超高强度钢辊弯成形工艺变形机理分析

发布时间：2018-04-02 07:18

本文选题：辊弯成形　切入点：超高强度钢　出处：《北方工业大学》2017年硕士论文

【摘要】：辊弯成形技术能够生产高强度、性能佳、高精度的型钢产品,并且具有高效、节能、省材等特点,在汽车、建筑等领域得到广泛运用。本文采用解析法、有限元模拟以及实验等方法对超高强度钢辊弯成形变形机理展开研究。本文建立了超高强度钢辊弯成形ABAQUS有限元仿真模型,通过对比实验工件和模拟工件的最终截面尺寸,验证了有限元模型的准确性;考虑了纵向弯曲应变对最终纵向应变值的影响,解析分析了超高强度钢辊弯成形板材纵向应变,修正了计算纵向应变理论公式,并通过数值模拟和实验验证了解析结果,仿真和实验结果表明,解析计算得出的纵向应变值和实验所得纵向应变值误差为5E-4。本文阐述了辊弯成形变形机理,辊弯成形过程是板材重复进行加载-卸载的受力过程,板材在经过各道次轧辊后,各单元结点的等效应力发生阶段性释放。所以辊弯成形工件的回弹是由于多道次弹性应力逐次释放引起的,,而工件最终成形是多道次总塑性应变累积的结果。针对超高强度钢辊弯成形件的回弹缺陷,提出了控制回弹的成形工艺方法。本文分析两种轧辊设计方案,板材下弯角处的应力、应变场,结果表明,实弯能够有效增大弯角区的塑性变形,增大等效塑性应变值,提高辊弯成形件精度,成形件弯角区的板材的变厚情况得到明显改善,使板材下弯角区材料流动更加合理。对比轧辊改良前后,成形板材的成形精度得出改善,优化后成形件的回弹角度最大误差为1.66%。
[Abstract]:Roll forming technology can produce high strength, good performance, high precision steel products, and has the characteristics of high efficiency, energy saving, saving materials and so on, and has been widely used in automobile, building and other fields. The deformation mechanism of ultra-high strength steel roll bending forming is studied by finite element simulation and experiment. In this paper, the ABAQUS finite element simulation model of ultra high strength steel roll bending forming is established, and the final cross section dimensions of experimental workpiece and simulated workpiece are compared. The accuracy of the finite element model is verified, the effect of longitudinal bending strain on the final longitudinal strain is considered, the longitudinal strain of sheet metal formed by ultra-high strength steel roll bending is analytically analyzed, and the theoretical formula for calculating longitudinal strain is revised. The analytical results are verified by numerical simulation and experiments. The results of simulation and experiment show that the errors between the calculated longitudinal strain values and the experimental longitudinal strain values are 5E-4. The deformation mechanism of roll bending forming is described in this paper. The forming process of roll bending is the process of repeated loading and unloading of sheet metal. After the plate passes through each pass of roll, The equivalent stress of each unit node is released in stages. Therefore, the springback of the roll formed workpiece is caused by the successive release of the elastic stress, and the final forming of the workpiece is the result of the accumulation of the total plastic strain of multiple passes. Springback defects of roll bending forming parts of ultra-high strength steel, This paper analyses two kinds of roll design schemes, the stress and strain fields at the lower corner of sheet metal. The results show that the actual bending can effectively increase the plastic deformation in the corner zone and increase the equivalent plastic strain value. By improving the precision of roll bending forming parts, the thickening of sheet metal in the corner zone of forming parts is obviously improved, which makes the material flow more reasonable in the lower corner zone of sheet metal. Compared with the improvement of roll, the forming accuracy of forming sheet metal is improved. The maximum error of springback angle is 1.66.
【学位授予单位】：北方工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG306

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