Open die forging technique is mainly used to achieve desired product shape and refine the product mechanical quality. Large ingots tend to... Show moreOpen die forging technique is mainly used to achieve desired product shape and refine the product mechanical quality. Large ingots tend to have internal defects such as shrinkage cavities and porosity, which have to be closed during the primary forging stage to ensure sound internal quality of forged parts. In this work, the finite element method was used to simulate the open die forging process, varying different process parameters that affect the void closure behavior profoundly. Numerical models were constructed in FORGE 2011® using practical forging parameters and material rheological data obtained experimentally from Gleeble compression tests. Forging variables including die design, operational practice and boundary conditions were studied thoroughly. Parameters such as die width, die geometry, die overlap, reduction amount per pass were studied with intense attention paid on the specific mechanical properties of H13 steel, so that this study can be applied to solve real world problems. Also, the temperature gradient and friction condition between billet and die were investigated. Physical experiment validation was carried out with a miniature billet sample. The experiment results were compared with the simulations, showing there was good agreement between the two, giving confidence to the simulation results. Based on the simulation results the optimum forging parameters were proposed to ensure full closure of internal defects. M.S. in Materials Science and Engineering, December 2012 Show less
