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。     

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.     

六辊冷连轧机电工钢矩形断面控制弯辊力模型

为满足新一代高技术冷连轧机宽幅电工钢薄板等高端板材“Dead flat”矩形断面超平材超高板形质量要求,采用显式动力学有限元法建立六辊冷连轧机一体化仿真模型,利用现场工业轧制试验数据验证有限元模型的准确性,定量分析电工钢完整轧制过程中不同轧制因素对有载辊缝凸度的影响规律;基于6辊UCM冷轧机板形控制机理和课题组自主设计的EDW-N(Edge Drop Control Work Rolls for Non-shifting of the Work Rolls)工作辊非窜辊辊形建立六辊冷连轧机电工钢矩形断面控制的弯辊力数学模型;由有限元仿真与现场工业轧制试验结果确定了六辊冷连轧机电工钢矩形断面控制弯辊力数学模型的参数,并验证了其准确性;某大型1 420 mm六辊冷连轧机生产应用现场连续检测反馈数据表明：取得电工钢高精度出口凸度均值C15≤7μm的比例从38.58%提高到67.74%的显著生产实绩,充分发挥了六辊冷连轧机的高精度板形控制能力,可在很大调节范围内对板形质量进行调控,为解决无工作窜辊的6辊UCM冷连轧机宽幅电工钢薄板矩形断面控制瓶颈难题提供了解决方案和实现路径。     

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.     

WRS轧机工作辊横移方案及辊系变形研究

WRS轧机是一种板形调控能力较强的新型轧机.分析计算了不同工况下工作辊的磨损曲线并确定了最佳横移方案,同时对给定工况下的辊系变形进行了仿真计算.     

板带轧制断面形状调节的影响规律研究

为了分析各种断面形状调节手段对各次断面形状的影响规律,以HC轧机为例,以倾辊、工作辊弯辊、工作辊非对称弯辊和中间辊横移作为断面形状调节手段,按照机理模型计算了各调节手段对1次、2次、3次和4次断面形状的影响系数,系统地揭示了各种调节手段对各次断面形状的影响规律,为断面形状在线控制模型的建立、实现提供了基础。     

14辊轧机辊系变形的有限元分析

针对现场应用的14辊轧机,利用三维有限元软件MSC.MARC建立三维辊系弹性变形有限元模型,求解三维辊系复杂变形,分析第一中间辊抽动和中间辊凸度对承载辊缝的影响。研究得出第一中间辊抽动量在0-50mm时,带材边部厚度的调节范围;中间辊凸度与轧后板凸度呈线性关系,即中间辊凸度越大,辊系的横向刚度也越大。     

邻角精确控制的异型管辊弯成形过程数值模拟

针对汽车立柱用P形异型管多道次辊弯成形存在相邻凹凸角度偏差大、难以满足角度高精度要求的问题,基于弹塑性大变形理论,应用辊弯成形专业设计软件COPRA建立了P形异型管15道次辊弯成形有限元模型。结合实际生产过程,开展了完整成形过程的有限元仿真,分析发现焊管周长来料不足及P形异型管角部在轧辊孔型内金属流动不均、成形不到位是导致相邻凹凸角角度偏差过大的主要原因。结合仿真结果和生产实际,提出了选择合适的压缩系数、分配恰当的截面变形量和修正轧辊辊形三者相结合的邻角精确控制方法。应用所提方法进行了P形异型管辊弯成形有限元仿真,结果表明：仿真最终产品截面与设计截面基本一致,凹凸角的角度分别为90.5°和89.9°,角度偏差均在±1°的误差范围内;异型管辊弯成形金属流动到位,使得角部金属充满轧辊孔型,可改善P形异型管相邻凹凸角的成形质量。利用所提方法通过辊弯成形工业应用,获得了符合要求的P形异型管,其相邻凹凸角度精度分别提高了33.84%和36.70%,有效改善了P形异型管成形质量,可为生产实践提供依据。     

轧机弯辊和窜辊对轧辊轴承偏载的分析

现代化轧机在工作过程中,为了板形控制需要和延长轧辊工作时间,一般都设置有工作辊:弯辊及窜辊。除力能参数外,工作辊弯辊窜辊装置的结构对轧辊轴承的受力及寿命也有很大影响。运用ABAQUS有限元分析软件,建立了有限元分析模型,分析了实际工作中的轴承套圈与辊子的接触状态。通过对两种主要的弯窜结构在不同窜辊量状态下的偏载受力情况的有限元分析,得到了偏载下辊子沿轴向方向的接触应力分布的偏载效应规律,为轧机轴承的设计、制造及使用提供了参考。     

