辊弯方矩形管工艺参数优化

对方矩形管辊弯成形过程中机架间距、摩擦系数和轧制速度三个工艺参数的不同水平值进行了正交试验设计,用Abaqus有限元软件的显式非线性动态分析对所设计试验过程进行了模拟分析,求出各个道次各个参数的信噪比,获得了边部纵向应变峰值最小时各个道次三个工艺参数的最优值。并用优化后的参数模拟和验证之后,结果是各道次边部纵向应变峰值比优化前各组试验都小。优化后第4到第10道次纵向应变峰值的方差最小,也就是产品边部拉伸最小,并且边部拉伸分布均匀。     

热连轧带钢立-平辊多道次轧制热力耦合三维有限元模拟

对热连轧Q345B窄带钢精轧立-平辊多道次轧制进行了三维热力耦合有限元模拟,分析了轧制过程中轧件温度场、等效应力-应变场及轧件表面特征点流动规律。结果表明,模拟计算的带钢断面中心点温度及平轧各道次稳态轧制压力与实测值吻合良好;宽度方向轧件边、角部与中心温差较大是导致边部金属应变不协调,上翻至带钢边部表面的主要原因;轧件角、边部由于冷缩效应存在一定拉应力,会影响轧件角部缺陷的愈合或扩展;采用立辊侧压调宽对轧件边部减薄和翻平宽展可能造成的边部缺陷有明显的改善作用。表面节点位置变化规律可为现场轧制生产中轧件边部缺陷的溯源分析提供便利。     

立辊润滑工艺对铁素体区轧制Ti-IF钢组织性能及边部质量的影响

针对某热轧厂铁素体区轧制Ti-IF钢带钢边裂缺陷的问题,提出了采用立辊润滑的方法予以改善。分析认为,采用立辊润滑轧制工艺可减小立辊减宽过程中的摩擦力,减少低温下带钢边部表面的剪切力;同时,有利于立辊表面质量的改善,从而改善带钢边部质量。为此,研究了立辊润滑工艺对铁素体区轧制Ti-IF钢带钢微观组织、力学性能、析出物以及边部质量的影响。结果表明,采用立辊润滑轧制工艺,Ti-IF钢带钢的组织和析出物没有明显差异,但塑性显著提高;带钢边部表面的最大裂纹深度由361 μm减小到128 μm,边部缺陷数量明显减少;带钢截面形貌较为光滑,没有发现明显裂纹,边部质量得到明显改善。     

下山法成形在辊弯成形中的应用

在辊弯成形过程中,板材纵向拉伸过大将引起许多缺陷,目前减少纵向应变的主要方法是增加成形道次。下山法成形是一种应用在管类产品成形中减小纵向拉伸的有效方法。以屋脊瓦为例,利用计算机辅助设计软件COPRA进行设计与仿真,将下山法应用在非管类产品的成形过程中。结果表明,与传统方法相比,运用下山法成形,材料在各道次间的纵向应变明显减小,能有效防止各类缺陷的产生。     

1420mm六辊UCM冷连轧机边部减薄特性仿真分析

以某1420 mm五机架冷连轧镀锡基板生产机组为研究对象,利用Marc大型有限元软件平台建立了六辊UCM轧机轧制过程三维非线性仿真模型。通过数值模拟,深入研究了带钢边部减薄的重要影响因素,并系统分析了工作辊弯辊、中间辊弯辊、中间辊横移等板形控制手段对带钢边部减薄的调控特性,从而为辊型优化设计和边部减薄控制提供了理论基础和参考依据。     

