R2级表面镀锡板平整过程轧辊粗糙度衰减控制技术研究

针对某钢铁公司连退双机架湿平整机组生产R2级表面镀锡板工作辊表面粗糙度衰减速度快、轧制公里数偏低的问题,充分考虑到连退双机架湿平整机组的设备与工艺特点,从轧制工艺、轧辊使用工艺两方面深入分析了问题产生的原因,通过优化1#及2#机架工作辊原始表面粗糙度及伸长率分配系数建立了一套工作辊表面粗糙度衰减控制模型,并将模型应用到生产实践,大大降低了工作辊表面粗糙度的衰减速度,提高了轧制公里数,为企业创造了较大的经济效益。     

CVD金刚石膜激光平整化效率和粗糙度

对化学气相沉积(CVD)多晶金刚石膜进行激光平整化的正交试验,使用场发射环境扫描电子显微镜(SEM)进行形貌分析,激光共聚焦扫描显微镜测量线粗糙度Ra、面粗糙度S_a和切缝锥度,分析激光参数对CVD膜平整化的影响。结果表明：影响切缝锥度的因素依次为脉冲宽度、脉冲频率、进给速度和激光电流,影响线粗糙度Ra的因素依次为进给速度、激光电流、脉冲频率、脉冲宽度。正交试验优化后,当激光电流为64 A、脉冲宽度为400μs、脉冲频率为275 Hz、进给速度为100 mm/min时,可获得最佳的切槽表面形貌。采用该优化参数进行面扫描,测得面粗糙度S_a为11.7μm;进一步增加入射角度至75°时,面粗糙度S_a降低至1.9μm,实际去除效率达到1.1 mm³/min。     

平整轧制过程工艺参数对带钢残余应力场的影响

应用非线性有限元软件ABAQUS对平整轧制过程进行二维建模仿真,计算并分析轧辊与带钢间接触摩擦润滑条件、前后张力、压下率、工作辊辊径等工艺参数对平整轧制后带钢厚度方向上纵向残余应力分布的影响。仿真结果表明,轧辊与带钢间接触摩擦润滑条件对带钢厚度方向上的纵向残余应力的分布形式与数值影响很大;压下率与工作辊辊径对带钢厚度方向上的纵向残余应力的数值有一定影响。在轧机前后张力相同时,张力值的大小对带钢厚度方向上的纵向残余应力的分布形式与数值影响很小,可以忽略不计;在轧机前后张力不同时,其差值对带钢厚度方向上的纵向残余应力的数值影响很大,不能忽略。     

平整生产线带钢挫伤缺陷的原因分析

分析了带钢平整时出现挫伤缺陷的形貌和分布规律及其原因,挫伤缺陷是由相互挤压的带钢的相对滑动导致局部金属产生剪切滑移而形成的,带卷板面的不平滑区域与相邻平滑区域存在明显的半径突变,滑动时在与相邻层的接触面区产生足够的压力,导致局部金属产生剪切滑移。避免挫伤缺陷的主要方法是抑制开卷时带卷的层间滑动。     

平整工艺对冷轧带钢表面性能的影响

平整是带钢生产过程中一道非常重要的工序,不同的平整工艺对带钢的性能影响重大。采用表面粗糙度仪、扫描电镜以及原子力显微镜对不同平整工艺的冷轧带钢的表面粗糙度和表面显微形貌进行分析,研究干、湿平整工艺下带钢表面粗糙度和表面形貌的差异,通过测量不同平整方式下冷轧带钢的极化曲线,比较干、湿平整后带钢的耐蚀性能。结果表明,湿平整降低了表面粗糙度复制率,带钢的表面质量和耐蚀性能较好。     

热轧带钢平整机组的技术改进

分析了热轧带钢平整机组的生产工艺和设备的特点,针对宝钢热轧精整分厂的二辊平整机组存在的不足之处,提出了改造方案:增加下表面检查平台、废板夹送辊、废板输送链、末板废板倾翻装置、废料导板,改造出口剪后导板台等。使机组成材率增加1.5%,生产能力提高4万t/年。并提出对平整机组技术改进时应注意的问题,为平整机组的设计与改造提供了参考依据。     

冷轧平整过程轧制压力分布非线性有限元研究

利用非线性弹塑性有限元法,建立了冷轧平整过程仿真模型。运用该模型对平整轧制多组工况进行模拟,得到了薄带平整时轧制压力分布规律,与经典板带轧制理论中轧制压力具有单一峰值-摩擦峰不同,随着延伸率的改变,轧制压力分布呈现单峰、双峰等多峰分布。分析了张力、摩擦系数的变化对轧制压力分布的影响,模拟结果与实验数据基本一致。基于MSC.Marc软件平台,利用VB6.0开发了平整轧制过程专用有限元仿真软件,实现了冷轧平整过程的快速建模和仿真,结果后处理。     

