Three-Dimensional Nonlinear Finite Element Analysis of Hot Radial Forging Process for Large Diameter Tubes

A nonlinear coupled finite element model is developed to predict the behavior of large diameter tubes subjected to mechanical and thermal loadings during hot radial forging process. The model is formulated in a three-dimensional (3D) framework to account for both axial and circumferential effects. This model considers both material and geometric nonlinearities. A rate-dependent material model is used to describe the viscoplastic behavior of the workpiece subjected to high temperature and large strain. A tubular workpiece with the mandrel inside and four forging dies outside is modeled in commercial finite element code. A subroutine is developed and implemented to simplify the modeling process for radial forging simulation. Numerical results presented include residual stress, plastic strain, and temperature distribution along the axial and hoop directions in the deformed workpiece. Results are also presented for contact force to evaluate the performance of the die in the forging process. Finite element model predictions are compared with experimental and two-dimensional (2D) axisymmetric simulation results available in literature. A variety of case studies are conducted for hot radial forging process using the developed 3D model.