地铁用高强度不锈钢弧形板冷弯成形过程的模拟及实验

针对不锈钢弧形板尺寸精度要求高导致成形工艺难度大的问题,以符拉索夫开口薄壁梁理论为基础,推导出符合高强度不锈钢弧形板成形过程中横向变形、纵向变形的能量计算式及弯曲角度的表达式,并编制出成形工艺。以理论计算为基础建立数学模型,模拟弧形板成形过程,根据在成形过程中出现的褶皱、翻边等问题对模型进行修正,增加侧辊,最终获得理想的板形。以成形过程中的轧制力大小及不锈钢弧形板成形后的回弹量;判定理论道次变形量分配的合理性。对合作企业的冷弯成形机组进行改造,依据最优仿真结果进行实验,反复修正后的工艺模型能顺利辊弯出高强度不锈钢弧形板产品,而且机组的轧制力能稳定,成形后的回弹量较小,产品质量满足用户精度要求。该研究对形成最优成形工艺,提高辊弯质量和精度具有重要指导作用。     

成型参数对HFW焊管排辊成型质量的影响

HFW(high frequency welding)焊管的排辊成型过程主要受材料、成型设计、工艺设计方面因素的影响。实际生产中需要知道各影响因素对产品成型质量的影响,为生产工艺的制定提供理论上的参数定性、定量选择依据。基于508 mm直缝焊管的排辊成型过程,利用有限元分析软件ABAQUS仿真,将带钢的成型形状、边部纵向应变曲线、边部PEEQ(等效塑性应变)曲线作为评价指标,探讨了成型速度、摩擦状态对管坯成型效果的影响。结果表明,在正常取值下,速度和摩擦状态对成型形状无较大影响,速度对边部纵向应变以及边部PEEQ影响较大,摩擦因数对边部纵向应变影响较大,对边部PEEQ基本无影响。     

薄壁铝合金封头旋压成形工艺研究

应用ANSYS软件对薄壁铝合金封头冷旋压成形过程进行了弹塑性有限元数值模拟.通过对球冠部分和翻边部分第1道次各阶段的应力应变分析,揭示了其成形时的塑性变形流动规律,并分析了几种主要工艺参数对成形质量的影响规律及失效问题产生的原因.研究结果表明：薄壁铝合金封头冷旋压成形的主要失效形式是翻边部分的外缘起皱,控制皱纹产生的有效方法是采用弯边措施增加外缘法兰的刚度、选择合适的第1道次倾角和采用较小的进给比.     

QP980钢后纵梁冲压工艺优化

针对某车型QP980钢后纵梁零件翻边成形时存在的边部开裂问题,基于Auto Form软件对原工艺方案进行了全工序仿真,并分析开裂原因。提出了解决开裂问题的5项工艺优化方案,并利用Auto Form软件对优化方案进行仿真评估。此外,对增加切角模、改变毛刺朝向、缓解开裂的原理进行了分析。结果表明:零件因边部减薄严重而导致开裂,常规预成形方案对缓解超高强钢边部开裂问题效果有限。解决此类问题的有效方案包含2类:优化产品边界、减少边部区域材料减薄率;改变该区域应变状态,将边部应变状态改为面内应变状态,提高材料抗减薄能力。此外,改变毛刺朝向能在一定程度上缓解零件边部开裂问题。通过对该问题的研究,总结出影响该零件翻边成形时边部开裂问题的主要因素及解决方案,便于指导后续的零件设计及稳定量产。     

圆盘剪及前后设备对带钢边部质量的影响

在带钢轧制线和精整线上,圆盘剪及其前后设备对带钢的边部质量起着决定性的作用。文章从工艺参数、机械设备和控制要求三方面介绍了提高带钢边部质量的措施。     

ERW焊管辊弯成型过程的动态仿真研究

ERW焊管辊弯成型过程复杂,规律难以把握。为了获得高质量的ERW焊管,减少成型缺陷,降低开发成本,文章采用动力显式有限元法和实验获得材料模型,建立ERW焊管辊弯成型过程的弹塑性有限元模型,实现了对ERW焊管连续成型过程的全流程仿真,分析了带钢在成型过程中的应力、应变变化规律与形状变化规律以及带钢厚度对成型质量的影响。研究结果表明,整个辊弯成型过程应力变化较为平缓,在精成型段有较大变形量,产生较大应力;边部纤维纵向应变高于中部纤维,导致边部有少量"皱曲"产生;随着厚度的增加,纵向应变相应增大。     

