芯模转速对铸态7075铝合金强力热反旋筒形件壁厚分布的影响

Effect of Mandrel Speed on Distribution of Wall Thickness of Casting 7075 Aluminum Alloy Tube Workpiece during Hot Power Backward Spinning

针对铸态7075铝合金常温下加工塑性较差、晶粒粗大、变形抗力大的特性,本文建立了其强力热反旋成形的三维热力耦合有限元模型。基于ABAQUS/Explicit平台对其成形过程进行了强力热反旋成形数值模拟,并通过试验验证了模型的可靠性。在此基础上,研究了芯模转速对筒形件壁厚不均匀分布的影响,并揭示了相关作用机理。结果表明,强力热反旋是成形铸态7075铝合金薄壁筒形件行之有效的方法之一,当第1、3道次的芯模转速为2 r/s时,壁厚不均匀度取得最小值;第2、4道次的壁厚不均匀度随芯模转速增大而增大。

Aiming at the characteristics of poor plasticity, coarse grain and large deformation resistance of casting 7075 aluminum alloy at room temperature, the three-dimensional thermo-mechanical coupled finite element model of hot power backward spinning was established. The forming process of hot power backward spinning was numerically simulated based on ABAQUS/Explicit platform. The reliability of the model was verified by experiments. On this basis, the effect of mandrel speed on the non-uniform distribution of tube wall thickness was studied, and the related mechanism was revealed. The results show that hot power backward spinning is one of effective methods in forming casting 7075 aluminum alloy tube, and when the die speed of the first and third passes is 2 r/s, wall thickness uniformity is the minimum; and the wall thickness uniformity of the second and fourth passes increases with the mandrel speed increasing.