Shear Stress and Temperature Analysis of Inconel 718 During the Backward Flow Forming Process Using the Finite Element Method

Abstract

Flow forming (tube spinning) is an incremental plastic deformation process that makes it possible to carry out forming operations of metal tubes over a mandrel using enormous forces. During the flow forming process, the rollers apply the radial force, and the machine's headstock unit generates the axial force onto the workpiece. This present work compares the shear stress distribution in all directions. In this study, the finite element method (FEM) is operated to observe shear stress distributions on the workpiece during the flow forming operation. The FORGE® NxT 3.2 and Jmat Pro software are used to reach the most suitable material properties for the process simulation. The annealed condition Inconel 718 material is used for the FEM analyses. Two different reduction ratios, such as 37.5% and 50%, are applied to compare shear stress and process temperature differences in each direction. It is well understood that Arbitrary Lagrangian–Eulerian (ALE) method can be used effectively to predict temperature results of high plasticity processes such as the flow forming process. Furthermore, the re-meshing approach helps reduce simulation times and increase the accuracy during the operation. The results show that the temperature on the workpiece material with a 50% reduction ratio is higher than the 37.5% reduction ratio. Moreover, when the reduction ratio increases, the shear (tangential) stress on the workpiece also increases. In future work, the same forming parameters would be operated on experimental studies to improve and extend the conclusion. It is planned to perform experimental studies with a more detailed comparison by covering stress & strain reaction forces and damage criteria factors to validate FEM results.