工艺参数对简单断面型钢辊弯成型过程的影响

采用B3样条有限条法研究成型工艺参数（如弯曲角增量、带材厚度、材料屈服极限、翼缘长度、腹板宽度和机架间距等）对槽钢辊弯成型过程带材边部纵向薄膜应变峰值的影响。带材边部纵向薄膜应变峰值随着弯曲角增量、带材厚度、材料屈服极限、翼缘长度和腹板宽度增加而增加，随着机架间距的增大而减小。研究结果与辊弯成型过程中观察到的现象完全一致。     

Prediction of maximum initial strip width in the cage roll forming process of ERW pipes using edge buckling criterion

Cage roll forming is an advanced process for producing electric resistance welded (ERW) pipes. It is designed to improve the strip deformation and to increase the flexibility of production lines compared with the conventional roll forming of ERW pipes. One of the most important parameters of this process is the initial strip width. Accurate prediction of the initial strip width is vital for producing sound pipes with desired dimensional and geometrical tolerances. In this paper, cage roll forming process is simulated with the explicit elastic–plastic finite element method in the MSC Marc Mentat software. Simulation results show that by increasing the initial strip width, more circumferential length reduction is induced to the deformed strip in the fin-pass stands. This effect increases the difference of longitudinal strains at the edge and center of the deformed strip and consequently leads to a high longitudinal compression at the strip edge. Therefore, edge buckling will be unavoidable if the initial width is selected bigger than a specific limit. In order to predict the maximum initial width in cage forming process, an edge buckling criterion was introduced. The circumferential length and the horizontal distance between two deformed strip edges were obtained from the simulation and were compared with the experimental data from a production line. The comparison showed a good agreement and confirmed the finite element simulations.     

激光复合织构焊管轧辊模具成形有限元模拟与试验研究

目的提高焊管成形质量,为激光复合织构轧辊模具产业化提供试验依据。方法通过数值模拟方法模拟焊管轧辊成形过程,获得不同摩擦系数组合下板料成形应力应变和径向厚度数据,并获得最优模具表面织构方案,为轧辊模具表面织构处理提供依据。依据数值模拟结果,运用激光表面织构技术对辊子模具表面进行复合织构加工处理,开展激光复合织构模具和未织构模具成形对比,并对成形件进行残余应力、应变、边缘减薄率等检测分析。结果数值模拟结果表明,下辊边缘区域应为减摩区,上辊边缘区域应为增摩区;应对下辊边缘区域进行激光微织构减摩,上辊边缘区域进行激光毛化增摩。成形试验结果表明,试验结果与数值模拟结果基本一致;与未织构模具相比,激光复合织构焊管轧辊模具优化了成形件的应力应变分布,降低了板厚边缘减薄率(5.06%),提高了成形件的均匀性(3.9%),成形件边缘区域形成了残余压应力。结论激光复合织构焊管轧辊模具相比未织构模具,可显著改善成形件的边缘稳定度和成形质量。     

Research on strip deformation in the cage roll-forming process of ERW round pipes

Cage roll forming is an advanced roll-forming technique to manufacture electric resistance welded (ERW) round pipes. In the cage roll-forming process, many small rolls are arranged along the outer surface of the deformable strip to bend the strip edge in a more smooth way. Furthermore, these small rolls can be used for forming pipes of different sizes. Therefore, cage roll forming can reduce roll change time and improve forming quality, as compared with the conventional step roll forming. However, very few studies can be found about cage roll forming, due to its complexity, and the industrial practice depends greatly on experience rather than science-based design today. In this work, the whole cage roll-forming process is simulated with the explicit elastic–plastic finite element method, and the strip deformation during the cage roll-forming process has been investigated in detail. Through the simulation, the “non-bending area” phenomenon is found, and the ranges of the non-bending area at different forming stands are obtained. In addition, the longitudinal strain at the inside edge and center are predicted, and by comparison, it can be known that the deformation of the strip edge is usually larger and edge buckling is most likely to occur at the entry sides of No.1–No.3 fin-pass stands. Finally, the circumferential length, opening distance and the profiles of the deformed strip are measured on the cage roll-forming mill. There is a good agreement between the experimental and simulated results.     

