淬火延性钢的屈服行为研究及有限元仿真

发布时间：2018-10-21 16:49

【摘要】：变截面辊弯成型技术是一种节能、顺应轻量化发展的新型塑性成形工艺。但在双相钢板材的成形实验中,成形件变截面区底面腹板因残余应力易产生拱起、边波等缺陷,影响成形精度。本课题针对定模动辊生产线变高度构件制造问题,以减小变形抗力、提高成形精度、优化工艺装备为目标,探究淬火延性钢材料的力学性能、屈服行为和成型仿真,以获得适用于辊弯成型的新高强钢品种。本文依据研究目标,首先针对淬火延性钢QP980材料设计了 30次拉伸实验。通过不同轧制方向的单向拉伸实验获得了该材料的基本力学性能和真实应力应变关系;通过不同轧制方向不同加载比例的双向拉伸实验,得到了双向拉伸下的真实应力应变关系,进而计算出QP980材料的塑性功等高线。本文比较 Mises、Hill'48、Hill'93、Hosford、Gotoh 和 Barlat89 六种常用屈服准则与QP980高强钢屈服行为的匹配程度,得出匹配度最差的是Hosford准则与Barlat89准则,最合适的为Hill'48准则。同时,针对QP980材料对Hill'48准则进行了优化,使之能更好的描述该材料的屈服行为。最后,建立变高度辊弯成型生产线变截面部分的简化模型,同时在材料属性里设置Hill'48准则的相关参数进行有限元仿真,模拟QP980板料通过变高度辊弯成型生产线的成形状况。仿真结果发现板材成形效果良好,没有发现边波、起皱等成形问题。同时在仿真结果中提取数据,分析了等效应力云图、等效塑性应变云图、轧辊反作用力矩、轧辊反作用力、回弹情况,除回弹角度较大外,均能满足变高度辊弯成型生产线的设计要求。实验、理论计算和仿真结果说明QP980高强钢在该生产线上成型具有可行性,可以进行实际成型实验。
[Abstract]:Variable section roll forming is a new type of plastic forming technology, which is energy saving and follows the development of light weight. However, in the forming experiment of duplex steel sheet, the forming accuracy is affected by the defects such as arch and edge wave in the bottom web of the variable cross section zone of the forming part because of the residual stress. In order to reduce the deformation resistance, improve the forming precision and optimize the process equipment, this subject aims at the manufacture of variable height components in the constant die moving roll production line, and probes into the mechanical properties, yield behavior and forming simulation of quenched ductile steel materials. In order to obtain new high strength steel varieties suitable for roll forming. In this paper, 30 tensile tests were designed for quenched ductile steel QP980 materials according to the research objectives. The basic mechanical properties and the true stress-strain relationship of the material were obtained by uniaxial tensile experiments with different rolling directions, and the biaxial tensile tests with different rolling directions and different loading ratios were carried out. The true stress-strain relationship under biaxial tension is obtained and the plastic work contours of QP980 materials are calculated. In this paper, the matching degree of six common yield criteria between Mises,Hill'48,Hill'93,Hosford,Gotoh and Barlat89 and yield behavior of QP980 high strength steel is compared. It is concluded that the worst matching degree is Hosford criterion and Barlat89 criterion, and the most suitable one is Hill'48 criterion. At the same time, the Hill'48 criterion is optimized for the QP980 material to describe the yield behavior of the material better. Finally, the simplified model of the variable section part of the variable height roll bending production line is established. At the same time, the relevant parameters of the Hill'48 criterion are set in the material attribute to simulate the forming condition of the QP980 sheet metal through the variable height roll bending production line. Simulation results show that sheet metal forming effect is good, no side wave, wrinkle and other forming problems. At the same time, the data are extracted from the simulation results, and the equivalent stress cloud diagram, the equivalent plastic strain cloud diagram, the roll reaction moment, the roll reaction force and the springback are analyzed, except for the large springback angle. All can meet the design requirements of the variable height roll bending production line. Experimental, theoretical and simulation results show that QP980 high strength steel forming in this production line is feasible and can be used in actual forming experiment.
【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】：TG142.1

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