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1、 燕 山 大 学本科毕业设计英文文献翻译冷轧薄带时，轧辊边缘接触对轧制参数的影响摘要在一些冷轧制造中,当轧制薄带的时候，工作辊边部接触而且使薄带变形的问题已经被发现。问题就出现在边缘上, 在这篇文章中，分析了轧制中薄带与工作辊接触产生的变形，作者把重心集中在研究轧制特定的力上，正如轧制力,中间的力, 边缘接触力和变形的效果。薄带在冷轧中，当工作辊边缘接触的时候。一种有效的方法产生了，就是模拟这个特别的轧制程序。基于数字的模拟, 轧制参数的效果，我们能获得轧制过程中变形的效果。数字的模拟测试已经查证这个发展了的方法的有效性。关键词:薄带轧制;边缘力；弯曲力；工作辊1. 介绍冷轧薄带被广泛的应用在
2、电子和仪器行业当中。随着科学和技术的迅速发展，薄带已经越来越广泛的应用在工业当中。大体上, 这种薄带被一个工作辊将铸坯轧制成索需要的形状。Sutcliffe等人为薄带的轧制研究了一种新的方法进行负载和轧制力的测量。在薄的薄带轧制中, 一个比较估计轧辊扭矩和一个被修正横向分布的方法也已经被研究出来。Jiang 等人计算薄带的柔性变形, 和在薄带的冷轧中的薄带的形、轮廓和平整度。轧辊的柔性变形导致轮廓、外形和平坦、平整度的问题。该如何改良它的外形和平整度，还有尺寸精度，一直是与钢铁的生产者相关的主要问题。研究员已经从新的制造工厂中发现对这些问题的解决办法,正如生产出轧辊连续变型(CVC)和轧辊交叉
3、(PC)的轧机。轧辊交叉和工作辊弯曲，有了这些轧制程序，能够使当相对厚的薄带被轧制的时候，工作辊彼此不接触。在一些冷轧过程中，例如当薄带被轧制的时候，工作辊的端部接触而且变形(见图1)。在冷轧薄带的分析中，工作辊端部接触的问题能够导致毁灭性的结构不能不考虑。在这情况, 模拟变形的模型的技巧不同于传统的薄带冷轧程序。不仅仅改变工作辊边缘接触时的压力分布，而且也是工作辊的损坏的模型。当工作辊接触超过轧件的边缘该如何决定旋转力、中间力, 边缘接触力时，轧辊会产生变形。通过轧件的描绘来改善它的质量这是研究的主要特征。作者这篇文章的重点在于冷轧过程中旋转参数对特定的力量和轧件的描绘效果的研究。 当轧件超
4、出轧辊接触边缘时，Edwards和Spooner根据一个分析方法也简短地描述了冷轧薄带毁坏兼容性关系。但是到目前为止详细的结果还没有被报告。基于数字的模拟,旋转参数和改变，冷轧过程中边缘的损坏的效果被演示出来。数字的模拟测试已近证明这样研究的可行性。2. 基本的方程式 变形轧辊在工作辊和支撑辊之间，工作辊和轧件之间，是以工作辊之间的换置兼容性关系为基础的。由于左边和右边的对称，那铸坯在轧辊的中心线快速前进,一半轧辊当做一个研究目的被分离出来,而且分开区域在图 2 被显示出来。工作辊和支撑辊之间的轧制力在该区域是统一的。轧辊和轧件的毁坏在图 2 被表示出来。在工作辊和支撑辊之间，由于弯曲,修剪,
5、浦松氏比, 弯曲片刻, 冲突，通过计算轧辊歪斜得到不成形的工作卷物描绘，以上内容在下列的段落中会详细介绍。2.1. 轧辊弯曲变形 给一个弯曲应力会导致轧辊倾斜。一个典型的轧辊歪斜模型如图3 所示。轧辊歪斜在弯曲力的效果之下在一个位置 x 能被描述为: E是弯曲模量，I是横截面积。2.2. 调整轧辊变形通过 Oconnor 和 Weinstein，轧辊变形可以调整为: A是横截面积，G是剪切模量。2.3. 由于弯曲轧辊变形如果有弯曲,中间的歪斜轴能在图 4 被显示出来而且表示成: M 弯曲力矩，R(x) 在 x 位置的轧辊的半径。2.4. 由于 浦松氏比的效果卷歪斜卷物中轴的歪斜由于在表面运动的
6、浦松氏比是 R 是工作辊半径。2.5. 工作辊和支撑辊之间的紧度基于假定长的接触的柔性气缸, 压力在适中的大小，-轧辊压力 q(x) 能通过下面的公式能够被表达出来。ywb(x) 是紧度在工作辊和支撑辊之间; 写在底下的数字 W 和 B 分别地提及工作辊和支撑辊 。 CW 和 CB 被下列的方程式决定: v 是浦松氏比。基于轧辊的等高线, 紧度在工作辊和支撑辊之间能被计算 ywb(o) 薄带中心是完全的轧辊紧度的地方,yb(x) 全体的支撑辊-桥的挠度、和 CB(x)完全的支撑辊隆起包括平面隆起, 热的隆起和轧辊磨耗。 yw(x) 全体工作辊-桥的挠度,而且 CW(x) 完全的工作辊隆起包括平
7、面加冠, 热的隆起和轧辊磨耗。2.6. 工作辊变平 工作轧辊在工作轧辊的接触面积变平和薄带能被描述为 B 是薄带宽度, 而且 yH(x) 由 : p(x) 是旋转的压力, 而且 b 1 和 b 2 是被实验 16 决定的常数. 因为软钢(0.1-0.25% C), b 1 和 b 2 分别地被估计当做 32.92 和0.86 毫米 2/kN。当轧制洋铁的时候，薄带可能是非常薄的，而且工作轧辊的挠度能充份造成工作轧辊接触超过薄带的边缘。时下轧辊弯曲系统是应用分开工作轧辊从彼此超过薄带的边缘。 在工作轧辊之间的紧度,yww(x),然后能依下列各项被计算: L 是工作辊的宽度, h(o) 出口薄带在
8、薄带中心的厚度。 屈服图 5 、左边和右手边超过那被卷的薄带的边缘叫做轧辊边缘接触区域。 p(x)和 p分别是(x)连络压力在工作轧辊在左边和右手连络区域。3. 模拟 下面是被用在模拟冷轧方面的重要参数的价值: 工作辊的直径: 400 mm； 支撑辊的直径: 1200 mm； 工作辊的长度: 1600 mm； 支撑辊的长度: 1600 mm； 工作辊的初次隆起: 0.0 mm； 支撑辊的初次隆起: 0.0 mm； 中心距在螺旋之间: 2700 mm； 中心距在弯曲气缸之间: 2700 mm； 工作的杨氏模数卷: 220000 N/mm； 支撑辊的杨氏模数: 22000 N/mm； 工作辊的浦松
9、氏比: 0.3; 支撑辊的浦松氏比: 0.3; 板层厚度: 2.02 mm； 进入薄带的厚度: 0.45,0.40, 0.35 或 0.32 mm； 薄带的出口厚度: 0.3 mm； 薄带的宽度: 1000 mm； 特定的前面拉力: 165 N/mm； 特定的背部之里面拉力: 160 N/mm； 旋转的速度: 1000 m/min; 磨擦系数: 0.017; 在进入的薄带的初次隆起: 0.0 mm； 定义来自边缘的薄带隆起的点: 25 mm； 工作轧辊弯曲力: 0,50, 100 或 150 kN/chock.轧制力由福特-希尔公式计算B 是轧制前的薄带的宽度, 拉力因数, kp 被描述的变形
