Experimental Analysis on the Frictional Behaviour of Drawbeads in Sheet Metal Forming

In sheet metal forming, drawbeads are commonly used to control uneven material flow, which may cause defects such as wrinkles, fractures, surface distortion and springback. Although friction may not directly change the limiting strain of steel sheets, the tribological conditions in the contact zone between the sheet surface and the tool surface play an important role in determining the limits of the forming process. Friction in the drawbead contact zones affects the flow of the material in the tool and is used deliberately to control the stamping process. Therefore in this study, the frictional behaviour of drawbeads is experimentally investigated by the drawbead friction test. To characterize the effect of processing variables on the friction coefficients, tests are performed for various sheets, lubricants and bead materials suffering different surface treatments. The results obtained from the drawbead friction test show that the friction and drawing characteristics of deforming sheets were strongly influenced by the strength of sheet, viscosity of lubricant and hardness of bead surface.     

方矩形管连续辊弯成型金属的流动规律

 为了研究方矩形管辊弯成型时金属的流动规律,结合某厂实际生产工艺,建立了方矩形管辊弯成型的三维弹塑性非线性有限元模型,基于该模型得到的仿真结果与现场轧制结果基本一致,通过对仿真结果的分析分别得到了方矩形管辊弯成型时长边、角部、短边和纵向上的内、中、外层的金属流动规律。研究结果表明：在厚度方向稳定段处,从外层到内层的金属流动规律是不一致的,长边处的不一致性要比短边处明显;在纵向上前、中、后段处,外层上的金属流动规律存在较大的差异,前段与后段的外、内层上的金属流动规律是相反的。分析结果为预测最终成型尺寸精度与辊弯成形工艺参数的制定提供了理论依据。     

风管共板法兰辊弯成形过程的有限元仿真

利用通用非线性的ABAQUS软件对多道次辊弯成形过程进行建模以及数值模拟,对辊弯成形工艺及成形规律进行了研究,为辊弯成形的工程设计、工艺参数和辊弯设备的调整提供了科学的依据。整个辊弯成形过程基于动力显式算法,建立风管共板法兰多道次辊弯成形的有限元模型。其中涉及了辊弯成形的模型建立、单元选择、边界条件、有效速度质量放大系数的选择等辊弯成形的一般性问题解决方法。     

Effects of Anisotropy in Drawing and Extrusion Processes of Bulk Metal Forming

The effects of anisotropy of axisymmetric materials (round bars, tubes) on metal forming processes are discussed. These effects are strongest for thin‐walled hollow materials in metal forming processes when the wall thickness is not predetermined by the die (tube drawing without mandrel, free extrusion of hollow components). Similarly to the normal anisotropy of sheet metal, a high radial anisotropy increases the resistance against a variation of wall thickness in tube drawing. There are also effects in forming solid materials such as forward extrusion of bars whereby the buckling of cross sections is influenced through the variation of radial anisotropy with the distance from the axis. The favourable anisotropy properties depend on the actual priorities. If, for example, for a metal forming process the material anisotropy results in high compressive stresses this may be favourable for increasing the ductility of the material whereas the increase of the load acting on the tool reduces tool life.     

热轧张减管青线问题的探讨

青线是热轧无缝钢管生产中主要的外表缺陷之一，在总结长期现场实际生产经验的基础上，对产生青线的种种原因进行了探讨，并针对性提出了预防青线的几点措施，这对同类机组减少青线现象具有一定的参考意义。     

轧机轴承与轧辊智能诊断与维护技术探讨

轧辊与轧辊轴承是轧机的重要部件．智能诊断与维护的主要工作是轧辊与油膜轴承磨损机理研究,人工智能在轧辊与油膜轴承故障诊断与维护的应用,轧辊与油膜轴承远程诊断与维护,轧辊与油膜轴承状态监测与寿命预测．     

圆管二次辊弯成形过程中的大变形有限元法模拟

应用弹塑性三维大变形有限元理论，同时考虑材料和几何双重非线性，基于Ｐｒａｎｄｔｌ－Ｒｅｕｓｓ流动规律和Ｍｉｓｓ屈服准则，并采用Ｕｐｄａｔｅｄ－Ｌａｒｇｒａｎｇｉａｎ增量叠加法分析了不同压下量成形过程中金属由非稳态到稳态的流动规律，然后通过有限元程序实现了计算机模拟。模拟结果为ＣＡＤ（计算机辅助设计）及ＣＡＭ（计算机辅助制造提供了重要理论依据，同时还可以指导实际生产过程，对提高产品的质量和经济效益有     

