Multi-stage hydro-mechanical deep drawing of complex thin-walled superalloy parts

Hydro-mechanical deep drawing (HDD) is an effective method for manufacturing thin-walled parts. In order to develop a forming process of complicated thin-walled superalloy parts, an analysis is made of the wrinkling and destabilization in the free areas of the conical wall of a workpiece, based on which a technology scheme is proposed consisting of multi-stage HDD assisted by conventional deep drawing, and its finite element models are built. The effect of key process parameters, including pre-forming depth and finishing forming 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 and fracture, are discussed, while the technological parameters are optimized. The results indicate that the proposed technological method is feasible for the integral forming of complex thin-walled superalloy parts with large drawing ratios; moreover, parts with uniform thickness distribution and high quality can be successfully formed by using optimal pre-forming depths and finishing forming cavity pressures.