锥管径向锻造工艺及数值模拟研究

发布时间：2019-01-24 22:30

【摘要】：径向锻造技术在长轴类零件以及具有内部结构的管类零件加工中应用广泛,是一种无屑且精密的金属成形工艺。该工艺可以显著提高材料的塑形,增强零件力学性能,同时具有加工精度高、锻造效率高、材料利用率高、成形质量好等优点。本文以快速导线连接器的重要零件锥形管为研究对象,进行锥管径向锻造工艺与数值模拟研究。锥管两端都为锥形,且内部装配有零件,对内表面质量要求比较高,成形过程中无法加入芯棒,只能通过调整工艺参数,通过外表面变形控制内表面质量。锥管内表面质量的好坏,可以通过锥管厚度变化来衡量,锥管厚度变化越均匀,锥管内表面锥度越好,与内部零件的配合越紧密。针对锥管的成形工艺,本文主要的研究工作包括以下几个方面:基于ABAQUS有限元软件建立了锥管径向锻造二维轴对称模型、三维有限元模型,并对工艺参数进行了优化,将实验结果与模拟结果进行了对比,讨论了多锤头对径向锻造锻件质量的影响,对锥管类零件径向锻造数值模拟进行了分析研究。首先,通过工艺分析,确定了锥管径向锻造成形工艺方案。基于ABAQUS有限元软件建立锥管二维轴对称模型,对轴向送进量、摩擦因数利用单因素变量法分析其对锥管径向锻造锻件壁厚变化的影响。将三维有限元模型中卡爪带动坯料转动转化为公转部件带动锤头绕局部坐标轴转过一个相等的相对角度,改进的模型在保证计算精确度的前提下可以设置更大的质量缩放系数,大大提高了计算效率。将实验结果与模拟结果进行了对比,验证了三维有限元模型的正确性。其次,利用正交试验,研究轴向送进量、旋转角度、摩擦因数对锥管壁厚变化的影响,并以锥管壁厚最大值到未成形端曲线残差平方和的平均值的最小值为优化目标,获得了一组最优的工艺参数组合。另外,分析了锥管直壁段长度对锥管厚度变化的影响,并做实验验证了模拟结果。然后,在相同工艺参数条件下,对比二、三、四锤头对锥管壁厚变化的影响,分析锥管径向锻造过程中应变、最大径向锻打力等信息。最后,基于上述有限元数值模拟结果与实验验证,研究了无法加入芯棒的锥管类零件的径向锻造过程。借助正交试验,研究轴向送进量、旋转角度、摩擦因数、锤头锥角对锥管壁厚变化的影响的显著性,得到了使锥管厚度均匀变化的最优工艺参数组合。利用origin软件拟合出锤头锥角与锥管内表面锥角之间的关系式。
[Abstract]:Radial forging technology is widely used in the machining of long shaft parts and tube parts with internal structure. It is a kind of metal forming technology without chip and precision. The process can significantly improve the shape of the material and enhance the mechanical properties of the parts. At the same time, it has the advantages of high machining precision, high forging efficiency, high material utilization rate and good forming quality. In this paper, the diametral forging process and numerical simulation of the tapered tube, an important part of the fast wire connector, are studied. Both ends of the cone tube are conical and parts are assembled inside the tube. The inner surface quality is very high. The mandrel can not be added in the forming process. The internal surface quality can only be controlled by adjusting the process parameters and controlling the internal surface quality through the deformation of the outer surface. The quality of the inner surface of the cone tube can be measured by the change of the thickness of the cone tube. The more uniform the thickness of the cone tube is, the better the taper of the inner surface of the tube is, and the closer the fit with the internal parts is. The main research work of this paper includes the following aspects: based on the ABAQUS finite element software, the two-dimensional axisymmetric model and three-dimensional finite element model of diametral forging of conical tube are established, and the process parameters are optimized. The experimental results are compared with the simulation results, and the influence of multiple hammers on the quality of radial forging is discussed, and the numerical simulation of radial forging for conical tube parts is studied. Firstly, through process analysis, the process scheme of tapered tube forging is determined. Based on the ABAQUS finite element software, a two-dimensional axisymmetric model of the cone tube is established. The influence of the axial feed quantity and friction coefficient on the wall thickness change of the diametral forging of the cone tube is analyzed by using the single factor variable method. In the three-dimensional finite element model, the claw can drive the billet rotation into a rotating component driving the hammer head to turn around a local coordinate axis at an equal relative angle. The improved model can set a larger mass scaling coefficient under the premise of ensuring the accuracy of the calculation. The calculation efficiency is greatly improved. The correctness of the three-dimensional finite element model is verified by comparing the experimental results with the simulation results. Secondly, the influence of axial feed amount, rotation angle and friction coefficient on the wall thickness of cone tube is studied by orthogonal test, and the minimum value of the maximum wall thickness of cone tube to the mean value of the sum of residual square of unformed curve is taken as the optimization objective. An optimal combination of process parameters was obtained. In addition, the influence of the length of straight wall on the thickness of conical tube is analyzed, and the simulation results are verified by experiments. Then, under the same technological parameters, the effects of two, three and four hammers on the wall thickness of the cone tube are compared, and the information of strain and maximum radial forging force during the forging process of the cone tube are analyzed. Finally, based on the numerical simulation results and experimental verification, the radial forging process of cone tube parts which can not be added with mandrel is studied. The effects of axial feed, rotation angle, friction coefficient and hammerhead cone angle on the wall thickness of cone tube were studied by orthogonal test. The optimal process parameters were obtained to make the thickness of cone tube change uniformly. The relationship between the cone angle of the hammer head and the cone angle of the inner surface of the cone tube is fitted by origin software.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG316

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