计算机轧辊管理软件

使用计算机管理轧辊可以非常方便地查询每一条轧辊的材质、产地、车削情况使用情况及该辊的轧制产量等数据，并可根据要求打印表格或轧辊消耗报表。     

Coupling Experiment and Simulation in Electromagnetic Forming Using Photon Doppler Velocimetry

Modeling electromagnetic forming processes is in many ways simpler than modeling traditional metal forming processes. In electromagnetic forming the problem is often dominated by inertial acceleration by a magnetic field. This problem is better posed than the more common ones in metal forming that are often dominated by complex three‐dimensional constitutive behavior and frictional effects. However, important aspects of the problem are dominated by the constitutive properties of the material, and often electromagnetic forming is performed in a regime where there is little reliable material strength data. Strain rates are often high (10² to 10⁴ s^?1 is the typical range for electromagnetic forming). Also, heat is generated both by Joule heating as well as by plastic deformation, and peak temperatures can be quite high. Also, while high‐temperature, high‐strain‐rate data is scarce, there is very little data in cases where temperature rises significantly over very short time periods (tens of micro‐seconds) as in electromagnetic metal forming. This rapid temperature rise is very important to the material response because the short time scales largely preclude the material from recovery and recrystallization processes, and precipitates cannot dissolve as they normally would in an age‐hardening alloy in these time scales. This paper will show how advanced instrumentation, particularly the Photon Doppler Velocimeter (PDV) can be coupled with electromagnetic forming and provide both avenues to characterize the high strain rate strength of the material as well as to provide clear experimentally measured data that can be used to compare experiments with numerical models.     

基于ABAQUS软件的钢卷外铁护圈波浪边辊弯成形数值模拟

通过有限元数值分析软件ABAQUS对外铁护圈的波浪边辊弯成形进行了数值模拟，并研究总结出外铁护圈直径与成形参数之间的关系，揭示了护圈成形的本质规律，为外铁护圈自动成形设备的研发提供了技术基础。     

非圆截面管辊弯成形过程的变形和应力场的FEM模拟

采用三维大变形弹塑性有限元法,考虑材料和几何双重非线性,基于Prandtl-Reuss流动规律和Mises屈服准则,对圆管的辊弯二次成形过程中金属的流动规律及其应力分布进行了模拟分析,分别得到非圆截面管辊弯成形过程中金属的流动规律及应力的信息.     

3000t热矫直机辊系更换的优化与改造

分析辊系更换现状,查找影响辊系更换效率的因素,通过系统地优化辊系更换方案,提升辊系更换效率,大幅缩短了换辊时间。     

Deformation Analysis for the Rotary Draw Bending Process of Circular Tubes: Stress Distribution and Wall Thinning

Rotary draw bending is a CNC tube bending process widely used in industry. Compared with pure bending, rotary draw bending involves a much more complex loading condition. In addition to the bending moment, an axial force is generated in the process even if no drawing force is externally applied. Taking this axial force into account, this paper presents an analysis of tube bending. The stress distribution and wall thinning are calculated. Calculations are compared with experimental and numerical results and a good agreement is shown.     

连铸机远程辊缝调节和辊缝值在线检测

分析了舞钢二炼钢2#、3#连铸机远程辊缝自动调节的控制原理和特点,并介绍了轻压下的基本原理和辊缝值在线检测技术的原理。     

宽带钢热轧机轧辊剥落的控制与效果

轧辊剥落不仅影响轧机的正常生产,而且造成轧辊损坏甚至早期报废。在揭示了轧辊剥落机理的基础上,结合生产实际,采用三维有限元分析,在１７００ｍ ｍ 轧机上采取支持辊新辊形等措施,消除轧辊剥落,实践证明效果显著。     

不锈钢薄带双辊连铸设备的开发

开发了双辊薄带连铸设备和工艺，成功地连铸出厚３～５ｍｍ宽５８０ｍｍ的不锈钢带，简述了铸带的表面质量，铸带的机械性能和耐腐蚀性能。     

热轧厂轧辊磨床数控改造

介绍柳钢热轧厂轧辊磨床的配置方案，数控系统改造内容及实现的控制功能。     

控制轧制与辊型选择

通过改变辊系辊型(支承辊锥度),控制板型、减少轧制道次、提高轧制节凑,进一步提高控制轧制过程中的道次变形程度,从而提高原料收得率、减少计划外、提高产品的综合性能．