薄带钢拉矫机浪形矫平过程机理建模及有限元验证

采用弹塑性力学分析方法,针对拉伸弯曲矫直机用于对具有初始位移缺陷(瓢曲浪形)薄带钢的浪形矫平过程进行机理建模,推导建立以带钢规格材质及初始浪形参数、拉矫工艺参数和拉矫机相关设备参数为自变量的拉矫变形过程浪形矫平功效的解析预测模型。通过定义拉矫过程中带钢宽向进入塑性变形的屈服区域边界位置作为中间变量,以及依次分别建立各项输入条件与屈服位置的关系、屈服位置与工艺条件的关系,建立浪形矫平预测模型的多变量微分方程组。为了验证该机理模型的正确性,分析初始浪形、材料强度、带钢尺寸等初始条件以及弯曲辊半径、拉矫张力等工艺条件对拉矫机对于带钢浪形的矫平改善能力的影响,并应用ABAQUS软件另行建立同样条件下薄带钢拉弯矫直过程的有限元模型,经计算并对比计算结果,两种方法的结果吻合良好。     

弯曲卸载效应与冷轧带钢拉弯矫直延伸率关系研究

根据冷轧带钢拉伸弯曲矫直的基本假设,应用弹塑性理论,以经典的D、E型应力状态的带钢为例,分析并推导了带钢在弯曲弹复过程中应力应变的分布变化,提出了金属材料的弯曲卸载效应会增大带材中性层延伸率的观点,因此,在计算带材延伸率时弯曲卸载效应不可忽略。继而,建立了冷轧带钢拉矫过程有限元仿真分析模型,通过模型工况设置和结果数据分析,验证了冷轧带钢在不同张力与弯曲程度下,弯曲卸载效应对冷轧带钢中间层的延伸率产生影响,并就这种影响进行了定性描述。     

拉伸弯曲矫直机在铝带精整中的应用研究

论述了拉伸弯曲矫直机在铝带精整中的作用,参数对矫直效果的影响。拉伸弯曲矫直机属于高端有色金属精整加工设备,通过对带材的拉伸弯曲作用,能够有效地消除薄带波浪和翘曲等板形缺陷。在实际生产过程中,由于来料板型的不规则性,需要根据实际情况来调整机组参数。深入分析带材拉矫过程中拉力、矫直切入量、带材延伸率等关键技术参数对矫直效果的影响,以及各个参数的设定原则。带材的来料质量决定了延伸率的设定,在拉力达到最大的情况下,可通过调整切入量使拉矫效果达到最优。     

冷轧带钢拉矫工艺仿真参数修正方法的研究

带钢浪形导致带钢沿宽度方向上张力分布不均,在无浪处大于平均张应力,浪形越大,无浪处的张应力也越大。这一现象使得在有限元模型中计算出结果与实际结果差距较大。考虑到浪形对拉矫过程的影响,提出了冷轧带钢拉矫工艺仿真参数修正方法—板宽缩减比例系数K,并给出具体算法。通过两个现场案例与仿真结果的比较,验证了板宽缩减比例系数在研究拉矫工艺仿真应用上的有效性。不仅可以通过板宽缩减系数修正有限元模型中带钢施加的张应力,提高仿真结果的准确性;也为优化现场工艺参数提供了计算依据。     

拉弯矫直机破鳞机理的研究

拉弯矫直机工艺参数是影响矫直和破鳞效果的重要因素。通过研究拉弯矫直机的张力辊和弯曲辊的破鳞机理,结合拉伸、弯曲氧化铁皮剥落试验,发现弯曲作用比拉伸作用破鳞效果更好,且减小弯曲辊直径更能够显著提高拉弯矫直机除鳞效果。通过研究可对有效破鳞提供依据,对拉弯矫直机的结构设计和工艺参数的设定提供参考。     

铝型材多点三维拉压复合弯曲成形工艺

轻量化薄壁型材三维弯曲结构件是高端装备制造业中一种难成形加工的关键零部件。针对此类制件的高精度、低成本的成形需求,提出一种拉弯-压弯相结合的铝合金型材三维弯曲成形工艺,设计多点联动的拉压复合成形单元体结构,通过水平方向由夹钳带动拉弯,垂直方向由各单元体上液压执行机构压弯,实现"W"形三维弯曲零件的成形,并研制成形装备样机。建立分析成形过程及回弹预测的数值仿真模型,通过试验对模型的有效性进行验证,仿真结果与试验结果回弹变形一致,回弹预测最大误差小于15%。此外,研究拉力对矩形截面型材拉压复合成形件回弹变形的影响规律,预拉伸力较补拉伸力对成形件的回弹减小趋势更为明显,当预拉伸力从零达到临界塑性应力Aσ_s时,总回弹减少了26.81%,为保证成形件不发生截面畸变和破裂等成形缺陷,确定了预拉伸力为Aσ_s、补拉伸力为0.3Aσ_s的最优工艺参数。所提出的多点三维拉压复合弯曲成形工艺解决了W形一类型材传统三维拉弯无法实现的多向曲率半径复杂弯曲成形的技术难题,为实现镜面对称结构件的成对一次成形提供了一种新方法。     

