带箔材边部板形控制问题,提出一种有色金属板带箔边部板形控制方案及算法,能有效改善带材边部所在工作辊辊形,实现带材边部板形有效可控。

平整机组张力综合优化控制技术

针对某钢厂平整机组轧制过程中出现的带钢打滑以及板形质量较差的问题,从打滑的防治、产品的机械性能与板形的控制等出发,首先通过轧制压力模型将轧制压力和张力联系起来,然后通过板形模型、前张力横向分布模型和打滑模型将板形、打滑概率、伸长率以及前后张力建立联系,最后以不出现打滑现象和成品带钢板形质量最佳为优化目标,建立了一套张力综合优化函数,该函数的优化结果即表示在不发生打滑和伸长率允许误差的范围内,成品带钢板形值最好时的张力设定值,从而形成一套平整机组的张力优化设定技术,并编制出相应的张力综合优化设定软件,可以实现对特定规格、钢种的带钢优化设定出相应的前后张力值。将优化结果应用到现场生产实际,结果表明,使用优化后的张力在轧制过程中未出现打滑现象,且成品带钢的板形质量得到明显改善,提高了机组生产效益。

冷轧平整机板形控制研究

对某厂冷轧平整机的轧制生产过程进行分析,利用有限元仿真模型技术对板形特征调控进行仿真分析,深入研究平整机辊形、轧制力以及生产带钢宽度对生产带钢板形的影响,由仿真模型结果展现出板形问题的机理,以此为基础提出冷轧平整机板形控制措施。通过实际应用对比发现,改进后,带钢生产时板形问题出现概率降低59%。

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

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.

热带钢轧机板形综合控制技术开发

为了改善热带钢轧机的板形控制性能、提高产品的板形质量、降低生产消耗,针对工作辊可轴向窜动的热带钢轧机,在大量有限元模拟基础上开发了特殊的工作辊辊形技术和支持辊辊形技术及相应的板形控制模型,包括过程控制系统(L2级)的板形设定控制模型和基础自动化系统(L1级)的弯辊力前馈控制模型、凸度反馈控制模型及平坦度反馈控制模型.在经历离线模型建立、在线编程和调试等诸多复杂过程后,辊形技术及板形控制模型在工业宽带钢热轧机上进行了长期、稳定的应用.生产实践表明,采用这些板形控制技术后,凸度偏差控制在±18μm的比例超过93%,平坦度偏差控制在±25IU的比例超过94%,同时实现了自由规程轧制.

HC轧机板形板凸度控制策略的研究

采用开发的基于条元法冷轧带材板形分析与控制仿真软件 ,分析了 90 0 m m HC轧机板形控制特性 ,确定出该轧机的板形板凸度控制策略。经工业应用表明 ,该控制策略应用于 HC轧机板形控制过程中 ,提高了轧后带材板形精度 。

冷连轧机带钢单锥度辊边降控制

针对冷连轧机带钢边降板形控制问题,研究了单锥度工作辊的辊形构成、特点和控制策略,建立有限元模型对比分析了单锥度、常规凸度和SmartCrown工作辊板形控制性能,并结合大型工业轧机调试实验分析了该板形控制新技术在实际生产中的使用情况.结果表明,应用单锥度辊可以有效降低带钢边降,减小带钢总凸度.

冷轧平整机板形问题的特点及对策

对某冷轧厂 170 0 m m单机架平整机的板形问题进行了综合研究 ,发现该轧机在辊形加工、轧辊磨损及弯辊使用等方面存在的问题 ,并通过有限元模型研究了辊形对板形的作用 ,分析了平整上弯辊对板厚的影响 ,指出平整机板形问题的特殊性。针对平整板形的设备工艺特点 ,提出了新的辊形配置方案并正式投入生产。结果表明 ,改进后的辊形配置对降低弯辊调整量、改善板形、提高生产过程稳定性效果显著。

板形控制与热轧带钢自由规程轧制

板形是热轧带钢的重要质量指标。自由规程轧制是带钢热轧中实现柔性生产组织和最高生产效率的必由之路。热轧工作辊表面严重不均匀磨损 ,导致承载辊缝形状畸变和“批量同宽轧制”或“大逆宽轧制”时带钢板形失控 ,进而制约了自由规程轧制。自由规程轧制问题本质上是板形控制问题。为了实现自由规程轧制需减少磨损量、均匀化磨损分布或开发特殊的板形控制技术。

冷连轧机变接触支承辊板形控制性能研究与应用

通过现场跟踪测试和生产实践发现武钢1700冷连轧机组“酸轧联机”改造工程中存在常规凸度辊形配置方案不合理,由此引起了薄规格轧制的工作辊“压肩”现象和轧制过程欠稳定导致成品板形质量欠佳等问题。采用二维变厚度有限元方法建立辊系弹性变形仿真模型,研制了酸轧联机条件下的VCR变接触支承辊,经过工业轧机现场轧制已成功投入1700冷连轧机实际应用。现场应用表明:改善了轧机板形调控性能,提高了带钢板形质量,增强了薄规格品种轧制能力,支承辊辊形自保持性较好。

1700mm冷轧带钢轧机板形控制能力研究

带钢的板形包括凸度、边部减薄和平坦度 3个要素。采用轧制过程的跟踪纪录、板形控制过程的数据分析和轧件取样测量的综合评价方法分析了 1 70 0mm冷连轧机的板形控制能力 。

热轧薄带钢板形影响因素的离线模拟分析

利用自主开发的离线模拟分析软件，结合唐钢超薄带钢生产现场各种工艺条件，对影响板形的因素进行了定量分析。结果表明：F4、F5轧机弯辊力对最终板凸度的影响大于F1～F3轧机；带材厚度对弯辊力作用效果的影响不明显。不同机架的PC角变化对板凸度的影响基本相同，随着PC角的增加，最终板凸度减小，且PC角越大，减小的趋势增强。F1～F5轧机中任一轧机轧制力的增大，最终板凸度近似成线性增加；下游机架轧制力的变化对板凸度的影响大于上游机架；轧制力的变化更容易导致薄规格产品产生板形不良。

济钢1700mm热带钢轧机的板形设定控制模型

济钢1700 mm热连轧是新建投产的宽带钢生产线,其F2—F6精轧机组装备有工作辊弯辊和窜辊技术。针对这种典型机型,在大量有限元模拟计算的基础上,开发了相应的板形设定控制模型,包括工作辊综合辊形(初始辊形、磨损辊形和热辊形之和)计算模型、支承辊综合辊形计算模型、窜辊设定计算模型和弯辊力设定计算模型等。在经历了系统设计、程序编写、离线调试、在线调试后,板形设定控制模型投入稳定运行,所有考核规格的凸度控制精度超过96%。在同宽轧制长度超过70 km的轧制单位内,各机架弯辊力设定结果能够自动适应带钢厚度和钢种的变化,且凸度控制精度超过95%。