楔横轧多楔成形铝合金连杆坯料的数值模拟分析

发布时间：2018-01-21 21:53

本文关键词： 楔横轧多楔成形铝合金连杆坯料数值模拟　出处：《广西大学》2016年硕士论文　论文类型：学位论文

【摘要】：连杆是发动机中最重要的部件之一,对发动机的正常工作起关键作用。但因连杆零件形状复杂,其质量与坯料质量的分配、金属纤维流线的连续性和分布密切相关,传统的制坯工艺不易精确控制坯料的质量分配、难以保证金属纤维流线的连续、均匀分布,生产率不高、机械化程度低等问题,严重影响了连杆的质量和产量。楔横轧制坯在提高坯料形状尺寸精度、表面质量、综合力学性能以及生产率等方面具有更明显的优势,这对追求优质、高效、节材的连杆生产具有重要的指导意义。本文首先运用刚塑性有限元理论进行楔横轧多楔成形铝合金轴类件的有限元数值模拟分析,并与真实实验结果进行对比,结果表明有限元模拟结果和真实实验结果基本一致。说明,本文利用刚塑性有限元理论进行数值模拟分析方法是准确可靠的。在此基础上,选用高强度铝合金作为生产原材料,对楔横轧多楔成形铝合金连杆坯料进行了模拟研究,探索其变形、缺陷产生机理,并分析了工艺参数对缺陷的影响,为后续模锻成形连杆提供质量保证,为铝合金连杆的生产提供借鉴。主要研究结论如下：(1)轧件上的金属流动研究表明：心部金属流动慢,表面金属流动快,轧件中间细杆部网格被严重压缩、拉长、扭转,容易产生缩颈、心部缺陷；轧件端部容易产生凹心缺陷；(2)应力应变研究表明：中间细杆部形变大,细杆部中间段心部应力应变较大,晶格畸变大,位错密度高,容易产生疏松、缩孔等心部缺陷,适当提高轧制速度、侧主楔成形角,或适当降低内侧楔展宽角有利于减轻心部缺陷；(3)影响堆料形成的主要因素是金属流动的速度和位移方向。金属流动的速度和方向与轧辊的轧制速度、断面收缩分配系数、成形楔的斜面(成形角)有关,通过选择合适的轧制速度,适当降低断面收缩分配系数、侧主楔和内侧楔成形角有利于减轻轧件大头末端的堆料。
[Abstract]:The connecting rod is one of the most important components in the engine, which plays a key role in the normal operation of the engine. However, because of the complicated shape of the connecting rod parts, the quality of the connecting rod is distributed with the quality of the blank. The continuity and distribution of metal fiber streamline is closely related to the traditional billet manufacturing process is not easy to accurately control the quality distribution of blank, it is difficult to ensure the continuous and uniform distribution of metal fiber streamline, the productivity is not high. The low degree of mechanization has seriously affected the quality and output of the connecting rod. The cross wedge rolling billet has more obvious advantages in improving the shape and size accuracy, surface quality, comprehensive mechanical properties and productivity of the blank. This is of great significance to the production of high quality, high efficiency and low material connecting rod. Firstly, the finite element simulation analysis of multi-wedge forming aluminum alloy shafts with cross wedge rolling is carried out by using rigid-plastic finite element theory. Compared with the real experimental results, the results show that the finite element simulation results are basically consistent with the real experimental results. In this paper, it is accurate and reliable to use the rigid-plastic finite element theory to carry out numerical simulation analysis. On this basis, high-strength aluminum alloy is selected as raw material. In this paper, the simulation study of aluminum alloy connecting rod billets for cross wedge rolling is carried out, and the mechanism of deformation and defect generation is explored, and the influence of process parameters on defects is analyzed to provide quality assurance for subsequent die forging forming connecting rod. The main research conclusions are as follows: the metal flow on the workpiece is slow, the surface metal flow is fast, and the meshes in the middle of the workpiece are seriously compressed. Elongate, torsion, easy to produce necking, heart defects; The center defect is easy to be produced at the end of the rolling piece. 2) the study of stress and strain shows that the center part of the middle part of the thin bar is deformed, the center part of the middle part of the thin bar is large in stress and strain, the lattice distortion is large, the dislocation density is high, and the center defects such as porosity and shrinkage are easy to be produced. Increasing rolling speed properly, forming angle of side main wedge, or decreasing width angle of medial wedge are helpful to alleviate center defect. The velocity and direction of metal flow are related to the rolling speed of roll, the distribution coefficient of cross section shrinkage, and the inclined surface (forming angle) of the forming wedge. By selecting the appropriate rolling speed, reducing the cross section shrinkage distribution coefficient properly, and the forming angle of the main wedge and the inner wedge of the side, it is helpful to reduce the material stacking at the end of the large end of the rolling piece.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG339

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