外卷边槽钢多道次辊弯成型数值模拟

利用有限元软件ABAQUS对外卷边槽钢的多道次辊弯成型过程进行了数值模拟。基于动力显示算法,采用引导板料入辊方式建立了外卷边槽钢多道次辊弯成型有限元模型。分析了成型过程中槽钢的金属变形状态与应力应变场的变化情况,并重点研究了外卷边槽钢边部纵向应变、内外弯角处厚度与横向应变在成型过程中的变化情况,为优化多道次辊弯成型工艺提供了理论依据。     

S梁的拉深成形数值模拟

采用数值模拟技术可以在模具设计初期预测产品的成形质量,优化工艺参数,从而缩短模具设计周期,降低成本。基于Dynaform有限元分析软件,对S梁的拉深成形过程进行了数值模拟。针对起皱和未充分拉深等缺陷,提出了压边力和拉深筋工艺参数的改进方案并加以比较,得到了较好的成形模拟结果。试验结果表明：压边力为400kN（不加拉深筋）或300kN（加拉深筋）时成形质量较好。     

Investigation of a new incremental counter forming in flexible roll forming to manufacture accurate profiles with variable cross-sections

A roll-formed profile with variable cross-sections fabricated by flexible roll forming has a shape error, such as warping, because of geometrical deviations in transitional zones of the profile between the initial metal strip and the roll-formed profile. To reduce the shape error, a new process called incremental counter forming (ICF) is proposed. Our investigation of the ICF process shows that the longitudinal strain distribution at the flange of the roll-formed profile can be controlled by combinations of forming parameters of the ICF process. As the forming parameters increase the longitudinal strain distribution in the concave zone, the shape error decreases. However, when the longitudinal strain distribution in the straight zone reaches a critical limit, the additional longitudinal strain works as an excessive longitudinal strain to worsen the shape error. An analytical model, which describes the longitudinal strain at the flange during roll forming, is adopted to reveal that the increase of the longitudinal strain is induced by increasing derivatives of a bending angle, which is controlled by the forming parameters of the ICF process. Finally, the FE simulation has been carried out to compare with the experimental results, which show that the ICF process is effective for reducing the shape error of the profile with variable cross-sections in flexible roll forming.     

COMPUTER AIDED ANALYSIS FOR COLD ROLL FORMING THIN CHANNEL SECTION

1. IntroductionRoll forming is a general term used to describe a large class of continuous manufacturingprocess where a long strip of sheet-metal is deformed illto products with desired geometryby passing through a series of rotating rolls arranged in tandem[1]. A wide range of productsfrom medical equipmellt to office furniture is manufactured in this working method. Sincethe deformation process is complex, cold roll forming, to a large extent, has been developedon an empirical basis and from…     

辊弯成型中的纵向弯曲

纵向弯曲是辊弯成型中存在的普遍现象。由于辊弯成型过程的复杂性,孔型的设计和成型道次数目对纵向弯曲的影响仍然靠经验来确定。利用ANSYS/LS-DYNA软件中的显式动态有限元模块,模拟槽钢辊弯成型过程;并将模拟后的结果与实验数据进行对比;通过改变成型角的尺寸、成型道次的数目和成型底线布置,得到了不同情况下的纵向应变和下弯值,从而找出产品辊弯成型时纵向弯曲的规律,为槽钢辊弯成型设计提供了理论依据。