六辊轧机辊系弹性变形研究

在板带轧制中,轧机辊系弹性变形是影响板形质量的重要因素.以弹性基础梁理论为基础,将辊间接触及工作辊与轧件间的接触采用弹簧模拟其力学模型,从而获得六辊冷轧机辊系弹性变形的解析数学模型;提出了一种将轧件断面形状分布与轧制压力分布耦合的迭代计算轧机辊系弹性变形和轧件最终断面形状的方法,利用MSC. MENTAT/MARC软件建立了六辊轧机辊系弹性变形的非线性接触有限元模型.计算结果表明:采用解析法、有限元法计算出的轧件断面形状与现场实测出的轧件断面形状及板带凸度数值相近,这说明研究方法和模型的有效性.     

六辊CVC轧机轧辊弯曲和压扁变形的有限元分析

采用非线性弹塑性有限元法,利用大型非线性有限元软件MSC.Marc建立了六辊CVC轧机轧制过程三维有限元仿真模型。模型将辊系弹性变形与轧件弹塑性变形耦合在一起,进行统一建模与分析。运用该模型分别改变工作辊弯辊力、中间辊弯辊力、中间辊横移量进行有限元模拟,得到了工作辊弯辊、中间辊弯辊、中间辊横移对六辊CVC轧机轧辊弯曲和压扁变形的影响规律。所建模型与分析结果可为六辊CVC轧机的板形控制研究提供理论数据与参考依据。     

弯辊和串辊对带钢板形影响

基于有限元软件ANSYS建立了冷轧六辊轧机的三维弹塑性有限元参数化模型。将轧机实体模型转换成有限元模型,根据轧机的工作方式提炼出边界条件和载荷条件,施加在有限元模型上。参数化模型采用ANSYS参数化设计语言APDL编写。通过修改程序中的参数,计算分析了弯辊力、中间辊的串辊量以及带钢宽度等参数对带钢形状和辊缝的影响。计算结果表明:当带钢宽度小于1 300 mm时,调整弯辊力对带钢板形的改变较为明显;当带钢宽度大于1 700 mm时,调整弯辊力对改变带钢板形的作用变得非常小,此时通过连续可变凸度轧辊（CVC）的串辊来调节板形更有效。该结论与冷轧厂实践结论一致。     

PC轧机辊系的三维建模与有限元分析

采用三维有限元法(ANSYS)建立PC轧机辊系的模型,并分析了PC轧机在不同工况下辊系弹性变形与工作辊/支撑辊的接触压力.计算结果表明,影响PC轧机轧件截面形状的主要因素是对辊交叉所产生的等效辊凸度.文中采用的建模与分析方法与其它方法相比,计算结果更为精确、可靠.     

连退炉导向辊热凸度对辊形及带钢应力分布的影响

为了更有效地控制连退炉内导向辊热凸度和改善带钢的跑偏及瓢曲变形,以单锥度辊为研究对象,运用MARC有限元软件,定量计算了在加热段和快冷段不同导向辊温差时的导向辊热凸度及其对导向辊辊形和带钢应力分布的影响.研究发现：导向辊热凸度随导向辊温差增大呈直线上升的趋势.在加热段,随着导向辊温差的增大,导向辊产生热凸度后的形状分别为双锥度辊、单锥度辊和“M”型辊,带钢张应力和带钢最大应力分布随着导向辊温差的增大而改变;在快冷段,导向辊产生热凸度后变为双锥度辊,导向辊热凸度会影响带钢张应力值和最大应力值,但不影响其分布.     

锥端支承辊对带材截面形状的影响

对四辊轧机锥端支承辊的使用特性进行了分析,结果表明与一般带凸度的支承辊相比,带钢截面形状更为平直从而改善了产品质量。本文采用特殊的求解接触问题的有限单元法对辊系的变形进行了计算,结果与实测值吻合。     

UC轧机中间辊非对称弯辊改善辊间压力分布

为了改善UC轧机辊间压力不均匀分布问题,采用中间辊非对称弯辊系统替代原有对称弯辊系统.应用影响函数法计算辊系变形,同时考虑辊缝中金属横向流动对带钢出口张力横向分布的影响,通过迭代方法计算出中间辊两端施加不同弯辊力后的辊间压力分布、出口厚度横向分布与出口张力横向分布.理论分析和实际应用结果表明,中间辊非对称弯辊可以改善辊间压力分布不均,降低轧辊磨损和减少轧辊辊面剥落,且不会影响成品带钢的厚度和板形.     

