连退平整机组带钢过焊缝过程中板形控制技术研究

针对连退平整机组带钢过焊缝过程中板形波动的问题,充分考虑连退平整机组的设备与工艺特点,以中间辊弯辊力对轧制压力进行补偿,以工作辊弯辊力对前后张力进行补偿,建立了板形控制模型。通过理论模型与现场试验相配合,实现了中间辊弯辊力和工作辊弯辊力的动态补偿,最大程度地减少了板形的波动幅度。     

八辊轧机板形预报模型及应用

在分析八辊轧机结构特点的基础上,结合八辊轧机的设备与工艺特点,对金属塑性变形模型和辊系弹性变形模型两个模型进行耦合,开发了一套适合于八辊冷轧机组的板形预报模型,给出了相应的板形计算流程图,并将模型应用到某冷轧厂1450八辊冷轧机组的生产实践中,开发出了相应的板形预报软件。现场使用效果表明：预报软件预报效果良好,能够较大幅度地降低板形封闭率,给企业带来较大的经济效益。     

热镀锌连退过程带钢横向拉窄量控制技术的研究

在连退过程中带钢存在横向拉窄量较大或横向不均匀拉窄的问题,这会增加带钢板形缺陷的风险,同时带钢的尺寸精度不能有效保证。首先建立连退过程带钢横向拉窄量预报模型,并在此基础上分析得到影响带钢横向拉窄的可控因素有张力、温度以及工艺段内板形。为兼顾下个工艺段板形对拉窄量的影响,将本工艺段内板形加以控制,从而降低板形对下个工艺段的影响。由此以张力和温度为优化变量,建立以连退过程带钢横向拉窄量为目标函数的控制方法,综合优化本工艺段板形及横向拉窄量。最后,将本控制方法应用于某机组实际生产,取得良好效果。     

中厚板矫直机的压下规程对矫直精度的影响模拟分析

针对实践需求及存在问题,在大变形矫直原理的基础上,对某公司改进设计后的九辊中厚板辊式矫直机,建立了矫直辊压下量的数学模型。并采用LS-DYNA软件对40 mm厚度的Q345中厚板模拟矫直过程,通过分析矫后板材残余应力及板形平直度的变化情况,研究矫直辊的压下规程对中厚板矫直精度的影响。结果表明:矫后中厚板纵向上的残余应力最大、厚度方向上的残余应力最小;合理地矫直辊的压下规程,不仅可以使矫后板材的残余应力最小,还能明显地改善板材的平直度。     

四辊轧机非常态轧制时板形模型的研究

针对四辊轧机工作过程中可能出现的上下左右不对称问题,在大量的现场试验与理论研究的基础上,充分结合四辊轧机的设备与非常态轧制的工艺特点,从辊系弹性变形模型入手,充分考虑到四辊轧机非常态轧制过程中的上下与左右的不对称性,建立一套适合于四辊轧机非常态轧制时的板形模型,编制相应的板形分析与控制软件,利用该模型及软件不但可以定量预报出带材跑偏、不对称辊型、轧制中心线与轧辊中心线不重合、不对称弯辊、不对称窜辊等非常态因素单独或综合作用对轧机成品板形的影响,而且可以定量预报出对称弯辊、对称窜辊、倾辊等常态因素对成品板形的影响。该模型及软件已经被应用到梅钢1420双机架平整机组的板形分析与控制,有效地提高了机组的成品板形质量,板形封闭率从项目开展前的2.5%降低到目前的0.5%以内,给机组创造了较大的经济效益,具有进一步推广应用的价值。     

热带钢轧机线性变凸度工作辊的研制及应用

为改善轧机的板形调控性能,在分析连续变凸度(Continuously variable crown,CVC)辊形技术的板形控制特性的基础上,开发出用于热带钢轧机的线性变凸度(Linearly variable crown,LVC)工作辊辊形技术及其相应的板形控制模型。LVC技术的板形调节能力与窜辊量成线性关系,同时与带钢宽度成近似线性关系。在满足宽带钢板形控制要求的同时,提高轧机对窄带钢的板形控制能力,使轧制各种规格带钢时所需弯辊力处于合理的的幅值。在1 700 mm热带钢轧机上一年多的工业应用表明,采用LVC工作辊后,板形控制精度提高30%以上,尤其是轧制高强度钢种时,凸度下降显著,轧制公里数一般都大于55 km,磨损辊形和轧辊消耗与常规工作辊基本一致。     

热轧平整矫直机的设计和应用

热轧钢卷精整生产中,辊式矫直机布置于开卷机与平整机之间,是入口主要设备之一,全程对带钢进行矫直,用来消除带钢内部的残余应力,改善板形。文中依据弹塑性弯曲理论,结合热轧平整生产的工艺特点,分析了矫直机的辊数、辊径等重要结构参数的选择,并详细介绍了矫直机的结构形式、控制模式、运行精度。     

