自由程序轧制中轧辊横移与负荷分配的建模与优化研究

发布时间：2018-03-08 23:22

本文选题：热轧带钢　切入点：自由程序轧制　出处：《东北大学》2013年博士论文　论文类型：学位论文

【摘要】：进入工业社会以来,钢铁一直是人类最重要的基础原材料。目前,中国钢铁销售额约占全国GDP的8%,年产量约占全球总产量的50%,是我国最重要的支柱产业之一。但是,当前钢铁生产的利润微薄,降低制造成本成为钢铁企业生死存亡的关键所在。与此同时,用户需求越来越多样化,对产品品种、规格、质量的要求也越来越严。于是,能同时满足低成本和多样化要求的柔性化生产模式,成为钢铁企业的必然选择。在这种背景下,自由程序轧制技术(Schedule-Free Rolling, SFR)应运而生。SFR是带钢热轧中实现柔性生产组织的有效途径,它是指在一个换辊周期内,钢种、厚度、宽度几乎可以不受限制地自由过渡的轧制技术,能有效提高生产组织的自由度、降低生产成本。但是,受制于硬件设备条件和优化控制技术等因素,SFR目前在国内并未得到普遍推广。近年,随着热轧设备不断进步,国内部分热轧生产线开始具备实施SFR的设备条件,但优化控制技术的缺失反而成为制约SFR实施的瓶颈。SFR优化控制技术的困难在于：一是过程建模复杂：优化目标的精度要求为微米级,且受到轧制规格、工艺参数、设备状态等众多因素的影响；二是优化算法困难,SFR问题是多目标优化问题,计算过程非常复杂、耗时较长,难以用于实时控制。近年来,随着计算机性能的不断提升,使得对SFR的综合优化成为可能。结合宝钢1880热轧在SFR实施过程中存在的问题,本文进行了轧辊横移与负荷分配的建模与优化研究。通过研发SFR优化控制技术,克服轧制过程中不断增长变化的局部不均匀轧辊磨损与热凸度,保持精轧过程的轧制稳定性。主要研究内容及进展如下：1、在对轧辊磨损影响因素进行详细分析的基础上,采用“切片法”,建立考虑横移影响的轧辊磨损模型。采用逐步累计一叠加方法,对一个换辊周期内的轧辊磨损进行分析计算,发现实施轧辊横移后,轧辊磨损在带钢宽度方向趋于均匀,消除了轧件边端部的局部严重磨损造成的猫耳现象,有利于实施自由程序轧制。2、通过对轧辊温度场的数值模拟,建立高精度的轧辊热变形模型。考虑轧辊横移对轧辊热凸度的影响,提出模拟轧辊温度场PR格式的差分方法,指出轧件对轧辊温度场的影响存在“浅层效应”。对一个换辊周期内的轧辊热变形进行数值模拟,发现实施轧辊横移后,轧辊热膨胀的范围向辊身边部区域扩展,起到分散热凸度作用,使热辊型曲线更为光滑平缓。3、提出轧辊横移策略的多目标优化方法。开发基于分解的多目标差分进化算法(MODE/D),它使用差分进化算法代替遗传算法作为搜索引擎；提出变行程横移策略及其递推算法,通过横移步长、横移行程等决策变量来控制横移策略；通过数值模拟,分析横移策略对轧辊综合辊型的影响,给出两个平滑指标,用来评价横移对轧件接触部位辊缝形状的影响,以轧制计划带钢的平均边部平滑指标、平均中部平滑指标为目标函数,建立横移策略的多目标优化模型。在此基础上,提出交叉轧制横移策略的两阶段优化法。4、提出精轧负荷分配的多目标优化方法。开发高精度轧制力与轧制力矩的一体化模型,为负荷分配计算提供力能参数；提出轧制力模式负荷分配的CLAD算法,用于在线实现负荷分配计算；提出确定负荷分配系数的多目标优化模型,考虑能耗最小、负荷均衡和板形良好等优化目标,分析了不同目标间的矛盾关系。本文的研究内容,为轧辊横移策略与精轧负荷分配的优化设计提供了理论依据,同时面向自由程序轧制的在线控制,具有很强的实用性。相关成果应用到宝钢1880热连轧机组,大幅度拓展产线的自由轧制能力,同宽轧制长度从30km提高到60kmm,集批轧制总长度从70公里提高到100公里,实现复杂、难轧产品在大生产条件下的自由轧制。
[Abstract]:Since entering the industrial society, human based steel has always been the most important raw material. At present, Chinese steel sales accounted for about 8% of GDP, the annual output accounts for about 50% of the world's total output, is one of the most important pillar industry in China. However, the meager profits of the current steel production, reduce the manufacturing cost has become the key to steel the enterprise of vital importance. At the same time, more and more diversified customer needs, specifications of product variety, quality requirements are increasingly strict. So, the flexible production mode can meet the requirement of low cost and versatility, has become the inevitable choice of the iron and steel enterprises. In this context, schedule free rolling technology (Schedule-Free Rolling SFR) the.SFR came into being is a effective way to realize the flexible production organization of hot strip rolling, it refers to a roll changing period, steel grade, thickness, width is almost unrestricted free transition The rolling technology, can effectively improve the production organization degree of freedom, reduce the production cost. However, limited by hardware equipment and optimal control technology and other factors, SFR currently has not been popularized in China. In recent years, with the continuous progress of hot rolling equipment, the domestic part of the hot production line started with the implementation of SFR equipment, but optimization lack of control technology has been the bottleneck of the SFR implementation of the bottleneck of.SFR optimization control technology is difficult: it is a complex process modeling: optimization accuracy requirements for micron level, and by the rolling specifications, process parameters, many factors affecting the equipment state; two is to optimize the algorithm difficult SFR problem is a multi-objective optimization problem and the calculation process is very complex, time-consuming and difficult for real-time control. In recent years, with the continuous improvement of computer performance, the integrated optimization of SFR with possible. Baosteel 1880 hot problems in the