关键词: 铝合金, 金属旋压, 预成形, 热处理, 残余应力

Abstract: In order to prolong the service life of repeatable rocket, the effects of pre-deformation and heat treatment processes on the residual stress of 2219 aluminum alloy spinning thin-walled structure in the manufacturing process of rocket tank bottom were studied.. Based on Abaqus software, a spinning simulation model considering pre-deformation and heat treatment is established. The simulation results of stress and deformation are transmitted by pre-defined field, and the blind hole method is used for experimental verification. Comparing the spinning simulation results with or without pre-deformation process, it is found that the strain in the middle region of the “pre-deformation + spinning” part is more uniform, the wall thickness changes less, and the thinning rate is reduced by 5.2%. This is due to the pre-forming effect, the deformation of the subsequent spinning process is reduced, and the deformation of the spinning process is more stable. Without pre-deformation process, a stress ring composed of stress concentration areas is observed at the outer edge of the “single spinning” parts, and the maximum residual stress value is 173.9 MPa. By contrast, the stress ring of the “pre-deformation + spinning” parts is affected by the pre-deformation process induced stress. The maximum residual stress is increases by 41.3%, up to 245.7 MPa, but the stress ring distribution is more uniform and the width decreases, and the stress concentration area is refined. Subsequently, heat treatment was applied to the “pre-deformation + spinning” parts. The results show that heat treatment has no significant effect on strain and thinning rate, but the residual stress after spinning can be significantly reduced by 63.5%, which is helpful to alleviate the stress concentration caused by spinning and homogenize the residual stress distribution.

Key words: aluminum alloy, metal spinning, pre-deformation, heat treatment, residual stress