冷轧板形测量值计算模型的研究与应用

为了得到准确的板形测量值,通过分析板形辊的结构与板形测量原理,制定板形测量信号的标定及滤波处理方法。为了补偿带钢横向厚差对板形测量的影响,建立轧后带钢横向厚度分布模型,把各个测量段处的带钢厚度引入张应力分布计算模型中,提高了带钢张应力分布计算的精度。根据带钢与板形辊的接触状态设定带钢边部板形测量值的补偿计算模型,用于修正未被带钢边部全部覆盖的传感器所测径向力。针对轧制过程中板形辊上某些传感器会出现故障的情况,制定故障测量段的插值计算方法。给出由各测量段板形测量值向若干个特征点处板形值的转换模型,简化板形控制系统中的数据处理过程。板形测量值计算模型已用于1450冷连轧机的板形控制系统改造中,经现场应用表明,模型具有较高的精度,为冷轧板带生产实现精确的板形控制提供条件。     

热轧平整机组中六辊矫直机探讨

本文介绍了平整机组中一种六辊矫直机对热轧带钢的矫正,对矫直机的功能结构特点进行了描述,并对矫直力等参数进行了理论计算.     

小型专用拉弯矫直机的设计与工艺研究

镀锌薄钢带经常大量应用于冷弯型钢生产中,而在其生产过程中很容易出现板形缺陷。常见的辊式弯曲矫直设备通过单纯弯曲变形对钢带实施矫直,但无法胜任薄带复杂板形的矫正。拉伸弯曲矫直方法将拉伸和弯曲两种矫直工艺相结合,改变了钢带中性层的位置,经过多次拉直、弯曲能够实现钢带全截面延伸,能够同时实现钢带侧弯、波浪变形、坯料楔形等不良板形的矫直。为此我们开发了一种专门用于冷弯生产的小型拉弯矫直设备实现薄钢带的矫直功能。不但详述了设备机械、电气的研制与开发,而且采用有限元分析和现场试验相结合的方式,对特定产品的拉弯矫直工艺进行了研究。     

冷轧超高强钢平直度与断面形状前馈控制技术

针对六机架冷连轧机组超高强钢生产过程中因机架数多、控制工艺复杂、各机架控制能力得不到充分发挥而导致成品平直度与断面形状超差的问题,充分结合六机架冷连轧机组的设备与工艺特点,基于超高强钢冷轧过程平直度与断面形状预报模型,分析了超高强钢冷连轧过程平直度与断面形状前馈控制策略,提出了基于来料的各机架出口目标平直度曲线设定方法,开发了适合于六机架冷连轧机组的超高强钢平直度与断面形状前馈控制技术。将该技术应用到某钢厂六机架冷连轧机组,各机架控制能力得到了充分发挥,成品平直度比该技术应用前提高了12.5%,且断面形状分布更加均匀,具有进一步推广应用的价值。     

边浪带材拉伸弯曲矫直有限元模拟曲率分析

带材在轧制过程中由于延伸不均匀使内部产生残余应力,当应力值达到一定程度时就会造成板带的浪形等三维板形缺陷。采用有限元软件ANSYS／LS--DYNA分析研究金属带材边浪的生成及拉伸弯曲矫直过程。分析拉伸、压缩和拉弯3种情况下边浪带材的初始曲率发生的变化及矫直卸载后残余曲率分布状态,为生产现场选取较佳的矫直工艺参数提供帮助。     

连退机组焊接质量影响模型及其影响因素的研究

针对连退机组焊机焊接带钢过程中焊接参数无法完成优化配置、技术人员无法定量分析焊接质量的问题,考虑连退机组焊机的设备与工艺特点,在分析焊接质量综合影响模型的基础上,选择典型规格带钢,对碾压轮压力、焊机压力、焊接电流、搭接量、焊接速度等影响焊接质量的因素进行了定量分析。通过调整上述因素,使焊接质量综合目标函数值控制在一定范围内,进而获得焊接参数的浮动范围,并根据最优焊接工艺参数进行现场验证,满足了工厂带钢焊接质量需求。同时,将该连退机组焊接质量综合影响模型应用于国内某连退机组焊机实践生产,开发了相应软件,提高了机组的带钢生产效率与成品带钢的焊接质量预报精度。     

[制造与维修工艺]高速轨端部平直度控制方法的研究与运用

为解决钢轨端部平直度不达标的问题,分析了高速轨端部平直度不合格的原因,指出钢轨每道次进轧机时的冲击力和出钢时走势不正是导致端部原始曲率大小和方向各不相同,经矫直后造成端部平直度不稳定的原因。针对端部平直度不稳定的问题,采用大变形+小变形矫直方案,设计正交试验,得到最优矫直压力参数;分析矫前矫后平直度数据,得出矫前原始曲率控制范围。通过上述措施,优化矫直工艺后的钢轨端部平直度完全满足标准要求,并稳定控制在较窄的波动范围内。     

Research and application of non-symmetrical roll bending control of cold rolling mill

