热镀锌光整机辊型曲线设计

板形和表面质量是光整热镀锌板的重要质量指标.针对光整热镀锌板的生产工艺特点,以带材前张应力横向分布均匀作为目标函数,建立了一套针对热镀锌光整机的辊型曲线设计数学模型,并将其应用于攀钢热镀锌光整机的辊型设计.工业应用表明:新的辊型曲线提高了工作辊弯辊的控制效果,改善了轧制压力横向分布均匀性,提高了热镀锌板的光整质量.     

光亮表面镀锡板及DI材的表面粗糙度试验研究

镀锡板表面粗糙度试验研究结果表明,生产光亮表面镀锡板时,提高平整辊粗糙度,可延长平整辊的使用寿命和提高原板的粗度,显著降低镀 锡板木纹、锡结晶、锡层及原反擦划伤等表面缺陷,并提高了镀锡板的使用性能,通过优化DI材平整辊配置,使DI材粗糙度得到稳定控制并养活了平整辊种类,提高了其利用率。     

Optimum Temper Rolling Degree: Pre‐Set and Influencing Effects of Bending Deformations

The present article describes a research project concerning the influence of bending deformations on strip mechanical properties imparted by temper rolling and a strategy for mill pre‐set to achieve the selected temper rolling degree in as short a time as possible. Research results show that, during strip temper rolling, rolls involved in the process, for example deflector rolls and anti‐sticking rolls, introduce plastic bending deformations into the strip which can amount to more than 30% of the temper rolling reduction, depending on the effective bending radii. Bending tests involving strips made of low‐carbon steel in a tension roller system with an integrated bending unit demonstrate that bending deformations influence the mechanical properties of the strip in a manner similar to the temper rolling process itself. It appears necessary to take account of the bending effects when selecting the optimum temper rolling degree. The most accurate roll force pre‐calculation possible and its application at the mill stand are of major importance for pre‐setting the required temper rolling degree. Existing analytical methods have been unable to yield the necessary calculation accuracy. Combination of an optimised analytical approach with a data‐based model to create a hybrid model has led to significant improvements. The accuracy achieved in the pre‐calculation of the required roll force has helped to improve mill pre‐set of the investigated temper mill and to reduce strip head‐end scrap on average by around 6 m per strip. Based on the annual outputs stated by the plant operator, this makes it possible to achieve a cost saving of more than 200,000 € per year.     

冷轧平整机板形问题的特点及对策

对某冷轧厂1700mm单机架平整机的板形问题进行了综合研究，发现该轧机在辊形加工、轧辊磨损及弯辊使用等方面存在的问题，并通过有限元模型研究了辊形对板形的作用，分析了平整上弯辊对板厚的影响，指出平整机板形问题的特殊性。针对平整板形的设备工艺特点，提出了新的辊形配置方案并正式投入生产。结果表明，改进后的辊形配置对降低弯辊调整量、改善板形、提高生产过程稳定性效果显著。     

四辊平整机组快速自由变规格轧制技术的开发

针对湿平整过程中在进行窄料变宽料生产时支撑辊换辊时间太长的问题,通过在轧制规格从窄到宽的切换过程中有意识地优化工作辊的换辊周期,安排部分工作辊采用小轧制周期轧制,利用新工作辊 “磨平”支撑辊辊面在从窄到宽轧制过程沿着辊身方向的不均匀磨损程度,在不更换支撑辊的前提下完成由窄变宽的规格切换,明显节省了变规格时的换辊时间,同时保证了产品质量和避免色差缺陷。该技术已被推广应用到梅钢1420连退机组四辊湿平整机组,使用效果良好,给企业创造了较大经济效益。     

热轧薄规格带钢平整过程板形控制技术

为了提高热轧薄规格带钢平整的板形质量,在平整机上采用了新的辊形配置。在支撑辊上采用变接触式 支撑辊辊形,在工作辊上采用六次方多项式正凸度辊形。变接触支撑辊辊形可以降低轧辊挠曲变形和边部应力的 集中,增大弯辊力的调控功效。采用正凸度工作辊辊形,可以弥补平整机的磨损辊形,延长平整轧制计划单位的长 度。此辊形配置在首钢迁钢热轧平整机上应用,保证了平整改善薄规格带钢板形质量,延长了平整轧制计划的长度。     

Development and application of roll contour configuration in temper rolling mill for hot rolled thin gauge steel strip

Abstract

In order to improve the flatness of hot rolled thin gauge steel strip, a new type of roll contour configuration was developed for a four-high temper rolling mill based on the finite element method analysis. The roll contour configuration consists of a variable contact back-up roll contour and a positive crown work roll contour. Both can be described as sixth order polynomial functions. The variable contact back-up roll not only reduces the roll stack deflection and contact stress concentration between work and back-up rolls, but also increases the control capability of the bending force of the work roll. Positive crown work roll contour is utilised to compensate roll wear and in turn the length of temper rolling schedule can be prolonged. After this roll contour configuration was applied on the temper rolling mill of Qiangang Company of Shougang Group, the flatness of hot rolled thin gauge strip was improved by 10% and the working efficiency was also increased as the length of temper rolling schedule was increased.     