VC辊平整机板形调控性能的研究

以某厂连续退火平整机为研究对象,利用ANSYS有限元软件建立VC辊系静力学仿真模型,并研究了弯辊力、VC辊油压、轧辊辊径和辊套厚度对连续退火平整机板形控制能力的影响。结果表明,无论内、外弯辊如何配合,都不能达到只改变四次凸度的目的,不可能只通过内、外弯辊的配合来消除高次浪形;外弯辊的调控功效比内弯辊增大42%;VC辊油压的调控效果主要体现在二次凸度的改变上,改变油压后对四次凸度的影响不大;当VC辊承载时,油压不能始终保持辊套向外涨,承载时辊套可能发生反弯,向芯辊内凹陷;与大辊径相比,小辊径弯辊和油压的调控效果会增加,但辊缝横向刚度会降低;辊套壁厚的减小会使VC辊油压的调控能力有所提高。     

高速瓦楞辊机构凸度参数综合的有限元法

通过模拟瓦楞辊机构的全工作状态、附加力的约束、几何约束、温度场的约束等建立有限元模型进行分析,从而获得了垂直于轴线任一截面上的位移 本文将这些位移与瓦楞辊端截面位移之差定义为各截面的凸度,各截面凸度连线便是凸度曲线     

辊凸度连续可调（CVC）轧机的轧辊辊面曲线

讨论了辊凸度连续可调（Ｃｏｎｔｉｎｕｏｕｓｌｙ Ｖａｒｉａｂｌｅ Ｃｒｏｗｎ）轧机轧辊面曲线的形式，推导了曲线议程，对比了辊缝轮廓，同时还讨论了抽辊量、辊径差、轧件宽和曲线极值点位置对当量辊凸度的影响。     

轧辊弹性与热变形的耦合对带钢出口断面的影响

用影响函数法分析了冷轧风的四辊轧机辊系的弹性变形，并用有限单元法对轧机工作辊的热特性进行了三维模拟，耦合计算结果表明，轧辊的热特性对带钢的出口断面有重要影响，利用影响函数法和有限单元法耦合分析轧辊的弹性变形和热变表可以比较准确地预报轧件的出口断面。     

Gauge-meter model building based on the effect of elastic deformation of rolls in a plate mill

The calculation error of the gauge-meter model will affect the gap setting precision and the self-learn precision of rolling force. The precision of the gauge-meter model is strongly influenced by plate width, working roll radius, backup roll radius, working roll crown, backup roll crown, and rolling force. The influence rules are hard to get by measuring. Taking a conventional 4-h plate mill as the research subject, these influences were transferred into the calculation of roll deflection and flattening deformation. To calculate these deformations, the theory of the influence function method was adopted. By modifying the traditional gauge-meter model, a novel model of the effect of roll elastic deformation on the gap setting was built by data fitting. By this model, it was convenient to analyze the variation caused by the rolling condition. Combining the elastic deformation model of rolls with the kiss-rolls method, a gauge-meter model was put forward for plate thickness prediction. The prediction precision of thickness was greatly improved by the new gauge-meter model.     

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 a 1700 mm single-stand temper mill. Some critical problems such as the deviation of work roll contour caused by grinding and wear, the effectiveness of work roll bending were discussed. Using a finite element 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 some special features of flatness control in the temper mill: during temper rolling, roll deformation is slight due to small rolling load, and the loaded roll gap profile mainly depends on work roll contour, while the backup roll has a little effect on gap crown; the effect of bending force on gauge can not be ignored due to the coupling between flatness control and gauge control. A new roll contour 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 work roll bender, higher rolling stability, better strip profile and flatness quality.     

