Effect of temperature and friction on necking and thickening for 5A02 aluminum alloy thin-walled tube in differential temperature extrusion
Effect of temperature and friction on necking and thickening for 5A02 aluminum alloy thin-walled tube in differential temperature extrusion
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DOI：
10.1007/s00170-020-05465-w
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发表时间：
2020-05
期刊：
影响因子：
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通讯作者：
Xiaodong Li;X. Xu;K. Wei;Yubin Fan;Li-ming Wei;Zeyu Qui
中科院分区：
文献类型：
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作者：
Xiaodong Li;X. Xu;K. Wei;Yubin Fan;Li-ming Wei;Zeyu Qui
缩口工艺在飞机拉杆零件中得到了广泛的应用。采用传统工艺（如旋压）制造的飞机拉杆零件管端不足以直接螺纹连接，需要铆接螺纹套，导致飞机拉杆零件连接强度低。另外，提出了一种采用差温挤压的薄壁管颈缩和增厚的方法，以直接进行螺纹加工。本文通过有限元模拟和实验研究了5A02铝合金薄壁管缩径增厚过程中温度和摩擦力的影响。模拟结果表明，温度越高，摩擦系数越低，管端增厚区的厚度越大，直接有利于螺纹的加工。通过试验验证了有限元模拟的可靠性。随后，通过光学显微镜研究了温度对成形工件增厚区组织的影响。显微组织形貌表明，在管材缩颈加厚过程中，材料在高温下加热时，与未成形管材相比，成形工件中加厚区域的晶粒尺寸变粗。温度越高，增厚区晶粒越粗。最后，提出了合理的成形温度和摩擦力，以提高薄壁管缩径加厚工艺下飞机拉杆零件的微观和宏观成形质量。
Necking technology was widely used in the airplane pull rod parts. The tube end of airplane pull rod parts made by the traditional technology (such as spinning) was insufficient to thread directly, and it needed to rivet the threaded sleeve, which result in the low joint strength of airplane pull rod parts. Alternatively, a method of necking and thickening for a thin-walled tube using differential temperature extrusion was proposed for the purpose of threading directly. In this work, the effects of temperature and friction during the process of necking and thickening for 5A02 aluminum alloy thin-walled tube were conducted by finite element (FE) simulations and experiments. The simulation results showed that the higher the temperature was and the lower the friction coefficient was, the bigger the thickness of thickening area in the tube end was, which benefited to thread directly. Then, FE simulation was verified to be reliable by experiments. Subsequently, the effect of temperature on the microstructure in the thickening area of the formed workpiece was investigated by the optical microscopy. The microstructural morphology showed the grain size of the thickening area in the formed workpiece coarsened in comparison with the unformed tube when the material was heated at high temperature during the process of necking and thickening of tube. And the higher temperature was, the coarser the grain in the thickening area was. Finally, the reasonable forming temperature and friction was proposed for improving the micro and macro forming quality of the airplane pull rod parts under the necking and thickening process for thin-walled tube.