拉伸弯曲矫直机张力与弯曲的配置关系研究

拉伸弯曲矫直机主要依靠现场经验进行张力与弯曲配置。为实现张力与弯曲作用在拉矫时的合理配置,在分析带材极限弯曲曲率计算方法的基础上,引入极限弯曲曲率修正系数,探讨其取值规律,并将极限弯曲曲率修正值作为拉矫时的最大曲率,得出拉矫时最大弯曲曲率和最小张力的确定方法,在满足平直度要求情况下,求得较优的拉矫工艺参数。通过实际验算,所得结论是合理可行的。     

Φ159高速托辊冲压轴承座工艺制造

在拉伸过程中，毛坯各部分的受力情况与变形情况都不同的，而且随着拉伸过程的进展也在变化。其中拉伸毛坯在凹模与凸模角区的变形，也影响拉伸过程的进行及拉伸件质量。当拉地变形程序过大时，拉伸筒件侧臂内作用的拉应力也大，会使凸模圆周角区附近的毛坯在拉应弯曲变形引起的应力共同作用下，产生过大的变形与厚度变，并且成为危险断面，因此研究保证筒形件工的拉伸工艺是十分重要的。     

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。     

管材无芯弯曲的最小相对弯曲半径

为了系统研究管材弯曲的变形实质,进行大量管材无芯弯曲试验.结合管材弯曲成形中外侧管壁材料切向受拉的变形现象,分别对可能发生的集中性拉伸失稳和分散性拉伸失稳变形进行分析.给出与管材力学性能相关,且受拉伸失稳约束的最小相对弯曲半径的计算公式,可用于工艺计算,并对管材弯曲成形设计和工艺分析具有一定的参考价值.通过相应的试验分析指出,由于管材制造所形成的残余应变使得材料在管型状态下所表现的力学性能有一定变化,因此管材弯曲作为二次塑性变形,其真实硬化模数及力学性能参数对弯曲过程中材料的失稳变形和最小相对弯曲半径的计算具有重要影响.     

Real-time tension control in a multi-stand rolling system

The problem of real-time tension control in a metal-strip processing line is addressed. The tension in a metal strip changes due to not only the speed difference but also thickness changes at the ends of a span. The mathematical dynamic model which describes relationship between the tension change and the roll-speed change is improved to include the effect of the strip thickness change on tension variation. Through the computer simulation of this model. the parameter sensitivity analysis and the static and dynamic characteristic study are carried out. The tension variation in a metal strip turned out to be very sensitive to the thickness variation as well as to the speed difference at the ends of the metal strip. In the rolling process, the master speed drive is usually located at the last stand. The speeds of rollers in upstream stands are adjusted with respect to the speed of the last stand to compensate the speed change for the tension regulation. A new tension control strategy in a multi-stand rolling process is suggested. The tension transfer phenomena is used in the design of the suggested controller. The developed mathematical model is used to design a controller for the real-time control system. A set of requirements for the real-time tension control is suggested. Based on the requirements, a real-time software for the tension control in a multi-stand system is designed and real-time simulation was carried out by using the Vx Works real-time scheduler and the Force Target board. The cancellation mechanism of the roll gap control due to the tension interaction is clearly defined by using the mathematical model derived in this study. It is confirmed that the suggested control strategy needs less control efforts and shows better performance than those of the existing control method in a rolling process.     

模拟板带轧制三维变形的流面条元法

提出模拟板带轧制过程三维变形的一种新的数值方法——流面条元法。沿着金属的流动轨迹,将变形区划分为若干流面(曲面)条元,为方便分析和计算,又将其映射为平面条元。横向位移和高向位移的纵向分布被分别构造为四次曲线和二次曲线,其横向分布均用三次样条插值函数表示,高向分布均用二次曲线拟合。根据塑性力学流动理论,分析推导了变形区三维变形和应力的数学模型。与曾经提出的流线条元法相比,考虑了应力与变形沿高向的不均匀分布,实现了精确的三维分析和计算。仿真实例表明,该方法和模型符合实际,为板带轧制过程的三维力学仿真提供了一个新的实用工程数值方法。     

Strip tension control considering the temperature change in Multi-Span systems

The mathematical model for tension behaviors of a moving web by Shin (2000) is extended to the tension model considering the thermal strain due to temperature variation in furnace. The extended model includes the terms that take into account the effect of the change of the Young’s Modulus, the thermal coefficient, and the thermal strain on the variation of strip tension. Computer simulation study proved that the extended tension model could be used to analyze tension behaviors even when the strip goes through temperature variation. By using the extended tension model, a new tension control method is suggested in this paper. The key factors of suggested tension control method include that the thermal strain of strip could be compensated by using the velocity adjustment of the helper-rollers. The computer simulation was carried out to confirm the performance of the suggested tension control method. Simulation results show that the suggested tension control logic not only overcomes the problem of the traditional tension control logic, but also improves the performance of tension control in a furnace of the CAL (Continuous Annealing Line).     