方矩形管连续辊弯成型延伸规律

为了减小方矩形管辊弯成型时纵向延伸,结合某厂实际生产工艺,建立了方矩形管辊弯成型七机架的三维弹塑性非线性有限元模型。通过仿真分析得到了方矩形管辊弯成型时横向金属流动规律及纵向延伸率的分布规律,与现场测量结果一致。分析了轧辊转速、管坯壁厚、辊径位置等因素对延伸率的影响,在此基础上优化了辊弯轧制工艺参数。结果表明:优化后的辊弯轧制工艺提高了方矩形管的成型质量,为预测最终成型尺寸精度和辊弯成形工艺参数的制定提供了理论依据。     

基于弹塑性变形理论的船体面板滚弯成形作业时间估算方法

为了准确估算船体面板滚弯成形作业时间,通过分析在滚弯过程中船体面板的弹塑性变化和滚弯成形后的最终状态,建立了滚弯成形最终状态下船体面板滚弯成形作业时间估算模型.与实测数据对比分析结果表明,基于弹塑性变形理论的总进给距离与实测进给距离无显著性差异,通过作业时间估算模型得出的理论作业时间与实测作业时间也无显著性差异而且相对误差都在10%以内(平均相对误差为5%).因此,基于弹塑性变形理论的船体面板滚弯成形作业时间估算模型合理且符合作业实际状况.     

Analysis of CVC roll contour and determination of roll crown

Mathematical analysis of continuous variable crown (CVC) roll contour used in CSP production line was conducted and the roll contour function of CVC roll was obtained. The validation with actual CVC roll contour shows that the calculation values of the roll contour function and the actual roll contour parameters given by equipment provider are the same, which proves that the roll contour function of CVC rolls given in this article is correct. The nonlinear relationship between the roll crown of CVC rolls and roll shift amounts was deduced. The concept of crown extremum was given.     

CVC轧辊辊形参数的确定

对CVC轧辊的辊形曲线进行数学解析,研究轧辊的轴向移动量与轧辊有效凸度的关系,推导辊形参数的理论计算公式,得到从工艺角度出发计算辊形系数A1的公式,并对某CSP厂CVC轧辊技术参数进行计算,提出其辊形参数的修正建议。     

Improved model to solve influence coefficients of work roll deflection

According to the concept of virtual bending force, a rational explanation for SHOHET’s model was presented. Considering the deformation characters of the work rolls in four-high mill, the deformation model of the work roll was regarded as a cantilever beam and new influence coefficients were deduced. The effect of the bending force was taken into account independently. Therefore, the contribution to work roll deflection caused by rolling load, rolling pressure between rolls and bending force can be got from the new formulas. To validate the accuracy of the formulas, the results obtained from the new formulas were compared with those from SHOHET’s formulas. It is found that they highly coincide, which illustrates that the formulas are reliable.     

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.     

Research of Elastic and Elastic-Plastic Deformation on Bending Problems of Variable Stiffness Beams

关于抗弯刚度变化的弯曲梁弹塑性变形问题的研究

黄磊,侯增选,张迪婧,赵有航

（大连理工大学 机械工程学院,大连 116024）

摘要：

本文构建一种新的可变刚度悬臂梁力学模型,以用于深入分析任意变刚度梁的弹性塑性弯曲问题。首先设定所要分析的梁是一种理想的各项同性的弹塑性材料,并且梁的各项材料参数如弹性模量惯性矩等均沿梁的轴线方向不断变化,同时考虑剪切对梁弯曲变形的影响。当梁在受到垂直集中力作用于梁的自由端时,分别给出在弹性阶段、塑性阶段全梁的挠度、转角微分方程。对于刚度任意变化的塑性阶段的变形分析,本文采用一种优化的微分求积分进行数值求解。最后分别通过MATLAB数值计算、DQM计算和abaqus有限元仿真分别分析了弯曲刚度轴向变化对悬臂梁的弹塑性变形的影响。数值仿真结果验证了该力学模型的实用性,并通过将微分求积法DQM的计算结果与有限元法的计算结果进行精度和效率的比较,结果表明DQM法在变刚度梁的复杂弹塑性行为的分析中不失为一种十分有效的科学方法。

关键词：剪切变形;弯曲问题;可变刚度;横截面;DQM法;弹塑性变形

     

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.     

型材滚弯数值模拟及应力、应变分析

用通用显式动力分析软件ANSYS/LS-DYNA成功实现了对型材弯曲件滚弯及其回弹过程的数值模拟.模拟结果表明,型材滚弯成形过程中,型材腹板应力中性层和应变中性层内移,而且应力中性层内移量大于应变中性层内移量.回弹后,等效弹性应变和等效应力的峰值变小.分析了型材弹塑性弯曲卸载过程中腹板截面的切向应力变化,模拟结果与理论分析一致.