冷轧平整机板形控制特性研究

针对某1500mm四辊冷轧平整机在轧制过程中产生的板形缺陷等问题,通过建立平整机辊系弹性变形有限元模型,对其板形调控特性进行了仿真分析,分析主要包括辊形、带钢宽度、轧制力、弯辊力的变化对辊系变形及辊间接触压力的影响,由仿真结果揭示出了平整机产生板形问题的机理,对指导实际生产具有重要意义。     

带钢表面振动纹的产生及其抑制

从振动纹的物理特征分析入手,阐述了振动纹与轧机振动之间的关系,通过对轧辊与磨床的振动测试和模态分析研究了轧辊辊系、工作辊轴承、主传动接轴和轧辊磨床对振动纹的影响.结果表明,振动纹是由板面振波由于对光的不同反射角度而引起的一种视觉现象;带钢振纹的产生有2种途径,一是轧机(平整机)发生了一定频率的振动,另一个是轧辊表面本身已有了振纹;可通过轧辊直径匹配法、定期监测滚动轴承倍频峰值、对磨床加装阻尼减振器、改变轧制速度和磨削速度、加强设备日常维护等措施对振动纹进行抑制.     

Setting method of rolling schedule for reversible four- high mill of narrow strip

The small four- high rolling mill of narrow strip has such structural features of small absolute value of working roll diameter, which causes problems like non- negligible horizontal displacement of the work rolls, larger thermal crown of the work roll, and more complicated shape control of the plate. The shape was more dependent on rolling schedule. The equipment and process characteristics of reversible four- high mill of narrow strip were fully considered. The influence model of rolling schedule of small four- high rolling mill on shape was established. The influence of specific path rolling schedule parameter on the shape was quantitatively analyzed. The targets were that the rolling pass was minimum and the relative load was the most uniform. Meanwhile, the influences of such factors as shape control, rolling stability and prevention of surface defects were also considered. A set of comprehensive optimization method for rolling schedule was put forward, which was suitable for small four high mill and taking account of shape control. Relevant technology was applied to the production practice of 450 small four high rolling mill in a company. Good results were achieved after the application in the field. The shape closure rate of the unit decreases by 45. 5%.     

冷轧高端电镀铬基板表面粗糙度控制研究

根据高端电镀铬基板后步工序的要求,结合鞍钢冷轧现有设备,研究了轧机轧辊粗糙度配置、轧辊磨削、干平整等工艺对于钢板表面粗糙度的影响,使得平整后表面粗糙度达到了0.1μm以下,表面光泽度达到了400,表面反射亮点满足要求,成功开发出具有鞍钢特色的高端电镀铬冷轧基板。     

冷轧带钢平整机支撑辊辊型优化技术的研究

 为提高板形控制效果,以板形最优为目标,建立了一套冷轧带钢平整机支撑辊辊型优化模型。为提高寻优速度,将目标函数进行转化,避免了金属模型与辊系模型的迭代计算,有效降低了计算时间,增加了算法的强壮性。将优化结果应用于凌钢900 mm平整机,生产实践表明,优化辊型可明显增强轧机的板形控制能力,降低弯辊负担,改善板形控制效果。     

热轧薄带平整机支撑辊辊型优化的研究与应用

某热轧薄带平整机轧辊长度为1 800 mm,带钢宽度为1 320 mm,两者相差太大,造成工作辊与支撑辊间有害接触区长度过大,在轧辊自身挠度作用下,辊间应力峰值集中于带钢边部位置.随轧制公里数延长,工作辊边部磨损加剧,不利于后期板形控制,同时会缩短轧辊使用寿命.针对热轧薄带平整机工作辊磨损不均匀问题,设计优化支撑辊辊型...     

FEM Analysis of Rolling Pressure Along Strip Width in Cold Rolling Process

 Using 3 D elastic plastic FEM, the cold strip rolling process in a 4 high mill was simulated. The elastic deformation of rolls, the plastic deformation of the strip, and the pressure between the work roll and the backup roll were taken into account. The distribution of rolling pressure along the strip width was obtained. Based on the simulation results, the peak value of rolling pressure and the location of the peak were analyzed under different rolling conditions. The effects of the roll bending force and the strip width on the distribution of rolling pressure along the width direction were determined.     