模拟带材轧制过程的条元法

本文介绍了模拟带材轧制过程三维应力与变形的一个新的工程实用方法——条元法。本方法对于四辊轧机冷轧带材单位轧制压力、两向单位摩擦力在变形区内的分布以及前、后张力横向分布的计算结果与实验结果吻合较好,证明用本方法模拟带轧材轧制过程是可行的。与三维差分法、三维有限元法及三维边界元法相比,本方法具有计算简便、经济和实用的特点。     

Stream surface strip element method for simulation of the three-dimensional deformations of plate and strip rolling

A new method—the stream surface strip element method (SSSEM)—for simulating the three-dimensional deformations of plate and strip rolling process is proposed. The rolling deformation zone is divided into a number of stream surface (curved surface) strip elements along metal flow traces, and the stream surface strip elements are mapped into the corresponding plane strip elements for analysis and computation. The longitudinal distributions of the lateral displacement and the altitudinal displacement of metal are constructed respectively to be a quartic curve and a quadratic curve, the transverse distributions of them are expressed as the third-power spline function, and the altitudinal distributions of them are fitted to be a quadratic curve. Based on the flow theory of plastic mechanics, the three-dimensional deformations and stresses of the deformation zone are analyzed and formulated. Compared with the streamline strip element method, the SSSEM considers the uneven distributions of stresses and deformations along altitudinal direction, and realizes an accurate three-dimensional analysis and computation. The simulation examples indicate that the method and the model of this paper are in accord with facts, and provide a new reliable engineering-computation method for the three-dimensional mechanics simulation of plate and strip rolling process.     

基于角点匹配的密封条截面图像分块配准算法

分析了汽车密封条传统检测方法的不足,针对现有方法无法测量的分块整体形变密封条,提出了一种基于角点匹配的轮廓分块配准算法。配准算法首先利用支持邻域求取轮廓角点,再利用分块角点匹配求取每块的仿射变换初值,最后利用基于最小二乘的搜索策略获得最佳配准效果。本算法在密封条存在较大分块形变时可实现有效测量,具有省去夹具装夹、节约测量时间和成本的优点。通过大量的实验证明,该方法的快速有效。     

On the full stand modeling and tension control for the hot strip finishing mill with PID structure

We describe a looper controller design for a hot strip finishing mill in steel plants. The main function of the looper system is to balance the mass flow of the strip by accumulating material in the middle of the stands. Another function is to control the strip tension which influences the width of the strip. To ensure strip quality, it is very important to control the tension of the hot strip finishing mill. However, because there is a mutual interaction between the looper angle and the strip tension, it is difficult to control the looper system. Previous researches examined only the operation of a single stand. But it is not sufficient to examine the operation and effect of whole stands because the operation is wholly interdependent. In this paper, we present a full model of the hot strip finishing mill in order to more effectively control strip tension. We propose several control methods for the full-stand hot strip finishing mill, denoted as conventional PI, PI with cross gain, and coefficient diagram method (CDM) PID control. In the real plants, there are some problems by using higher order controllers such as LQ, LQG and H∞. By comparison, the PID controller is very simple and easy to apply to all real plants. To that end, we present our findings on PID controls and their potential use in the hot strip finishing mill.     

A study on the fault diagnosis of the 3-d roll shape in cold rolling

The metal processing system usually consists of various components such as motors, work rolls, backup rolls, idle rolls, sensors, etc. Even a simple fault in a single component in the system may cause a serious damage on the final product. It is, therefore, necessary to diagnose the faults of the components to detect and prevent a system failure. Especially, the defects in a work roll are critical to the quality of strip. In this study, a new 3-D diagnosis method was developed for roll shape defects in rolling processes. The new method was induced from analyzing the rolling mechanism by using a rolling force model, a tension model, the Hitchcock’ s equation, and measurement of the strip thickness, etc. Computer simulation shows that the proposed method is very useful in the diagnosis of the 3-D roll shape.     

辊式带钢夹紧装置力能参数及张力放大机理研究

结合板带材弹塑性弯曲理论和S辊增力机理研究,详细分析了辊式带钢增力机构的增力原理,推导了计算公式,给出了机构的力能参数确定方法及对应的增力范围.根据实例对纵向增力进行了验算.结论对多辊夹紧增力机构的设计有重要的指导意义.     

钢带缠绕预应力模具变张力模糊控制

针对钢带缠绕预应力模具缠绕工艺中变张力控制问题,分析了影响张力控制稳定性的主要原因,提出了参数自整定模糊PID控制方法,设计了模糊控制器.在Matlab/Simulink环境下,建立了钢带缠绕预应力模具缠绕控制系统仿真模型.在相同条件下,对比了采用参数固定的常规PID控制和采用参数自整定模糊PID控制的张力控制效果,验证了模糊PID控制在改善系统动态和稳态性能方面的优势.