10、阻力，由下列方程得:是一个常数, 污染率, 写在底下的 s 指示静止的和ks 是静止的变形阻力,k0 一个常数,在这一 公式 k0=740MPa ， m 和 n 是常数,m=0.01 和 n=0.23, m 是平均的整体还原被描述为H1 是板层厚度是一个常数。 (0.75) 半径是一将工作辊的半径变平卷能被 Hitchcock 模型推论: b 是轧制、 H 薄带的宽度, h 薄带的出口厚度,操作轧辊半径, CH Hitchcock 系数 和 F 轧制力。 DP 能被描述为 磨擦系数。 工作辊和支撑辊的挠度使用简单梁理论计算弯曲和剪切。4. 结果基于影响力功能方法, 模拟程序表在个人计算机上发展
11、起来。 获得为不同的轧制薄带入口的厚度, 弯曲力和工作的状态或没有边缘接触力； 旋转的力、中间的力, 边缘接触力和薄带的轮廓。4.1.薄带对特性的进入厚度的效果板层厚度是 2.02 毫米, 薄带的出口厚度是0.30 毫米和弯曲力是零。 进入厚度的效果在特定的力上的薄带在图 6 被显示。 它能被见到，旋转的力增加当进入薄带的厚度增加。 因为还原增加当做薄带的进入厚度增加。 它也被见到那中间的力增加当进入厚度薄带增加, 而且它在边有一个逐渐增加的趋势由于边缘接触工作轧辊快速前进。 当进入厚度是 0.32 毫米，边缘接触力是零, 这方法没有边缘接触。边缘接触力用薄带 (还原) 的进入厚度的增大. 那
12、边缘工作轧辊的接触变得更重要当薄带增大的进入厚度, 有一重要的在中间的力方面的影响力。图 7 表演薄带的出口厚度的分布对于不同进入厚度的薄带。当进入厚度薄带增大它能被见到那出口薄带的隆起增加.(也见表 1) 因此, 即使工作轧辊连络超过薄带的边当弯曲力是零, 被卷的薄带的轮廓变成具有进入厚度的增加。4.2. 边缘接触对特定的效果板层厚度是 2.02 毫米, 进入厚度 0.40 毫米,出口厚度 0.30 毫米，弯曲力是零。 特定的力作用下的效果边缘接触如图 8所示 。 它能反应当边缘接触的时候，在薄带的边附近的旋转的力减少。 因为边缘接触工作轧辊，边缘接触力增大和那中间的力超过薄带的边也增加。因
13、此，旋转的力减少。 边缘接触的效果在薄带的轮廓上在图 9 显示出来。 很轻易能发现那出口薄带的隆起的减少。工作轧辊接触彼此的边缘.(见表 2) 因此工作轧辊的边缘接触能改良轮廓。如果没有在薄带中被应用的卷板机系统。4.3. 弯曲在特性方面的力的效果板层厚度是 2.02 毫米, 进入厚度 0.40 毫米,出口厚度 0.30 毫米。 弯曲特性方面的力的效果力在如图10 所示。 它能反应当弯曲力增大的时候在轧辊边缘的力的减小。 然而, 当宽度里面的中间的力使薄带减少，然后在边缘附近增的力和那当弯曲应力增加的时候，就能操作轧辊。 因为边缘接触的效果, 接近的中间力工作的边缘卷桶稍微增加。 当弯曲力增加
14、, 中间增大力时，使工作的边缘卷桶变得更重要。 我们能看到边缘接触力减少，弯曲力增加的时候，表示那边缘接触力可能是可以忽略的。这时弯曲应力150kN/chock。 当弯曲力增大时，薄带的轮廓变成比较的弯曲。(见到图 11) 因此,减少边缘接触力而有效的改良边缘变形的方法就是增大弯曲应力。5. 结论这是一个研究轧辊在轧制过程中通过模拟边缘力和弯曲应力而改善轧辊作用下薄带边缘变形的模型。 结果表示那些特定的力，像是旋转的力,中间的力而且对于薄带轧制这种特殊的生产过程所造成的特别的影响。 当薄带的厚度增加的时候, 那边缘接触力增大, 工作的边缘接触轧辊变得非常重要, 在中间施加作用力所产生的中还要得
15、效果就是使,出口薄带的形变成很小的。 如果没有弯曲应力的作用，薄带在出口处的隆起将会减小，工作辊边缘的变形也随之减小。 因为边缘接触能改良薄带的轮廓，因此各个生产厂家已经引入了边缘检出应力分析的装置来提升薄带生产的产品质量。在这些装置的作用下，薄带的变形变的微乎其微。 因此, 增加弯曲和应力能够在成产过程中很大程度上减小薄带边缘在工作辊作用下的变形。 这项研究是澳大利亚的一个研究所投资进行研究的。Effect of rolling parameters on cold rolling of thin stripduring work roll edge contactAbstractIn so
16、me cold rolling mills, a problem has been found that the sides of work rolls touch and deform when thin strip is rolled. The problem of work roll contact at the edges, which forms a new deformation feature in rolling, is analysed. In this paper, the authors focus on the research of the effects of ro
17、lling parameters on specific force such as rolling force, intermediate force, edge contact force and the profile of thin strip in cold rolling when the work roll edges contact. An influence function method is developed to simulate this special rolling process. Based on numerical simulation, the effe
18、cts of the rolling parameters on the mechanics and deformation of the cold rolled thin strip are obtained. Numerical simulation tests have verified the validity of this developed method.1. IntroductionA cold rolled thin strip is widely used in the electronic and instrument industries. With the rapid
19、 development of science and technology, thin strip has been finding more and more applications in industry. In general, this kind of strip is produced by a tandem cold rolling mill where the work rolls are flattened to a non-circular deformed shape . Sutcliffe et al. developed a robust model for rol