The existing research of the flatness control for strip cold rolling mainly focuses on the calculation of the optimum adjustment of individual flatness actuator in accordance with the flatness deviation,which can be used for general flatness control.However,it does not work for some special rolling processes,such as the elimination of ultra single side edge-waves and the prevention of strip break due to tilting roll control overshooting.For the purpose of solving these problems,the influences of non-symmetrical work roll bending and intermediate roll bending on flatness control were analyzed by studying efficiencies of them.Moreover,impacts of two kinds of non-symmetrical roll bending control on the pressure distribution between rolls were studied theoretically.A non-symmetrical work roll bending model was developed by theoretical analysis in accordance with practical conditions.The model was applied to the revamp of a 1250 6-H reversible universal crown mill (UCM) cold mill.Theoretical study and practical applications show that the coordination utilization of the non-symmetrical work roll bending control and tilting roll control was effective in flatness control when there appeared bad strip single side edge waves,especially when the incoming strip was with a wedge shape.In addition,the risk of strip break due to tilting control overshooting could be reduced.Furthermore,the non-symmetrical roll bending control can reduce the extent of uneven distribution of pressure between rolls caused by intermediate roll shifting in flatness control and slow down roll wear.The non-symmetrical roll bending control technology has important theoretical and practical significance to better flatness control.     

扭绞方钢调直机的设计

重点介绍一种新型钢筋调直切断机,对送料、调直、切断等相关环节对机器的设计理念进行分析,并通过对调直角度以及切断力的计算,得出了相关的技术参数,对扭绞方钢在生产中存在内应力过大以及表面划伤严重这两个问题进行分析并给出了解决措施。     

PROFILE AND FLATNESS CONTROL SYSTEM IN 1 700 mm HOT STRIP MILLS OF ANSTEEL

Varying contact-length backup roll and linearly variable crown work roll are provided for improving the mill performance of profile and flatness control. Integrated with theses technologies, relevant profile and flatness control models are developed for hot strip mills on the basis of large amount of finite element calculation. These models include shape setup control model in process control system, bending force feedforward control model, crown feedback control model and flatness feedback control model in basis automation system. Such a profile and flatness control system with full functions is applied in 1 700 mm industrial hot strip mills of Ansteel. Large amount of production data shows that the crown precision with the tolerance of±18 μm is over 90%, the strip percentage which the actual flatness is within ±25 I-unit surpasses 96%, and general roll consume is reduced by 28% by using the profile and fiatness control system. In addition, schedule-free rolling is realized.     

Flatness Control Based on Dynamic Effective Matrix for Cold Strip Mills

Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. FLatness control is the key and highly difficult technique of strip mills. The boule-neck restricting the improvement of flatness control techniques is that the research on flatness theories and control mathematic models is not in accordance with the requirement of technique developments. To build a simple, rapid and accurate explicit formulation control model has become an urgent need for the development of flatness control technique. This paper puts forward the conception of dynamic effective matrix based on the effective matrix method for flatness control proposed by the authors under the consideration of the influence of the change of parameters in rolling processes on the effective matrix, and the concept is validated by industrial productions. Three methods of the effective matrix generation are induced: the calculation method based on the flatness prediction model; the calcuLation method based on the data excavation in rolling processes and the direct calculation method based on the network model. A fuzzy neural network effective matrix model is built based on the clusters, and then the network structure is optimized and the high-speed-calculation problem of the dynamic effective matrix is solved. The flatness control scheme for cold strip mills is proposed based on the dynamic effective matrix. On stand 5 of the 1 220 mm five-stand 4-high cold strip tandem miU, the industrial experiment with the control methods of tilting roll and bending roll is done by the control scheme of the static effective matrix and the dynamic effective matrix, respectively. The experiment result proves that the control effect of the dynamic effective matrix is much better than that of the static effective matrix. This paper proposes a new idea and method for the dynamic flatness control in the rolling processes of cold snip mills and develops the theory and model of the flatness control effective matrix method.     

Cutting edge orthogonal contact-zone analysis using detailed tool shape representation

A new method for numerically controlled (NC)-simulation-based numerical analysis of the tool-workpiece contact area in cutting processes is presented. To gain enhanced knowledge about tool-workpiece interaction, determination of chip thickness, contact length, and resulting cross-section area of the undeformed chip is of major interest. Compared to common simulation approaches, where rotationally symmetrically constructed tool shape is used, the new method uses a detailed three-dimensional tool shape model for an extended and more accurate contact zone analysis. As a corresponding representation of the workpiece and its time-dependent change of shape, a multidexel model is used. To perform contact zone analysis, each cutting element and a multidexel model are intersected in discrete time steps corresponding to the tool rotation. Subsequently, the intersection point of each dexel is mapped on the local coordinate system of the cutting geometry. The parametric cutting geometry allows a direct computation of local cutting depth and contact length for each involved point. Based on the local values of contact length and cross section area of the undeformed chip, the characteristic values for the entire contact zone are calculated and used to predict mechanical loads caused by the cutting process. To demonstrate the application of the novel approach, a prediction of forces in slot milling and drilling of 1.1191 steel (C45EN) is presented.