Fabrication of 2024 aluminum spun tube using a thermomechanical treatment process

The spinning process is considered to be a very effective way for fabricating a long thick-walled motorcase. However, fracture and distortion are often the consequences if the spinning processes and related controlled parameters are not properly set up. A thermomechanical tube spinning process is developed in this study for fabricating 2024 aluminum tubes. The developed process can be outlined in sequential order as annealing, first spinning, solution treatment, second spinning and aging. Optical and transmission electron microscopy (OM/TEM) are employed in the research to reveal the microstructure of the processed material. The results show that annealing and solution treatment can effectively unify the microstructure and recover the ductility of the first spun tube respectively. The high dislocation density induced by the second spinning process makes the precipitates in the aging treatment smaller and more uniform. The thickness and inner diameter of the final tube can be controlled to within 2.4±0.1 and 84.05±0.1 mm, respectively. The tight dimensional tolerance and good strength/ductility demonstrated by the final tube have established that the developed thermomechanical treatment process is feasible and effective.