2250mm热连轧机带钢板廓控制研究

发布时间：2018-03-19 21:09

本文选题：热连轧机　切入点：宽带钢　出处：《北京科技大学》2015年博士论文　论文类型：学位论文

【摘要】：2250mm热连轧机是目前国内宽度最大的“超宽”热轧中薄板生产线,与1450mm、1700mm等宽带钢轧机相比,该轧机的显著特征是辊径基本不变,但辊身长度增加了30%-50%,导致辊系横向刚度明显下降,轧机力学行为更加复杂,并且该轧机的产品规格也比一般的宽带钢轧机复杂。因此,该轧机在与板形有关的轧机刚度、辊系受力变形、轧辊磨损和热胀等方面的非对称性和局部性特点更加突出。由此而导致实际生产中,带钢经常出现板廓非对称、局部高点等缺陷,严重影响了产品板形质量。本文以某2250mm热连轧机为研究对象,将理论分析和数值计算、实验研究相结合,针对超宽带钢板廓形状非对称和局部高点缺陷的形成和遗传规律等进行了深入研究,结合该热连轧机生产线的自身特点及板形控制手段对板廓缺陷控制进行了探讨和应用研究。本文的主要工作和成果如下： (1)根据大量带钢板廓测量分析发现,超宽轧机带钢板廓非对称和局部高点等缺陷的存在,传统凸度和楔形指标无法准确描述带钢板廓形状,从而导致板形质量控制和评价的精度降低。因此,通过研究超宽轧机带钢板廓的缺陷特征及其对板形控制的影响,针对性地提出了局部高点参数识别方法、板廓不对称度的非对称指标以及基于局部板廓权重的带钢板廓估计方法,为带钢板廓的描述和控制提供了新的思路。 (2)测量并分析了2250mm热连轧机的轧机和轧件所处的非对称状态,并利用非对称辊系变形模型和遗传效应方法,研究了超宽带钢板廓非对称的形成过程,明确了多种非对称因素对板廓的影响作用及其在连轧过程中的遗传规律。 (3)针对由于超宽热连轧机轧制计划复杂多样、CVC窜辊特点和带钢表面横向温度分布特点等引起的工作辊严重不均匀磨损,及其对板廓形状的遗传特性,提出并实现了基于带钢板廓形状的工作辊不均匀磨损计算模型,为轧辊磨损的在线计算提供了新方法。 (4)利用局部的轧件变形模型,研究了局部高点的形成和演变过程,发现各机架工作辊局部磨损是造成带钢出现局部高点的主要原因,且下游机架工作辊磨损是决定性因素。为改善带钢板廓质量,进行了高速钢轧辊在热连轧机组下游机架的使用研究,结果表明高速钢轧辊的使用有效改善了带钢板廓形状。 (5)根据理论和生产数据的分析结论,提出并实施了轧机刚度、轧件跑偏、轧件横向温度分布的调控标准、高速钢轧辊的使用规范以及轧制计划的调整等方案,使2250mm热连轧机板廓缺陷基本得到控制,由板廓缺陷引起的板形质量缺陷改判率从2012年的1.2%下降到2014年的0.02%。
[Abstract]:2250mm Hot Strip Mill is currently the largest domestic sheet width "wide" hot rolling production line, and 1450mm, compared to 1700mm wide strip mill, rolling mill is a salient feature of the roll diameter is almost the same, but the length of the roll roll system leads to increased 30%-50%, lateral stiffness decreased, the mechanical behavior of rolling mill is more complicated and the product specifications of the mill than wide strip mill general complex. Therefore, the mill in the flatness and the rigidity of mill, roll system deformation, roll wear and thermal aspects of non symmetry and local characteristics more prominent. Caused by the actual production, often appear in the strip asymmetric profile, local high point defects, seriously affect the product quality of flatness.
This paper takes a 2250mm Hot Rolling Mill as the research object, theoretical analysis and numerical calculation, experimental research combined with ultra wideband plate profile of asymmetric and local high point defect formation and genetic regularity is studied, combined with the hot rolling production line of its own characteristics and shape control methods of plate profile the defect control and its application are discussed in this paper. The main work and achievements are as follows:
(1) according to a large number of strip profile measurement and analysis found that the ultra wide rolling mill asymmetric and local high point defects such as strip profile, traditional convexity and wedge index cannot accurately describe the strip profile, thereby lowering the plate shape quality control and evaluation of accuracy. Therefore, through the influence of ultra wide defect characteristics strip profile and shape control of plate mill, puts forward the local point method of parameter identification of asymmetric index profile asymmetry and method of plate strip profile estimation based on weighted local plate profile, provides a new way to describe and control the strip profile.
(2) measurement and analysis of the non symmetric state of rolling mill and rolling mill at 2250mm Hot rolling, and the use of non symmetric roll deformation model and genetic effect method, studies the ultra wideband non symmetrical profile plate forming process, clear the influence of various factors on the asymmetric plate profile as well as genetic law in in the rolling process.
(3) due to the ultra wide hot strip mill rolling plan is complicated, and CVC work roll shifting characteristics and strip surface transverse temperature distribution characteristics caused by uneven wear, and genetic characteristics of plate profile, proposed and implemented work roll strip profile uneven wear calculation model based on the a new method is provided for the calculation of on-line roll wear.
(4) using local deformation model, the formation and evolution of the local point is studied, found that the frame of work roll wear is mainly caused by the local strip local high point, and the downstream frame work roll wear is the decisive factor to improve the quality of strip profile., made of high speed steel rolls in hot rolling of the results show that the downstream unit frame, the use of high speed steel roll can effectively improve the strip profile.
(5) according to the conclusions of the analysis theory and production data, proposed and implemented the rigidity of rolling mill, rolling deviation, control rolling transverse temperature distribution, adjustment scheme to regulate the use of high speed steel roll and rolling plan, make the 2250mm Hot Strip Mill profile defects of basic to control plate shape quality defects caused by commuted the plate profile defect rate decreased from 1.2% in 2012 to 0.02%. in 2014

【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG334.9

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