湿平整过程中平整液流量差异性优化设定技术

针对以往湿平整轧制过程中平整液流量采用上、下辊缝等流量的设定方法,不但造成带钢上下表面延伸、粗糙度、耐蚀性以及清洁度存在差异,而且上辊缝平整液流量存在浪费问题,充分考虑到湿平整轧制的设备与工艺特点,提出了一套适合于湿平整轧制过程的平整液流量差异性优化设定技术,通过对上、下辊缝的平整液采用差异化的流量设定,在保证带钢的整体延伸、粗糙度复印、耐蚀以及清洁度的前提下,优化上、下辊缝平整液的流量分配,降低带钢上、下表面延伸、粗糙度、耐蚀性以及清洁度的差异,减少上辊缝平整液的浪费,最大程度的降低平整液的总消耗以及废液处理成本,达到节能减排、经济环保的目的。相关技术被投入到现场应用后,效果良好,为机组创造了较大的经济效益。     

冷轧带钢平整吹扫系统的优化改进

针对山东钢铁莱芜分公司冷轧线平整后带钢表面残留平整液斑的问题,结合现场生产实际,从压缩空气的纯净度、空气压力过程波动、吹扫强度不足等方面入手,通过采取增设储气罐、优化设计吹扫管道、改进吹扫梁等措施,大幅降低了平整液斑缺陷,提升了带钢的表面质量,减少了头尾切除量,综合成材率提高了1.65%。     

热轧薄规格超高强钢带钢平整矫直过程板形控制

针对传统热轧平整+矫直工艺对薄规格超高强钢带钢板形缺陷消除能力有限的问题,提出了精整板形控制策略,即采用大压下平整+大张力矫直工艺。对大压下平整+大张力矫直板形控制机理进行了分析;通过建立平整+矫直联合仿真模型,对大压下平整+大张力矫直工艺对瓢曲和翘曲缺陷的影响规律进行了数值模拟分析。结果表明：大压下平整+大张力矫直工艺中,平整工艺对瓢曲缺陷的消除能力强于矫直工艺,同时发现随着矫直机弯曲辊插入量以及张力的增大,带钢伸长率增大,并且在不同弯曲辊插入量下,带钢伸长率随张力增大的幅度不同,弯曲辊插入量越大时,带钢伸长率随张力增大的程度越大,对瓢曲缺陷的改善能力越强。对于翘曲缺陷而言,随着张力的增大,带钢上翘趋势越明显;随着弯曲辊插入量的增大,张力对带钢上下表面延伸差的影响越大,对翘曲缺陷的改善能力越强。     

Influence of roll radius on roughness transfer in skin-pass rolling of steel strip

Skin-pass rolling (or temper rolling) is usually the final process in the production of cold-rolled steel sheets. One of the main objectives in skin-pass rolling is to obtain a certain surface roughness profile. Although a large roll radius compared to the contact length and the reduction in thickness is one of the characteristics of skin-pass rolling conditions, numerous studies have been conducted thus far using laboratory mills with small radius rolls. In this paper, the influence of roll radius on roughness transfer in skin-pass rolling is investigated by experimental rolling tests as well as numerical analysis by elastic–plastic FEM. A simple but useful method of estimating roughness transfer is suggested. It was found that some characteristics of skin-pass rolling related to roughened rolls are not properly simulated using small radius rolls.     

Fundamental study of surface densification of PM gears by rolling using FE analysis

The complex shape of gears is very attractive to the near-net-shape PM technology. The strength of conventional PM parts is reduced by the residual porosity due to the power law relationship between the density and the mechanical properties. The maximum stresses in gears are found in the tooth root and the flank near or directly at the surface, so that by a local densification of the near surface layer the maximum load carrying capacity of the complete gear can be increased. This surface densification can be achieved by a rolling process. Due to the own elastic-plastic behavior of PM materials and due to the continuous change of the contact conditions during rolling, the process is too complex to be described analytically. To gain a better understanding of the process, the numerical simulation is a capable method. In this paper an FEA model is prepared and verified based on an experimental investigation. Additionally, case studies were carried out in order to analyze the relationship between the process parameters and the densification result. The investigations described in this present paper were sponsored by the WZL Gear Research-Circle.     

Influence of tool roughness and lubrication on contact conditions in skin-pass rolling

The special contact conditions in skin-pass rolling of steel strip are examined by experimental as well as numerical analysis studying plane strain upsetting of thin sheet with low reduction applying long narrow tools with smooth and roughened surfaces under dry friction and lubricated conditions. The influence of friction on the extent of a central sticking region is determined by an elasto-plastic FEM analysis of the plane strain upsetting. The experimental results obtained by measuring the local surface extension using markers made by Micro Vickers indentation verify the FE analysis and show significant influence of tool roughness and lubrication on the contact conditions for varying pressure. The central sticking region was larger for larger friction or tool roughness. At increasing pressure a sudden change in deformation pattern appeared with drastic elongation and sliding in case of lubrication. This deformation pattern is also affected by the tool roughness.     

