Reverse rolling forming method for Ti2AlNb-based alloy special-shaped ringpiece

The invention discloses a reverse rolling forming method for a Ti2AlNb-based alloy special-shaped ring piece. The method is characterized in that a special-shaped part is reversely designed, wherein in the rolling forming process, the material of a special-shaped part of a ring blank flows to a main part of the ring blank, the material of the main part of the ring blank flows reversely, a special-shaped part of the ring piece is formed, and a formed forging streamline is good; the size of the ring blank and the size of the ring piece meet the formulas that D =(1-k)d , D =(1-k)d , H =(1-k)h and H =(1-k)h ; and the deformation of each part of the ring piece is ensured to be consistent, and k is controlled between 25% and 40%. By means of the method, one-fire forming can be realized in the rolling process, the cost is saved to a great extent, the production period is shortened, and the obtained ring piece is uniform in structure, good in performance and good in consistency. The method is suitable for roll formin