宽幅镁合金薄板大压下轧制温度场变化规律的研究

发布时间：2018-04-23 13:40

本文选题：宽幅AZ31 + 大压下轧制　；参考：《燕山大学》2015年硕士论文

【摘要】：航空、航天、武器装备、大型船舶和高速列车的轻量化需求对宽幅镁合金板材及其组合件代替钢板和塑料的需求量将越来越大,因此开发大尺寸宽幅镁合金板材具有重要的战略意义。镁合金板带轧制是研究变形镁合金中的重要方向,以较高的轧制温度来进行大压下率轧制,使镁合金在轧制中产生完全动态再结晶,以此来得到组织均匀细小和力学性能优良的产品,这样既提高了生产效率,又降低了生产成本,具有比较高的现实意义。且温度是镁合金板带轧制过程中最重要的工艺参数,直接影响着轧制时金属的动态再结晶过程以及塑性变形机制,从而影响其最终组织和性能。因此研究板带在轧制过程中的温度变化和内部温度分布规律是保证轧制成品质量的前提。在轧制过程中,有必要调整并且控制好轧制温度以此来得到符合性能要求的成品。本课题的研究目的就是运用实验法以及数值模拟法对宽幅镁合金薄板大压下率轧制过程中温度场的变化规律进行研究。利用Gleeble-3800热模拟试验机,进行高温压缩热模拟实验,得到流变应力曲线,为后续有限元软件模拟轧制过程以及理论分析提供可靠数据支持。并且进行平面应变压缩实验,模拟轧制过程。通过金相试验,测试在不同压下率以及轧制温度下轧制后试样的组织变化规律,得到镁合金的最佳轧制工艺参数。运用MSC.Marc建立三维轧制模型对镁合金薄板轧制过程轧制温度、压下率、轧辊预热温度以及板带宽度等不同工艺参数进行数值模拟,初步探析研究镁合金轧制较适合的压下率。然后分析大压下率轧制过程中温度场沿板带宽度方向的变化规律,研究镁合金板带轧制过程中的传热机理,建立温度模型以对镁合金热轧进行最优温度控制。针对轧制过程中板带边部温降的现象,并改善由于边部温降引起的边裂问题,提出板带边部感应加热来达到边部温度回升,对板带边部温度进行补偿,并建立电磁热耦合模型来分析边部温度变化。
[Abstract]:The demand for lightweight aerospace, aerospace, weapons, large ships and high-speed trains will be increasing for wide-width magnesium alloy sheets and their assemblies instead of steel plates and plastics. Therefore, the development of large-size and wide-width magnesium alloy sheet has important strategic significance. The rolling of magnesium alloy strip is an important direction in the research of wrought magnesium alloy. With high rolling temperature, the rolling of magnesium alloy can produce complete dynamic recrystallization. In this way, the products with fine and uniform structure and excellent mechanical properties can be obtained, which not only improves the production efficiency but also reduces the production cost, so it has higher practical significance. The temperature is the most important technological parameter in the rolling process of magnesium alloy sheet and strip, which directly affects the dynamic recrystallization process and plastic deformation mechanism of the metal during rolling, thus affecting the final microstructure and properties. Therefore, it is the premise to study the temperature change and internal temperature distribution in the rolling process to ensure the quality of the finished product. In the process of rolling, it is necessary to adjust and control the rolling temperature to get the finished product. The purpose of this paper is to study the variation of temperature field in the process of high reduction rate rolling of wide magnesium alloy sheet by means of experimental method and numerical simulation method. The flow stress curve is obtained by using Gleeble-3800 thermal simulation machine to simulate the high temperature compression heat, which provides reliable data for the subsequent finite element software to simulate the rolling process and theoretical analysis. And the plane strain compression experiment was carried out to simulate the rolling process. By means of metallographic test, the microstructure changes of the samples after rolling at different reduction rates and rolling temperatures were measured, and the optimum rolling process parameters of magnesium alloys were obtained. The rolling temperature, reduction rate, roll preheating temperature and strip width of magnesium alloy sheet were numerically simulated by MSC.Marc. The suitable rolling rate of magnesium alloy rolling was studied. Then, the variation law of temperature field along the width of strip during high reduction rate rolling is analyzed, the heat transfer mechanism in the rolling process of magnesium alloy strip is studied, and the temperature model is established to control the optimal temperature of hot rolling of magnesium alloy. In view of the phenomenon of temperature drop on the edge of the strip during rolling, and to improve the edge crack caused by the temperature drop of the edge, it is put forward that the induction heating of the edge of the strip is used to recover the temperature of the edge, and the temperature of the edge of the plate is compensated. An electromagnetic-thermal coupling model is established to analyze the temperature variation of the edge.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG339

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