Optimization of Roll Shifting Strategy of Alternately Rolling in Hot Strip Mill

 An optimization solution to roll shifting strategy for alternately rolling campaign is presented. All the strips in a rolling campaign are divided into narrow strips and wide ones, and shifting position of narrow strips is obtained by the recursive method, and then shifting position of wide strips is optimized by NSGA-II which is a multi-objective genetic algorithm. For wide strips, a multi-objective optimization model of roll shifting strategy is proposed, which takes 3 wear contour factors including edge smoothness, body smoothness and edge drop as optimization objectives. The Pareto optimal front of roll shifting strategy can be gained quickly by NSGA-II, which suggests a series of alternative solutions to roll shifting strategy. Analysis shows that the conflict exists among the 3 objectives. The final optimal solution is selected from the Pareto optimal solutions by the weighted-sum decision-making method. Industrial production proves the validity of the solution, and it can improve strip profile of alternately rolling, reduce strip edge wave, and extend the rolling miles of rolling campaigns.     

热连轧机负荷分配优化计算策略

提出一种带钢热连轧精轧机组负荷分配的优化计算策略,采用多目标优化算法离线计算确定精轧各机架的轧制力分配系数,采用"压下模式+轧制力模式"相结合的方式实现负荷分配在线计算。为了确定各精轧机架的轧制力分配系数,建立兼顾轧制功率最小、负荷均衡与板形良好的负荷分配多目标优化模型;为了实现负荷分配在线计算,根据压下模式负荷分配计算确定厚度分配的初始值,根据CLAD算法进行轧制力模式负荷分配迭代计算,最后采用压下模式分配计算确定的压下率分布范围对轧制力模式分配结果进行限幅处理。新方法已成功应用于梅钢1 780mm热连轧生产线,在线应用表明该方法可以有效减少操作工干预,提高带钢精轧过程的轧制稳定性。     

Optimization of Temperature and Force Adaptation Algorithm in Hot Strip Mill

Abstract： In the hot strip rolling control system, the temperature distribution and deformation resistance are the main parameters affecting prediction of rolling force. In order to improve the model prediction precision, an optimiza- tion algorithm based on objective function was put forward, in which the penalty function index was adopted. During the adaptation process, the temperature distribution and deformation resistance were taken as the optimized parame ters, and the Nelder-Mead simplex algorithm was used to search the optimal solution of the objective function. Fur thermore, the temperature adaptation and force adaptation were solved simultaneously. Application results show that the method can improve the accuracy of the rolling force model obviously, and it can meet the demand of the indus trial production and has a good application prospect.     

热轧带钢窜辊策略与综合辊型的研究及应用

 研究了热轧带钢窜辊策略对轧辊综合辊型的影响,建立了窜辊策略的多目标优化模型。综合考虑轧辊磨损、热凸度和原始辊型,仿真研究窜辊策略对轧辊综合辊型的影响,提出中部平滑和边部平滑2个评价指标;以所有带钢的平均中部平滑指标和平均边部平滑指标为优化目标,带精英策略的非支配排序遗传算法（NSGA-Ⅱ）为优化算法,建立基于轧辊综合辊型仿真的窜辊策略的多目标优化模型。仿真计算得到窜辊分散轧辊磨损和热凸度的效果,发现变行程窜辊能获得无局部猫耳的“餐碟型”综合辊型,有利于实现自由规程轧制。工业生产验证了优化窜辊策略和相关模型的有效性,显著改善了板形质量,延长了轧制计划公里数。     

五机架冷连轧机的负荷分配计算

针对八辊五机架全连续冷连轧机在轧制过程中的特点,在综合考虑了轧机产量和产品质量的前提下,用多目标优化问题的求解方法对多辊冷连轧机的轧制策略进行优化,确定各机架的负荷和待轧带钢的目标厚度,并开发了河北中钢1 250 mm八辊五机架全连续冷连轧机的负荷分配计算程序。通过现场实例证明,该方法精度高、速度快,可满足在线控制需求,是一种适合多辊全连续冷连轧机的负荷分配方法。     

精轧负荷分配自动实现技术及应用

运用KDD技术对热轧带钢生产中过程机大量历史数据和积累了多年的轧制信息(包括轧制负荷相关的信息)进行预处理和数据挖掘,并结合相应的理论知识,开发了适合现场生产的负荷分配模型.该模型能实施多种功能,并在实践中取得成功应用,实现了负荷分配的自动设定,形成了规范的负荷分配制度.同时给出了负荷分配模型的优化方法.     

Generalized Shape and Gauge Decoupling Load Distribution Optimization Based on IGA for Tandem Cold Mill

 Load distribution is the foundation of shape control and gauge control, in which it is necessary to take into account the shape control ability of TCM (tandem cold mill) for strip shape and gauge quality. First, the objective function of generalized shape and gauge decoupling load distribution optimization was established, which considered the rolling force characteristics of the first and last stands in TCM, the relative power, and the TCM shape control ability. Then, IGA (immune genetic algorithm) was used to accomplish this multi objective load distribution optimization for TCM. After simulation and comparison with the practical load distribution strategy in one tandem cold mill, generalized shape and gauge decoupling load distribution optimization on the basis of IGA approved good ability of optimizing shape control and gauge control simultaneously.     

