Forming process chain for manufacturing complex conical-section profiled rings: On a co-design method

The final quality of complex conical-section rings depends on co-design of multiple processes in forming process chain. In this study, for a complex aeroengine casing ring with a large slope and a flange on its end, a co-design method of the forming process chain is put forward towards the objective of precision forming, which not only proposes a standard process route composed of multiple processes of upsetting, punching, rectangular ring rolling, loose tooling forging and profiled ring rolling, but also presents co-design methods of dies and blanks for all the processes. For profiled ring rolling, a design method of preformed blank that makes the blank and the target conical-section ring have the same axial volume distribution is proposed. By the method, the axial metal redistribution during the process can be alleviated greatly thus improving the forming stability and precision of the ring. Based on the geometric features of designed preformed blank, design methods of blanks and dies for loose tolling forging, rectangular ring rolling, punching and upsetting are proposed sequentially. In view of the key roles of loose tooling forging (manufacturing the preformed blank) and profiled ring rolling on the final quality of the conical ring parts, inherited FE simulations for these two processes are performed to verify the proposed design methods and determine appropriate design parameter. It is demonstrated that the proposed design method has significant advantages in improving forming precision. Besides, a suggestive value 1.5 of the rolling ratio for profiled ring rolling (a key design parameter) is given based on comprehensive consideration of multiple indicators such as ring roundness, deformation uniformity and forming load. The corresponding industrial experiments performed illustrate that a high forming precision of the conical-section aeroengine casing ring is achieved.