20、ling of thin strip and foil and carried out the experimental measurements of load and strip profile during thin strip rolling. In thin strip rolling, a comparison of methods to estimate the roll torque and a modified method for lateral spread has also been conducted . Jiang et al. calculated the ela
21、stic deformation of strip, and the shape, profile and flatness of strip in cold rolling of thin strip. Elastic deformation of the rolls brings about problems of profile, shape and flatness . The problem on how to improve its shape and flatness, and the dimensional accuracy has always been of major i
22、nterest to the steel manufacturers. Researchers have found solutions to these problems by introducing new types of mills, such as continuous variable crown (CVC) and pair cross (PC) mills equipped with roll shifting, roll crossing and work roll bending . These are rolling processes where the work ro
23、lls do not contact each other when relatively thick strip is rolled.In some cold rolling mills, for example, it has often been found that the edges of work rolls touch and deform (see Fig. 1) when the thin strip is rolled. The problem of work roll contact at the edges should be considered in an anal
24、ysis of the cold rolling of thin strip, which forms a new deformation feature. In this case, the models of deformation and mechanics are different from the traditional cold rolling processes of strip. Not only the distribution of the roll pressure will change when the work rolls contact beyond the e
25、dges of the strip, but also the deformation model of work rolls, friction at the interface of the rolls and the strip and work roll wear. How to determine the rolling force, intermediate force, edge contact force and profile of the strip, to improve its quality when the work rolls contact beyond the
26、 edges of the strip is the main feature of this study. The authors focus on the research of the effect of rolling parameters on specific force and profile of thin strip in cold rolling, which is a highlight of this paper.Edwards and Spooner also described briefly deformation compatibility relationsh
27、ip for the cold rolling of the thin strip when the work rolls contact beyond the edges of strip by an analysis method. But up to now detailed results have not been reported. In this study, an influence function method has been developed to simulate this special rolling process. Based on the numerica
28、l simulation, the effect of the rolling parameters on the mechanics and deformation of the cold rolling of thin strip are obtained. Numerical simulation tests have verified the validity of this developed method.2. Basic equationsThe calculation of the deformed rolls is based on the displacement comp
29、atibility relationships between the work roll and backup roll, work roll and thin strip, and the work rolls. Due to symmetry of the left and right sides of the rolls at the central line of the roll barrels, one-half of the roll barrels is selected as a research objective, and the equal divided zone