兼顾板形的单机架UCM冷轧机负荷分配的优化方法

负荷分配是板厚控制和板形控制的基础,为了保证成品带钢的板形板厚质量,需要在负荷中考虑板形调节能力。综合考虑了单机架轧制各道次轧制压力和板形调节能力,建立了基于粒子群算法的单机架冷轧负荷分配优化数学模型,并利用该算法实现了单机架冷轧机多目标负荷分配优化。采用优化后的轧制规范组织实际生产应用,结果表明该优化模型很好地兼顾了板形控制和板厚控制,达到了良好的应用效果。     

Development of New Generation Cooling Control System After Rolling in Hot Rolled Strip Based on UFC

 Ultra-fast cooling (UFC) is an advanced technology in hot rolling field. Through this technology, great changes on the run-out table are produced in the strip cooling process. In order to adapt to these changes, a new generation of hot strip cooling control system after rolling was developed based on the UFC basic principle. The system can not only accomplish temperature of UFC delivery side, coiling temperature, cooling rate, etc, and multi-objective accuracy control, but also offer more flexibility and new attractive possibilities in terms of cooling pattern on the run-out table, which could be of prime importance for the production of some difficult steels. In addition, through the time-velocity-distance (TVD) profile prediction combined with speed feed-forward control and coiling temperature feedback control, the coiling temperature control precision can be effectively improved during accelerative rolling in the system. At present, the system has been successfully used in the conventional strip production line and CSP short process production line, and its application effect is perfect.     

Multi-Objective Optimization for Tandem Cold Rolling Schedule

 Based on rolling feature of continuous tandem cold rolling mill, such as multi-variable, strong coupling, non-linear, analyze and set the equal relative load, preventing slippage and profile well as the multi-objective optimization goal, BP neural network with self-learning function is adopted to replace traditional rolling force models and then Levenberg-Marquardt algorithm is adopted to predict the rolling force. Then use multi-objective fuzzy theory to solve the problem of multi-objective optimization of tandem cold rolling schedule. With the example of 1370mm tandem cold rolling, the rolling schedule of the common rolling, the single-object optimization design and the multi-objective fuzzy optimization design are compared with each other, optimization result shows the proposed optimization method decreases the value of three objective functions simultaneous. The performance of the optimal rolling schedule is satisfying and it is promising.     

基于改进差分进化算法的带钢冷连轧负荷分配

 为了更加合理地制定冷连轧轧制规程,选取打滑因子、等功率裕度和最小能耗作为目标函数,采用改进的差分进化算法求解Pareto前沿,减少了冗余的寻优代数、缩短了优化时间。以求解出的Pareto前沿为选择池,基于不同的偏好因子选择出不同的负荷分配方法,满足不同工况下的要求。仿真结果表明,该算法可以快速均匀地覆盖Pareto前沿,产生偏重于不同目标的负荷分配规则。优化规程与原规程相比,降低了打滑现象出现的概率,减小了轧制功率。     

基于遗传算法的PP及冷连轧轧制规程多目标优化

 针对多目标优化算法中综合目标函数权值难以确定的问题,通过对偏好的数学量化,采用数值分析的方法,构造了6种不同的偏好函数,建立了物理规划（physical programming）数学模型,然后以遗传算法为寻优工具,实现一种更加灵活更加适合于工程技术人员的交互式多目标优化算法。结合某冷轧厂实际的轧制规程优化过程,选取等功率裕量、轧制总能耗及各机架打滑因子为目标函数,运用基于遗传算法的PP进行优化计算。结果表明,优化后的轧制规程很好地实现了各机架等功率负荷分配,降低了打滑出现的概率,大大提高了板材表面质量和成品成材率。     

基于多目标遗传算法的工作辊温度场计算与分析

等效换热系数是热连轧机工作辊温度场仿真模型的核心输入参数,多采用遗传算法优化得到,某1800 mm 热连轧机存在品种、规格交替轧制,等效换热系数的准确计算比较困难.选取多组典型工艺条件下的工作辊下机后表面温度作为优化目标,采用多目标遗传算法进行优化,并通过改变遗传算子有效避免了算法早熟及局部收敛等问题,获取了具有较强适应性的等效换热系数.仿真和实测数据的对比结果证明了优化模型的可靠性.利用仿真模型分析了主要工艺参数对工作辊热凸度的影响,并提出同宽交替时,工作辊热凸度随轧制进程呈指数变化,而在品种、规格交替编排轧制工艺下相邻带钢轧制时工作辊热凸度存在6-21.8μm 的波动,且随轧制进程趋于稳定.      

