共查询到18条相似文献,搜索用时 203 毫秒
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《金属学报》2017,(4)
针对已有板形瓢曲浪形缺陷冷轧高强钢板的淬火过程,应用ABAQUS有限元分析平台及其UMAT二次开发功能,建立淬火过程温度-组织-应力应变多场耦合的有限元仿真模型,研究淬火过程高强钢板的弹塑性变形行为及其对初始板形瓢曲缺陷的改变。通过热模拟实验结果对该有限元仿真模型进行了验证,模拟再现了已瓢曲高强钢板的淬火过程及弹塑性变形,获得了板形瓢曲浪形在淬火过程中的演变规律,指出钢板宽度方向上的温度梯度以及依先后顺序相变所引起的钢板纵向延伸变形沿宽度方向上分布不均匀,导致原有板形瓢曲浪形发生改变,甚至可以生成新的瓢曲浪形。定义了描述板形瓢曲浪形改变程度的指标,如浪高变化率、浪宽变化率、浪距变化率,定量揭示横向温差、张力等工艺参数对冷轧高强钢板淬火过程板形变化的影响规律。搭建实验室冷轧钢板淬火实验研究系统,开展具有单边浪板形瓢曲缺陷钢板的淬火实验,实验结果与仿真计算结果取得定性一致。 相似文献
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针对酸轧联合机组中拉伸矫直机工作辊磨损快、使用寿命偏短等问题进行了理论分析与仿真研究。结合现场热轧带钢来料及工作辊磨损特征,初步推测带钢浪形是引起工作辊异常磨损的主要原因,通过推导边浪带钢延伸率产生的力学机理,验证了浪形带钢对工作辊的切削作用。最后,通过建立有限元模型和工作辊磨损影响因素分析,验证了推测的正确性。 相似文献
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本钢冷轧2150连续退火机组主要生产宽幅汽车外板,具有设计规格跨度大、生产品种多的特点,是国内可提供最宽汽车外板的机组。生产宽幅汽车外板时,瓢曲是连续退火机组上特有的一种缺陷,高温段发生的瓢曲定义为热瓢曲,低温段发生的瓢曲定义为冷瓢曲。文章针对本钢冷轧2150连续退火机组生产薄规格超宽幅汽车外板的瓢曲缺陷的产生机理进行了分析。结合理论及现场实际,对不同瓢曲类型的现场控制方法进行了工艺阐述。通过对炉内张力、带钢温度与炉辊温差等关键工艺参数的优化控制,较好地解决了薄规格超宽料的瓢曲问题。 相似文献
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针对厚度0.2 mm以下极薄规格带钢在生产过程中经常出现中浪缺陷的问题,对某UCM轧机极薄规格带钢局部中浪板形缺陷与轧制过程数据进行了分析,通过工作辊温度测量与工作辊热凸度引起平坦度的有限元计算,表明中浪缺陷是由于轧辊热凸度过大而造成的。分析了轧辊热凸度影响因素,以及UCM轧机轧辊辊型,板形目标曲线,中间辊轴向横移,乳化液,中间辊、工作辊弯辊力等参数对极薄规格带钢板形的影响。结果表明:通过板形目标曲线优化设计,合理配置中间辊轴向横移量、工作辊弯辊、中间辊弯辊3种板形调节手段,增加中间辊轴向横移量,增加工作辊弯辊、中间辊弯辊负弯的调节余量,可在消除中浪的同时避免边浪的产生。同时,通过优化工艺润滑制度,降低乳化液温度到合理范围,可有效提高分段冷却的板形控制能力,使带钢平坦度回归到板形目标曲线设计范围,释放弯辊调控量。再有,通过支撑辊边部辊型优化设计,可提高辊型对边浪的抑制能力,在减少中浪的同时不产生边浪。采用上述措施,将中浪缺陷减小到5 IU以内,极薄规格带钢中浪板形缺陷问题得到了有效解决。 相似文献
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《Journal of Materials Processing Technology》2014,214(2):190-199
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. 相似文献
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纵波轧制+平辊轧制(LFR)是一种减轻镁合金轧制边裂的新型轧制工艺,通过一道次纵波轧制+二道次平轧,可有效减少镁合金板材边裂。为了进一步明晰LFR变形规律,本文通过对比AZ31镁合金板材纵波轧制+平轧(LFR)及平轧+平轧(FFR)热-力耦合有限元虚拟轧制对比和物理实验,分析了纵波轧制变形区金属变形规律及其对板材边部损伤的影响。结果表明:纵波轧制形成了异形搓轧区,板材各部位受到较大的三向剪切作用;急速金属流动产生的塑性变形热避免了板材边部温降,有利于提升塑性;剪切及温度影响促使LFR板材形成混晶组织,降低了波谷部位损伤,进而有效抑制了镁合金板材边裂的产生及发展。 相似文献
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The line array roll set (LARS) rolling process is a new incremental sheet metal rolling process for effective manufacture of doubly curved metal plates. In this study, design equations were developed to predict the curvatures of formed plate shapes with complex curvatures using the experimental data. A series of experiments with various curvatures have been performed. The comparison of the finite element computation results with the design equations has shown that the design equations can be effectively used for process design of forming processes in forming of doubly curved plates over a wide range of input curvatures. 相似文献
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Nonlinear buckling behavior of stiffened composite B–Al plates was analyzed by means of finite element analysis (FEA) method. In the method, the composite material was taken as B matrix into which Al fibers were embedded in different configurations. The laminated B–Al material in the form of rectangular plates was subjected to lateral compressive loading. It is observed that stiffeners have significant effect on the buckling behavior of plates under compressive loading and for various geometrical configurations. The stiffeners used in the modeling are one-sided and have rectangular cross-sections. It is found that there are physically important loading intervals and the critical buckling modes make transitions back and forth between stable and unstable states. Bifurcation buckling regions resulting from various configurations of fiber orientations and different plate aspect ratios are determined. The whole analysis is performed by using ANSYS finite element computations. Only the buckling patterns of stiffened plate configurations under simply supported boundary conditions are studied. Distributions of compressive stresses (σx) vs in-plane contractions (u) and compressive stresses (σx) vs out-of plane deflections (δ) are obtained. Nonlinear analysis of the C2 fiber configuration yields the safest critical buckling stress amongst C1, C2, C3 and C4 configurations. It is concluded that FEA method for the nonlinear buckling analysis generates accurate results. 相似文献
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本文通过实验和有限元模拟对圆板成对无模液压胀形过程进行了研究。在有限元模拟中,分析了初始几何缺陷对壳体起皱的临界压力和起皱形态的影响。结果表明,有限元模拟的带初始缺陷的壳体胀形时的起皱临界压力和起皱形态与实验结果非常吻合,而完善壳体的起皱临界压力和起皱形态与实验结果则有较大差别 相似文献
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冷弯成形工艺参数的设计对冷弯成形产品质量有重要影响。本文对方矩形管冷弯成形过程中机架间距、摩擦因数和轧制速度的不同取值水平通过正交试验设计,利用Abaqus有限元软件的显式非线性动态分析对所设计试验仿真模拟,得到了每道次轧制过程中带钢边部最大纵向应变最小时各个道次3个工艺参数的最佳取值。并用优化后的参数进行仿真和验证,得到各道次带钢边部最大纵向应变比优化前要小,优化后第4~第10道次带钢纵向应变极值相对接近,产品边部拉伸小,并且边部拉伸分布比较均匀,有效改善了产品质量。 相似文献