30、is shown in Fig. 2. The rolling pressure and the pressure between the work roll and backup roll are uniform in zone. The deformations of the rolls and the strip are described in Fig. 2. The deformed work roll profile is obtained by calculating the roll deflections due to bending, shear, effect of Po
31、issons ratio, bending moment, interference between the work roll and the backup roll, and work roll flattening, which are described in the following paragraphs.2.1. Roll deflection due to bendingBeam theory for the bending and shear components has been widely employed to calculate the roll deflectio
32、ns . A typical roll deflection model under the effect of point load is shown in Fig. 3.The roll deflection of the beam under the effect of bending at a position x can be described as follows:where E is the Youngs modulus, I the second moment of area, p(z) and q(z) the point loads2.2. Roll deflection
33、 due to shearAccording to Oconnor and Weinstein , the deflection of the neutral axis for short stubby beams due to shear is given bywhere A is the cross-sectional area and G the shear modulus of the beam.2.3. Roll deflection due to a bending momentIf there is a bending moment, the deflection of the
34、neutral axis can be illustrated in Fig. 4 and expressed as follows:Where v is the Poissons ratio, M the bending moment, and R(x) the radius of the roll at x position.2.4. Roll deflection due to the effect of Poissons ratioThe deflection of the roll neutral axis due to the effect of Poissons ratio on
35、 the movement of the surfaces isgiven bywhere R is the work roll radius.2.5. Interference between work roll and backup rollBased on the assumption of two infinitely long elastic cylinders in contact, the interference under inter-roll pressure can be described as followswhere is the interference betw
36、een the work roll and backup roll; subscripts W and B refer to the work roll and backup roll, respectively. and are determined by the following equation:where v is the Poissons ratio. Based on the contours of the rolls, the interference between the work roll and backup roll can be calculated as foll
37、owswhere ywb(o) is the total roll interference at the strip centre, yb(x) the total backup roll-axis deflection, and CB(x) the total backup roll crown including ground crown, thermal crown and roll wear. yw(x) the total work roll-axis deflection, and CW(x) the total work roll crown including ground
38、crown, thermal crown and roll wear.2.6. Work roll flatteningWork roll flattening at the contact area of work roll and strip can be described as followswhere B is the strip width, and yH(x) is given bywhere p(x) is the rolling pressure, and b1 and b2 are constants determined by experiments . For mild
