铸造铝合金筒形件多道次强力热反旋椭圆度研究

发布时间：2018-01-13 18:11

本文关键词：铸造铝合金筒形件多道次强力热反旋椭圆度研究　出处：《南昌航空大学》2015年硕士论文　论文类型：学位论文

【摘要】：高强铸造铝合金筒形件是广泛应用于航空、航天、化工、船舶、汽车、兵器等领域的一重要的回转体类零件。多道次旋压成形是成形此类零件的主要方法之一。然而该成形是一个涉及多场、多因素耦合作用的复杂变形过程,如果成形过程中成形参数控制不当就会导致椭圆等缺陷,严重影响成形质量。因此,本文基于ABAQUS有限元并结合理论与实验研究系统地分析成形参数对高强铸造铝合金筒形件多道次强力旋压椭圆度的影响规律。主要研究内容和结果如下:(1)解决了几何模型、材料模型的建立以及边界条件和网格划分等筒形件强力热反旋有限元模型的关键技术,基于ABAQUS平台建立了符合实际又兼顾计算效率计算精度的筒形件旋压成形的有限元模型,并通过实验研究验证所建立的有限元模型的可靠性。(2)基于所建立的有限元模型,分析铸造铝合金筒形件旋压过程中不同道次应力应变分布规律,提出了工件椭圆度的量化描述,获得了椭圆度随旋压进程的产生、发展、演化规律。结果表明:在三向应力变化不均匀区域,工件椭圆度明显增大;旋压区附近椭圆度最大。工件椭圆度随着旋压进程逐渐增大,且增大速度逐渐趋于平缓,椭圆度趋于稳定;各道次趋于稳定的临界进程随着道次增加而推后,第一道次在旋压进程到40%后椭圆趋于稳定,第四道次要旋压到80%后椭圆才稳定(3)基于所建立的有限元模型,系统地研究了铸造铝合金筒形件多道次热反旋成形参数(温度、进给速度、摩擦、主轴转速等)对椭圆度变形的影响。发现:随着主轴转速的增加,工件椭圆度先减小后增大;摩擦系数对工件各道次椭圆度的影响有所差异,但总体呈增大的趋势;随着进给速度的增大,各道次工件椭圆度的总体趋势是先增大后减小,呈抛物线的变化;椭圆度随着预热温度的升高而增大,预热温度对工件椭圆度的影响在第四道次最为明显。
[Abstract]:High-strength casting aluminum alloy cylindrical parts are widely used in aviation, aerospace, chemical industry, ships, automobiles. The multi-pass spinning is one of the main methods of forming such parts. However, the forming is a complex deformation process involving multi-field and multi-factor coupling. If the forming parameters are not controlled properly in the forming process, it will lead to defects such as ellipse, which will seriously affect the forming quality. Based on ABAQUS finite element method and theoretical and experimental study, this paper systematically analyzes the influence of forming parameters on the ellipticity of high strength casting aluminum alloy cylinder. The main contents and results are as follows. :. (. 1) the geometric model is solved. The establishment of material model and the key technology of boundary condition and mesh division are discussed in this paper. Based on the ABAQUS platform, the finite element model of spinning forming of cylindrical parts is established, which accords with the practice and takes into account the calculation accuracy. The reliability of the established finite element model is verified by experiments. (2) based on the established finite element model, the distribution of stress and strain of different passes in the spinning process of casting aluminum alloy cylindrical parts is analyzed. A quantitative description of the ellipticity of the workpiece is presented, and the rules of the ellipticity generation, development and evolution with the spinning process are obtained. The results show that the ellipticity of the workpiece increases obviously in the region of uneven stress variation in three directions. The ellipticity of the workpiece increases gradually with the spinning process, and the increasing speed tends to be gentle, and the ellipticity tends to be stable. The critical processes of each pass tend to be stable with the increase of the number of passes, and the ellipse of the first step tends to be stable after the spinning process reaches 40%. Based on the established finite element model, the parameters (temperature, feed velocity, friction) of multi-pass thermal reverse spinning for casting aluminum alloy cylindrical parts are systematically studied. It is found that with the increase of spindle speed, the ellipticity of workpiece decreases first and then increases; The influence of friction coefficient on the subellipticity of workpiece is different, but the overall trend is increasing. With the increase of feed speed, the general trend of the ellipticity of each pass workpiece is to increase first and then to decrease, with the change of parabola. The ellipticity increases with the increase of preheating temperature, and the influence of preheating temperature on the ellipticity of workpiece is most obvious at 4th pass.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG306

【相似文献】