Design of forging process parameters with deformation and temperature constraints

This paper presents a methodology for designing optimal process parameters for forging operations. The nonlinear rigid viscoplastic finite element (FE) method is used for deformation and thermal analyses. From the FE model a state space system is developed for representing the coupled deformation and thermal behavior of the metal forming system. Constraints are imposed on the strain rate and temperature of the deforming workpiece for obtaining the desired physical/microstructural properties in the final product. The linear quadratic regulator (LQR) theory for finite time control is used in designing the initial die temperature and optimal ram velocity schedules. The approach is demonstrated on a plane strain channel section forging under nonisothermal conditions.