Development of Mathematical Model for Control Wear in Backup Roll for Hot Strip Mill

The precision of strip flatness depends on several factors; wear of rolls is one of the main variables that have influence on the surface quality of the strip. The wear of the roils represents a complex friction condition, sometimes the wear in the backup roll is not analyzed because the strip is not in contact with the backup roll; however, after several campaigns of rolling, the wear in the backup roll becomes dangerous because the pressure distribution is not uniform. Investigation of mechanism of the surface deterioration of the backup roll for the hot strip rolling is very important for the development of the automatic strip shape control system used in hot strip mills. A mathematical model is developed considering the Hertzian pressure distribution between two cylinders with parallel axes. It is used in real time for calculating the wear in the backup roll and in this manner take deci- sions for preventing finished product reworking or damage of equipments, which result in accidents caused by excessive wear in the backup rolls.     

1580热连轧机减少轧件温降措施的研究

宝钢1580热连轧机采取了保温罩、较厚的粗轧出口中间坯、先进的粗轧道次负荷分配方式等措施，以减少轧制过程温降。其温度计算数学模型计算精度较高。本文介绍了该轧机的温度数学模型，分析轧制过程中的轧件温降，较详细地介绍其减少轧件温降的措施。     

冷连轧负荷分配优化方法

 冷连轧负荷分配最优化对于提高冷轧带钢的产量和质量具有至关重要的作用。在研究蚁群算法优缺点的基础上,首次提出了将遗传算法和蚁群算法相融合的GA ACA优化算法应用于冷连轧负荷分配的优化。该算法采用遗传算法生成初始负荷分配,利用蚁群算法求取最优化分配结果,优势互补,具有计算精度高、速度快等优点,适合于负荷分配的在线应用。试验对比数据证明了该方法的有效性,为冷连轧负荷分配的优化提供了一种新的方法。     

马钢CSP热轧PFC板形模型的分析与应用

利用有限元分析软件ANSYS对轧机承载辊缝变形的仿真,分析轧机轧制力、弯辊力及工作辊窜辊对承载辊缝的凸度影响程度,结合现场机架间带钢的浪形,优化二级板形模型设定参数,实现轧机稳定轧制。实践证明,人工修正轧机负荷分配以及CVC轧辊位置,可更好地控制前机架比例凸度,满足后机架间平直度目标的要求,从而提高板凸度的命中率及轧机轧制的稳定性。     

板形设定模型参数优化与控制技术应用

 板形设定模型是整个板形自动控制系统中非常重要的一部分,决定着带钢头部板形的控制精度。板形精度既为热轧带钢的一项重要质量指标,又为衡量产品市场竞争力的主要因素。板形控制是带钢热轧的核心技术,为目前轧制技术研究开发的热点。阐述了鞍钢1780线PC轧机板形设定模型功能和构成,对轧辊热凸度模型参数进行了优化,在模型自学习中对各机架给予适量的平直度及凸度反馈,从而提高了板形设定模型精度。由于实际轧制过程的非线性、时变性,传统PID的控制已近极限,为进一步提高控制品质,板带平直度反馈采用非线性PID控制策略,其参数整定范围较宽,易于工程实现。通过对现场大量的轧制数据统计,在应用模型参数优化程序后,热轧板的平直度与凸度的头部命中率有了一定的提高。     

基于CF-PSO-SVM的冷连轧非稳态工作辊弯辊模型优化

 板形质量是冷轧带钢重要的技术质量指标,同时工作辊弯辊是改善冷轧带钢板形质量的最有效的控制手段之一。冷连轧机组在高速稳定的轧制过程中板形控制精度能够达到较高的水平,但在升降速非稳态的轧制过程中板形控制效果非常不理想,这也成为制约冷轧带钢产品质量的不利因素。为了提高冷连轧机在升降速非稳态轧制过程中带钢板形的控制精度,在深入研究了冷连轧弯辊力设定原理的基础上,利用智能算法和包括出入口带钢厚度、机架间口张力、轧制速度、中间辊窜辊、带钢宽度、轧辊倾斜以及轧制力等现场实际轧制大数据样本,提出了一种基于粒子群算法优化支持向量机的工作辊弯辊力预测模型。同时阐明了粒子群优化算法和支持向量机的基本原理,引入压缩因子的概念,提升了粒子群算法参数寻优的效率,选取冷连轧机组五机架为研究对象,利用拉依达准则对轧制数据样本进行处理,通过平均绝对误差、均方差误差和平均绝对误差百分比等评价指标对比预测模型的性能。结果表明,改进的预测模型具有良好的模型预测性能和泛化能力,同时根据实际生产数据样本,回归出基于轧制速度和辊间弹性系数的弯辊力缝补偿模型,并验证了模型的有效性,模型的投入降低了板形控制系统的负荷,改善了非稳态轧制过程中的板形控制精度,产品头尾部的质量合格率提高了5.1%。