The influence of the MRE forming medium and axial feeding on the forming quality of thin-walled Inconel 718 bellow manufactured by a bulging process: finite element simulation and experimentation

Abstract

Manufacturing thin-walled metallic bellow is a complicated forming process, and defects such as wrinkling, cracking, and over-thinning quickly occur because of the complex compressive and tensile stress state. To achieve high-quality products, it is crucial to study the forming characteristics and explore proper forming parameters in advance for a particular metallic bellow. Thus, this investigation is aimed at studying the effect of using the magnetorheological elastomer (MRE) forming medium and the axial feeding on the forming quality of thin-walled Inconel 718 bellow during the bulging process. The change of MRE’s mechanical properties is combined with the basic principle of the bulging process. The process of coupling three different axial loading paths and three magnetic field loading conditions was explored through finite element (FE) simulation. The results obtained from the FE simulation showed that the forming quality of the proposed thin-walled bellow is the best when the magnetic field intensity is 0.14 T, and the punch step length is 7 mm. The experimental results are in a remarkable agreement with those obtained from simulation, confirming the simulation’s validity.