External pressure forming of thin walled W-shaped sealing rings in aircraft engines using movable dies

Hydroforming is an effective method for manufacturing complex and thin walled parts. In order to develop a forming process of complicated thin walled superalloy W-shaped sealing rings, a technology scheme is proposed consisting of external pressure forming using movable dies and its finite element model is built. The deformation rule and destabilization mechanism are discussed at different forming stages. Moreover, the effects of key process parameters, including the heights of blank forming area and loading paths of cavity pressure on the quality of the parts, are explored with the assistance of numerical simulations and verification experiments. Furthermore, the failure modes during the forming process, including wrinkling in the circumferential direction, configurational asymmetry and accumulation folding are discussed, while the technological parameters are optimized. The results indicate that the proposed technological method is feasible for the accurate integral forming of W-shaped sealing rings; moreover, the parts with smooth surfaces and high quality can be successfully formed using optimal parameters.