棒线材多道次轧制过程的静力隐式有限元模拟及模型优化

借助有限元分析软件MSC.Marc,采用三维热机耦合有限元模型和静力隐式算法,对多道次连轧稳态轧制过程进行模拟分析。模型中轧辊间距采用真实尺寸。基于静力隐式算法的特性,在优化模型中引入刚性推动体,实现模型的简化。比较优化前后两种有限元模型的模拟结果及参数,表明该文所建立的优化模型可以在保证较好的计算精度前提下,显著地提高运算效率。应用优化模型模拟粗轧六道次连轧过程,温度变化模拟结果与实际测量结果吻合较好。     

滚压有限元模型数值模拟

滚压数值模拟是制定滚压工艺、预测滚压后工件表面残余应力分布,以及判定工件疲劳性能的重要工具。目前的滚压数值模拟主要集中在对曲轴以及回转体的分析,少有的对平面滚压数值模拟中,大多数也只分析了单圈或不到一圈的滚压过程,而且与实际滚压工艺存在较大的区别。为弥补以上不足,该文采用有限元商业软件ABAQUS提供的Explicit模块,并结合python编程语言,开发了更接近于实际的滚压模拟过程;采用该模型研究了滚压力的大小、滚针直径、表面摩擦系数等对于残余应力分布规律的影响,并通过H13钢的滚压实验,对模型模拟结果进行了验证。     

Influence of roll radius on contact condition and material deformation in skin-pass rolling of steel strip

Skin-pass rolling (or temper rolling) is the final forming step in the production of cold rolled steel sheets. Although a large roll radius compared to the contact length is one of the characteristics of skin-pass rolling conditions, numerous studies have been conducted thus far using laboratory mills with small radius rolls. In this paper, the influence of roll radius on the contact condition and material deformation in skin-pass rolling is examined and clarified by numerical analysis by an elastic–plastic FEM analysis as well as experimental rolling tests, which were performed to verify the result of the analysis. Some characteristics of skin-pass rolling related to pressure distribution, contact condition and material deformation are not properly simulated using small radius rolls. Considering characteristic skin-pass rolling conditions, two cases using simplified models, i.e., vertical compression and rolling with a circular, rigid roll, were analyzed.     

用改进的有限元模型分析二辊斜轧穿孔过程

借助有限元软件MSC.SuperForm2005,建立了新型的2D模型.采用Oyane断裂准则对圆坯二辊斜轧时的内撕裂形成过程进行二维热-力耦合数值模拟.模型中不仅反映了轧辊送进角和轧辊入口锥角的影响,而且还考虑了辊径的影响.结合宝钢140 mm全浮芯棒连轧机组Diescher穿孔机的工具和变形参数,分析了管坯斜轧时的应力应变状态和韧性断裂的特征值的分布状况,得到了管坯临界压下率.数值模拟结果与实际吻合较好,从而对生产过程合理确定变形参数有指导意义.     

主应力法计算蛇形轧制的轧制力

使用主应力法建立蛇形轧制过程中轧制力与轧制力矩的解析预测模型。将解析模型的计算结果与实验结果进行比较,验证了解析模型的准确性。运用该模型对蛇形轧制过程中不同的异速比、轧辊偏移距离、压下量和摩擦系数对轧制力和轧制力矩的影响规律进行研究。同时研究"搓轧区"对轧制力和轧制力矩的影响。结果表明,异速比的增大将导致"搓轧区"的增大,从而使轧制力和上轧辊轧制力矩减小,下轧辊轧制力矩增加。当异速比增大到速度较大的轧辊带动速度较小的轧辊时,慢速轧辊的轧制力矩将变为负值。轧辊错位距离的增大导致"搓轧区"减小,从而导致轧制力增加,上、下轧辊轧制力矩减小。压下量的增加导致"搓轧区"的减小,从而导致轧制力和上、下轧辊轧制力矩的增加。轧辊与轧板之间摩擦系数的增加使"搓轧区"减小,同时导致轧制力和上、下轧辊轧制力矩同时减小。研究为蛇形轧制在超大厚度板材制造中的应用,提供了理论基础。     

A comparative study of slab deformation under heavy width reduction by sizing press and vertical rolling using FE analysis

A detailed comparison between the quality of slabs formed by sizing press and vertical rolling mill is presented. ABAQUS/explicit commercial finite element software with elasto-viscoplastic constitutive model for material is used to study the geometric characteristics and deformation pattern during width reduction in these processes. Finite element models developed for both sizing press and vertical rolling processes are validated by comparing their results with experimental data available in literature. Parametric studies are performed using validated finite element models for sizing press mill to determine the effect of input process parameters such as initial slab width and thickness, width reduction and transfer pitch on the process outputs such as dogbone formation, head and end fishtail profiles, width necking at the leading end of the slab and slab edge quality. Similarly, developed finite element models for vertical rolling are used to investigate the effects of different input parameters on the slab deformation after passing through a vertical rolling stand with the aim of comparing the two width reduction processes. According to the results, benefits and drawbacks of each width reduction method are discussed. The enhancing effect of subsequent horizontal rolling after sizing press and vertical rolling processes on the final slab thickness is also presented.     

Dynamic explicit FE modeling of hot ring rolling process

1Introduction Ring rolling is an advanced process typically used to manufacture parts with revolved geometries.It makes use of rotating rolls to press a ring continuously and locally,causing the wall thickness of the ring to reduce,the diameter to expand …