梯度超低温下的铝合金球壳回弹规律研究

doi:10.3901/JME.2025.14.108

摘要/Abstract

摘要： 超低温成形是近年发展起来的一类变革性铝合金薄壁结构成形技术，成形构件尺寸精度受超低温温度分布与复杂应力加载显著影响。重点研究了超低温温度分布对铝合金球壳拉深成形回弹的影响规律；通过变形均匀性与应力解析，揭示梯度超低温对回弹的控制机理。结果表明，球形试件回弹随温度梯度的增大而减小，开口区域尺寸偏差由温度梯度36 ℃的1.35 mm减小为温度梯度216 ℃的0.83 mm，相应尺寸精度可以提高38.5%。这得益于显著提高的应力梯度和变形均匀性。一方面，提高应力梯度可以转移悬空区变形，减小球壳区截面应力差。另一方面，温度梯度增大使变形更均匀，整个试件的壁厚均差率可以提高55.8%，其中，球壳区域的壁厚最大减薄率减小36.9%，法兰区域的壁厚最大增厚率减小74.6%。也就是说，超低温成形不仅能够显著提高成形极限，还能通过温度分布来减小回弹，提高构件尺寸精度。研究结果可为球壳超低温成形精度控制提供指导。

关键词: 铝合金, 超低温成形, 球壳, 回弹, 理论分析

Abstract: Cryogenic forming has been developed into a revolutionary technology for forming alloy thin-walled components recently. The dimensional accuracy of cryogenically formed components is significantly affected by the temperature distribution and complex loading conditions. Therefore, the springback of aluminum alloy spherical shell was studied under different temperature distributions. The control mechanism of gradient temperature fields on springback was revealed through an analysis of deformation uniformity and stress. The results show that the springback of the spherical shell decreases with an increase in the temperature gradient. The dimensional deviation in the opening region decreases from 1.35 mm to 0.83 mm as the temperature gradient increases from 36 ℃ to 216 ℃, showing an enhancement in corresponding dimensional accuracy of 38.5%. This is because of the significantly improved stress gradient and deformation uniformity. On the one hand, stress gradient is increased to transfer the deformation of the unsupported region, and the stress difference is reduced in the spherical shell region. On the other hand, the deformation becomes more uniform as the temperature gradient increases, with the average deviation rate of thickness improved by 55.8% in the entire spherical shell. Among them, the maximum thinning rate in the spherical shell area was reduced by 36.9%, and the maximum thickening in the flange region was reduced by 74.6%. Cryogenic forming can not only significantly improve the forming limit of aluminum alloy but also reduce springback and improve the dimensional accuracy of the components by increasing the temperature gradient. The results can provide guidance for the dimensional accuracy control of spherical shells in cryogenic forming.

Key words: aluminum alloy, cryogenic forming, spherical shell, springback, theoretical analysis

中图分类号:

TG389

邬方兴, 杨光, 王启梁, 凡晓波. 梯度超低温下的铝合金球壳回弹规律研究[J]. 机械工程学报, 2025, 61(14): 108-116.

WU Fangxing, YANG Guang, WANG Qiliang, FAN Xiaobo. Research on Springback of Aluminum Alloy Spherical Shell at Gradient Cryogenic Temperature[J]. Journal of Mechanical Engineering, 2025, 61(14): 108-116.

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