U形AZ31镁合金温热张力绕弯成形的工艺研究
发布时间：2018-11-17 12:59
【摘要】：轻量化弯曲型材成形技术是先进塑性加工技术发展的趋势,薄壁镁合金弯曲件应用于航空航天、交通运输等行业具有减重、降低能耗等优势。AZ31镁合金的室温成形性能较差,采用传统弯曲成形方法不能保证弯曲件成形质量及尺寸精度。本文采用温热张力绕弯成形,通过改善温度加载模式、加热型材、添加预拉伸的方法使型材在热-力作用下提高其弯曲性能。回弹和工艺参数优化是AZ31镁合金型材温热张力绕弯成形亟待解决的问题。本文采用理论分析、有限元模拟及实验研究相结合的方法,对AZ31镁合金型材的温热张力绕弯成形工艺进行研究,分析了温度、预拉伸量等工艺及材料因素对型材绕弯成形性的影响规律。本文研究内容和结论如下:采用Gleeble-3800热模拟实验机对AZ31挤压态镁合金型材进行拉伸实验,获得AZ31镁合金流动应力应变关系;采用MSC.Marc软件,建立镁合金温热变形模型,建立三维弹塑性热-力耦合有限元模型,通过模拟温度加载模式、不同绕弯成形温度及不同预拉伸量,分析绕弯过程的应力应变场、温度场,获得优化的U形挤压态AZ31镁合金型材的绕弯成形工艺参数及工艺条件;并进行AZ31镁合金型材的温热张力绕弯成形实验。模拟及实验结果表明,工艺参数对回弹的影响规律一致。采用局部加热型材的方式,将型材加热至170℃,在型材端部添加0.2%的预拉伸量,保持端部张力的添加将型材绕弯110°后卸载,可以得到回弹量较小、表面起皱少的U形AZ31镁合金绕弯成形件。绕弯过程中弯曲温度的升高,可以减小型材的回弹,但温度升高到170℃以上,绕弯成形性较好,其弯曲变形量较大,易发生减薄;随着预拉伸量的增大,其回弹量一开始降低,继续增大预拉伸量,对回弹量不发生显著变化;随着弯曲角度的增大,型材弯曲成形性能变差,到110°以上,型材内壁易发生畸变。
[Abstract]:Lightweight bending profile forming technology is the development trend of advanced plastic processing technology. Thin wall magnesium alloy bending parts are used in aerospace, transportation and other industries, such as weight reduction, energy consumption reduction, etc. AZ31 magnesium alloy has poor room temperature formability. The traditional bending method can not guarantee the forming quality and dimensional accuracy of bending parts. In this paper, the bending behavior of the profile is improved by improving the temperature loading mode, heating the profile and adding pretension. Springback and optimization of process parameters are the urgent problems of AZ31 magnesium alloy profile forming. In this paper, theoretical analysis, finite element simulation and experimental study are used to study the forming process of AZ31 magnesium alloy profile by thermal tension winding, and the temperature is analyzed. The influence of pretension and material factors on the bending formability of profile. The main contents and conclusions of this paper are as follows: the flow stress-strain relationship of AZ31 magnesium alloy was obtained by using Gleeble-3800 thermal simulation machine to carry out tensile test on AZ31 extruded magnesium alloy profile; Using MSC.Marc software, the thermal deformation model of magnesium alloy is established, and the three-dimensional elastic-plastic thermo-mechanical coupling finite element model is established. By simulating the temperature loading mode, different bending temperature and different pretension amount are simulated. The stress and strain field and temperature field of the bending process are analyzed, and the optimized forming process parameters and process conditions of U-shaped extruded AZ31 magnesium alloy profile are obtained. The forming experiment of AZ31 magnesium alloy profile by thermal tension winding was carried out. The simulation and experimental results show that the effect of process parameters on springback is consistent. By heating the profile to 170 鈩，
本文编号：2337868
[Abstract]:Lightweight bending profile forming technology is the development trend of advanced plastic processing technology. Thin wall magnesium alloy bending parts are used in aerospace, transportation and other industries, such as weight reduction, energy consumption reduction, etc. AZ31 magnesium alloy has poor room temperature formability. The traditional bending method can not guarantee the forming quality and dimensional accuracy of bending parts. In this paper, the bending behavior of the profile is improved by improving the temperature loading mode, heating the profile and adding pretension. Springback and optimization of process parameters are the urgent problems of AZ31 magnesium alloy profile forming. In this paper, theoretical analysis, finite element simulation and experimental study are used to study the forming process of AZ31 magnesium alloy profile by thermal tension winding, and the temperature is analyzed. The influence of pretension and material factors on the bending formability of profile. The main contents and conclusions of this paper are as follows: the flow stress-strain relationship of AZ31 magnesium alloy was obtained by using Gleeble-3800 thermal simulation machine to carry out tensile test on AZ31 extruded magnesium alloy profile; Using MSC.Marc software, the thermal deformation model of magnesium alloy is established, and the three-dimensional elastic-plastic thermo-mechanical coupling finite element model is established. By simulating the temperature loading mode, different bending temperature and different pretension amount are simulated. The stress and strain field and temperature field of the bending process are analyzed, and the optimized forming process parameters and process conditions of U-shaped extruded AZ31 magnesium alloy profile are obtained. The forming experiment of AZ31 magnesium alloy profile by thermal tension winding was carried out. The simulation and experimental results show that the effect of process parameters on springback is consistent. By heating the profile to 170 鈩，
本文编号：2337868
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