APPLICATION OF SIMULATION TECHNOLOGY ON THE NON-STEADY METAL FLOW CONDITIONS WITH HOLLOW DIE EXTRUSION

摘要

In recent years, it is useful for the application of various simulations in hot extrusion of aluminum alloys. However, the most of them are generally applied for the field of the steady metal flow conditions with solid die extrusion. In this paper, the simulation technology on the non-steady metal flow conditions with hollow die extrusion is applied. Especially, the effects of the taper porthole shapes on the extrusion pressure-stroke diagrams and the metal flows are investigated experimentally and theoretically. The taper portholes are useful for the reduction of the extrusion pressure by comparison with the straight porthole. Because, the extrusion pressure in porthole filling process is decreased by the reduction of the sliding friction, and the extrusion pressure in welding chamber filling process is decreased by the reduction of strain rate in the porthole and the welding chamber. FEM results by FEM analysis code added especial KNOW-HOW are a close match to the experimental results. Therefore, It is able to predict the extrusion pressure and the metal flow through the porthole and the welding chamber by this simulation technology.