1800mmCVC热轧机辊缝凸度影响特性研究

采用有限元方法建立了某CVC热连轧轧机辊系变形模型,对影响辊缝凸度的各个影响因素如板宽,轧制力,弯辊力,工作辊直径,CVC工作辊窜辊,支持辊直径等进行了仿真研究,针对该轧机的凸度调控特性,得出了一些重要结果。     

Analysis of rolling load generated by pair crossed rolling mill

Abstract

Although a pair crossed rolling mill has a very high control capability of strip crown, a frictional force always occurs in the strip width direction between the strip and the work rolls. An analysis of rolling load was carried out, considering the shear deformation of strip cross-section caused by the frictional force. From the examination of the calculated results for a large-scale mill for production, the following conclusions were obtained: (a) the cross angle hardly influences the rolling force and torque, (b) the thrust force on the roll induced by the frictional force decreases as a result of shear deformation, (c) the thrust factor, i.e. the thrust force divided by the rolling force, is little influenced by the strip deformation resistance and the friction coefficient between the work rolls and the strip during hot rolling, (d) the thrust force applied to the rolls during hot rolling is 3–6% of the rolling force for the cross angle of 1° and this is not an obstacle related to the design of rolling mills.     

Design criteria for rolling contact fatigue resistance in back-up rolls

Abstract

This research centres on surface initiated damage on back-up rolls whereby rolling contact fatigue cracks can propagate into the rolls potentially reaching the internal stress fields and leading to catastrophic failure and has sought to establish design criteria for avoiding such failures. The project objectives have been achieved by examining field evidence, determining the loading and tribological conditions at the work roll/back-up roll interface and investigating both theoretically and experimentally the mechanisms involved in rolling contact fatigue in this case. The presented rolling contact, fatigue and fracture mechanics model includes criteria for crack branching either upwards (i.e.relative safety) or downwards (i.e.potentially catastrophic) and the link between these two cases is related, quantitatively, to the properties of the roll material. After linking mechanics to microstructure, the influence of work roll test disc surface roughness on both the surface wear of and the interaction between wear and rolling contact fatigue at the surface of back-up roll test discs has been quantified using the results obtained from experimental simulations carried out on a rolling–sliding testing machine. Finally practical quantitative recommendations are made for the mechanical and microstructural design of bainitic back-up roll materials, back-up roll redressing procedures and the surface roughness of both work rolls and back-up rolls presented to the mill.     

单辊驱动冷轧平整机振纹实测及振动机理分析

对某单辊驱动四辊冷轧平整机振动测试结果及其工作辊接触界面的摩擦学、阻尼特性,工作辊的稳定性,自激和受迫振动机理进行了分析。通过对振动信号的分析与比较,得到了平整机的振动特征以及振动与振纹之间的相互影响关系。在支撑辊使用初期,平整机振动的主要成分是自激振动,且自激振动的根源在于工作辊接触界面的负阻尼特性,而负阻尼产生源于轧制界面异步轧制搓轧区改变了摩擦力方向及辊间接触界面打滑现象的存在。在支撑辊使用中后期,由振纹引起的强迫振动加速了振纹的形成,系统的振动为强迫振动和自激振动共存。研究结果为解决实际生产中平整机振动带来的冷轧带钢质量问题提供了理论依据。     

冷轧极薄规格带钢羽痕缺陷生成机理与控制

针对双机架平整机生产极薄规格带钢时表面出现的羽痕缺陷生成机理进行了分析。通过研究发现,羽痕生成是由于极薄规格带钢在宽度方向上由轧制力和张力共同作用下出现不均匀变形,该变形产生的分界线在平整过程中出现了不均匀延伸;而在平整过程中由于弯辊和窜辊的预设定参数不合理、单位张力设定偏低、平整过程中弯辊力与轧制力不匹配等因素导致带钢局部延伸偏大,形成了明显的浪形,此浪形若经过平整机辊缝碾压则生成羽痕缺陷。通过将平整机设定张力提高30%、调整板形曲线为1~8 IU的大边浪、依照带钢厚度调整平整机板形预设定参数以及开发轧制力弯辊力跟随控制模型等措施,极薄规格带钢羽痕缺陷带出品由 206降至51 t/月,基板表面质量满足了国内外多家高端用户的要求。     

Directional Properties of Cold Rolled Non-oriented Electrical Steel Sheets

Applications of cold rolled non-oriented (CRNO) electrical steels demand uniform magnetic property in all directions. The objective of the present study was to investigate the magnetic properties of CRNO steel in different directions. Four different sets of samples were made from CRNO steel sheets—(1) samples along the rolling direction, (2) samples at 30° to the rolling direction, (3) samples at 60° to the rolling direction and (4) samples at 90° to the rolling direction. The textural and magnetic properties were investigated using standard techniques. X-ray diffraction and electron backscattered diffraction were used for bulk- and micro-texture measurements respectively. Single sheet tester was used for core loss and magnetic permeability measurements. The results showed different textural and magnetic properties in all the CRNO samples. However, the properties were always better in rolling direction where the texture was more.