39、 steel (0.10.25% C), b1 and b2 are estimated as 32.92 and 0.86mm2/kN, respectively. When rolling tinplate, the strip can be very thin and the deflection of work rolls can be sufficient to result in work roll contact beyond the edges of the strip. Nowadays the roll bending systems are employed to sep
40、arate work rolls from touching each other beyond the edges of the strip. The interference between work rolls, yww(x), can then be calculated as follows:where L is the width of work roll barrel, h(o) the exit strip thickness at the strip centre.Given in Fig. 5, the left and right hand sides beyond th
41、e edges of the strip being rolled are named roll edge contact region. p_(x) and p_(x) are contact pressures between the work rolls at the left and right hand contact regions, respectively.3. Simulation conditionsGiven below are values of the important parameters used in the simulation for cold rolli
42、ng: Diameter of the work roll: 400 mm; Diameter of the backup roll: 1200 mm; Length of the work roll barrel: 1600 mm; Length of the backup roll barrel: 1600 mm; Initial crown of the work roll: 0.0 mm; Initial crown of the backup roll: 0.0 mm; Center distance between housing screw: 2700 mm; Center di
43、stance between bending cylinder: 2700 mm; Youngs modulus of the work roll: 220 000 N/mm2; Youngs modulus of the backup roll: 22 000 N/mm2; Poissons ratio of the work roll: 0.3; Poissons ratio of the backup roll: 0.3; Slab thickness: 2.02 mm; Entry thickness of strip: 0.45, 0.40, 0.35 or 0.32 mm; Exi
44、t thickness of strip: 0.3 mm; Width of strip: 1000 mm; Specific front tension: 165 N/mm2; Specific back tension: 160 N/mm2; Rolling speed: 1000 m/min; Friction coefficient: 0.017; Initial crown of strip at entry: 0.0 mm; Defining point of strip crown from edge: 25 mm; Work roll bending force: 0, 50,
45、 100 or 150 kN/chock.Rolling force is calculated by using BlandFordHill modelwhere B is the width of strip before rolling, the tension factor, kp the deformation resistance which can be described by the following equation:where is a constant, the stain rate, subscript s indicates static andwhere ks
46、is the static deformation resistance, which is determined under a constant stain rate 103 s1, k0 a constant, in this simulation k0 = 740MPa, m and n are constants, m = 0.01 and n = 0.23, m is average integral reduction which can be described aswhere H1 is slab thickness andwhere is a constant (0.75)
47、. R_ is a flatten radius of work roll which can be deduced by Hitchcock model:where b is the width of strip after rolling, H, h the entry and exit thickness of strip, respectively, R the radius of the work roll, CH the Hitchcock coefficient 9, and F the rolling force. DP can be described aswhere is the reduction and the friction coefficient.Deflections of the work roll and backup roll are calculated by using simple beam theory for bending and shear.4. ResultsBased on the influence function method, a simulation program was developed and performed on a PC. For different