implementation process in SFR, this paper carried out research on Modeling and optimization of roll shifting and load distribution. Through the research of SFR optimization control technology, overcome the growing changes in the rolling process of uneven roll wear and thermal crown, maintain the stability of rolling rolling process. The main research contents and progress are as follows 1, based on detailed analysis of influencing factors on roll wear, with "slice method", the establishment of roll wear model considering the influence. By gradually shifting the cumulative superposition, for a change in the period of roll roll wear is analyzed and found that the implementation of roll shifting, roll wear becomes even in strip the width of the edge and eliminate the ears at the end of the phenomenon of local severe wear caused, is conducive to the implementation of SFR.2, through the simulation of roll temperature field value, The establishment of high precision roll thermal deformation model. Considering the influence of roll shifting on the roll thermal crown, is proposed to simulate the temperature field of roller PR format difference method, pointed out the influence of workpiece on the temperature field of roller are "shallow effect. A change of thermal roll period deformation numerical simulation, carried out roll shifting, the thermal expansion of the scope of the roll to roll around the region, have dispersed thermal crown, the heat roller type curve is more smooth and flat.3, puts forward a multi-objective optimization approach for roll shifting strategy. The development of multi target decomposition based on differential evolution algorithm (MODE/D), which uses differential evolution the algorithm instead of genetic algorithm as the search engine; the variable stroke shifting strategy and its recursive algorithm, by traversing step, traversing stroke as decision variables to control the shifting strategy; through numerical simulation, analysis of comprehensive roll shifting strategy Influence of roll, given two smooth index used to evaluate the effect of the sliding contact part of the roll gap shape, with average edge smoothing index of strip rolling plan, the average central smoothing criterion as the objective function, a multi-objective optimization model for rollshifting strategy. On this basis, put forward.4 two phase optimization method of intersection roll shifting strategy, put forward the multi-objective optimization method of load distribution. The integration model of rolling development of high precision of rolling force and torque, provide mechanical parameters for load distribution calculation of rolling force model; CLAD algorithm is used to realize the load distribution, load distribution line calculation; multi-objective optimization model is proposed to determine the load distribution coefficient. Considering the minimum energy consumption, load balancing and good shape optimization goal, analyzes the contradictory relationship between the different objectives. The research content of this paper, for the roll shifting strategy and finishing To provide a theoretical basis for the optimal design of load distribution, online control at the same time for schedule free rolling, have very strong practicability. The relevant results are applied to Baosteel 1880 hot rolling mill, free rolling ability greatly expand the production line, with the width of the rolling length increased from 30km to 60kmm, set a total length of 70 kilometers from the number of rolling up to 100 kilometers, the realization of complex, difficult to rolled products under the condition of mass production of free rolling.

【学位授予单位】：东北大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TG335

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