Preset model of bending force for 6-high reversing cold rolling mill based on genetic algorithm

The hydraulic roll-bending device was studied, which was widely used in modern cold rolling mills to regulate the strip flatness. The loaded roll gap crown mathematic model and the strip crown mathematic model of the reversing cold rolling process were established, and the deformation model of roll stack system of the 6-high 1 250 mm high crown (HC) reversing cold rolling mill was built by slit beam method. The simulation results show that, the quadratic component of strip crown decreases nearly linearly with the increase of the work roll bending force, when the shifting value of intermediate roll is determined by the rolling process. From the first pass to the fifth pass of reversing rolling process, the crown controllability of bending force is gradually weakened. Base on analyzing the relationship among the main factors associated with roll-bending force in reversing multi-pass rolling, such as strip width and rolling force, a preset mathematic model of bending force is developed by genetic algorithm. The simulation data demonstrate that the relative deviation of flatness criterions in each rolling pass is improved significantly and the mean relative deviation of all five passes is decreased from 25.1% to 1.7%. The model can keep good shape in multi-pass reversing cold rolling process with the high prediction accuracy and can be used to guide the production process.     

Backup roll contour of a SmartCrown tandem cold rolling mill

SmartCrown was a new system developed by VAI for improving the strip profile and flatness control first applied in 1700mm tandem cold rolling mills at Wuhan Iron & Steel (Group) Corporation (WISCO). After tracing and testing, the application of the conventional crown backup roll matching the SmartCrown work roll of the production mill led to heavy and nonuniform wear, and the edge spalling of the backup roll often occurred. A 3-dimension finite element model of roll stacks was established, which was used to analyze the above-mentioned problems, and it was found that the main reason was the highly nonuniform contact pressure distribution between the work roll and the backup roll. A new FSR (flexible shape backup roll) was developed and applied in 1700mm tandem cold rolling mills. A lot of good actual effects of FSR, such as evident improvement in profile and flatness of strips,non-occurring edge spalling, wear uniform, and remarkable decrease in roll consumption were validated by long-term industrial applications.     

VCR and ASR technology for profile and flatness control in hot strip mills

The roll contour pattern and variety of work and backup rolls in service and its effect on profile and flatness control performance in 1 700 mm hot strip mill at Wuhan Iron and Steel （Group） Corporation were tested and analyzed by the developed finite element models of different typical roll contours configurations. A rather smooth local work roll contour near strip edges and an increase in rolled length can be obtained by application of long stroke work roll shifting system with conventional work roll contours that is incapable of the crown control. In comparison with the conventional backup and work roll contours configuration, the crown control range by the roll bending force enhances by 12.79% and the roll gap stiffness increases by 25.26% with the developed asymmetry self-compensating work rolls（ASR） and varying contact backup rolls（VCR）. A better strip profile and flatness quality, an increase in coil numbers within the rolling campaign and a significant alleviated effect of severe work roll wear contours on performance of edge drop control are achieved by the application of ASR with crown control and wear control ability in downstream stand F5 and VCR in all stands of 1 700 mm hot strip mill.     

Q450冷弯成型角钢有限元数值模拟

采用非线性有限元法对冷弯成型过程中角钢各部位的应力、应变分布情况进行分析,并揭示了角钢在成型过程中金属的变形规律。结果表明,有限元模拟得出的板材应力、应变分布规律与实际情况相符舍,冷弯回弹模拟结果与实测回弹值存在一定的误差,模拟结果中回弹角随着成型角增加时的变化规律与实测结果一致。采用非线性有限元法对冷弯成型过程进行数值模拟是可行的。     

小支柱簇双层瓦推力轴承热弹流润滑性能分析

对Alstom公司三峡小支柱簇双层瓦试验推力轴承进行了热弹性流体动力润滑性能有限元分析。采用推力轴承润滑计算的有限元程序，并借助结构有限元程序ADINAT、ADINA的热传导和热弹变形分析功能，形成了一套完整的推力轴承热弹流动力润滑性能分析软件。物理模型包括润滑油膜、推力轴承和镜板推力头。对三峡试验推力轴承性能的计算结果和测量结果进行了对比分析。分析结果表明，计算结果和实测的结果吻合，试验模型使用的小支柱簇双层瓦可有效地控制瓦的热弹变形，进一步优化小支柱的弹性，还可补偿镜板的大部分变形。     

BEM Simulation on Elastic Deformation of Oil Film Bearing in Low Speed and Heavy Load Rolling Mill

1 Introduction Oil-filmbearing of rolling mill belongs to thick fil mlubrication. The current regularity of partial load e-nough certificates that partial load behaviors is the major causes that result in short-life and abnormal failure .Therefore ,howto decrease and eli minate partial load behaviors has become ani mportant wayto prolong bearinglife ,the exact elastic deformation of low-speed and heavy-load bearing under partial load helps tofurther analyzeits lubrication mechanism.Thelubricat…