Study on Spinning Process of a Thin-Walled Aluminum Alloy Vessel Head With Small Ratio of Thickness to Diameter

The thin-walled vessel head with the ratio of thickness to diameter less than 3‰ has long been considered to be difficult to be spun because wrinkling is very likely to occur during the thin-walled vessel head spinning process when the thickness is far smaller than the diameter. Based on process experiments and finite element method, the spinning failure of thin-walled vessel head with a small ratio of thickness to diameter is analyzed in the present research. The mechanism of wrinkling is identified and some effective solutions are discussed to prevent the failure. The results show that the feed ratio, the blank geometry, and the roller trajectory are the main factors influencing the spinning qualities. In the shear spinning, the feasible roller feed ratio is found to be within a very small range because of the thin thickness of blanks. Wrinkling will occur if the feed ratio is slightly outside the operation range. Bending the edge of blank or enlarging the blank size can effectively prevent wrinkling at a larger feed ratio, which would increase the operation range of roller feed ratio. Due to the fact that the conventional spinning is a process of multiple passes, there are many factors affecting the forming quality of thin-walled aluminum alloy vessel head. Wrinkling is likely to happen by the influence of roller trajectory in the first pass due to the fact that the thickness of blank is far smaller than the diameter. The straight-line trajectory is the worst trajectory under which wrinkling is most likely to occur.