Design Of Mold And Research On Technological Experiments Of Hydrostatic Extrusion For Aluminum Alloys

Hydrostatic extrusion is a new type of extrusion processing technology which uses high pressure liquid medium to induce hydrostatic compressive stress on the billet, thus to achieve material extrusion deformation. Compared with the conventional direct extrusion, hydrostatic extrusion has such unique advantages as, no flattened cylindrical appeared, nearly zero friction, low extrusion pressure, etc. The extruded products can obtain high surface quality and excellent mechanical properties.Firstly, the hydrostatic extrusion and conventional extrusion process were simulated by FEA software ANSYS/LS-DYNA. The influences of die angles and extrusion ratios on the stress, strain, and extrusion pressure were compared. The optimized die angle was determined, which can provide basis for the design of hydrostatic extrusion die.Secondly, based on the characteristics of hydrostatic extrusion process and principles of die design, the hydrostatic extrusion mold for aluminum alloy extrusion products was designed. The results of numerical simulation and theoretical calculated extrusion pressure were compared. For the key components of the mold, the die and the container were optimized and strength checked.Finally, by using the self-designed extrusion mold,1060 aluminum alloy were extruded at room temperature under different extrusion ratios conditions, and specific solutions were given for the view of the problems appeared in the experimental process. The maximum strain values of the outer extrusion cylinder were measured by strain gauge paste technology, in order to ensure safety of experiment and prevent damage of the container. By view of eyes, the extruded rods were smooth and straight. The microstructure and mechanical properties analysis results showed that with the increased extrusion ratio, the grain size reduces, the strength and hardness increase and the work-hardening rate decreases. Compared with the unextruded billet, the micro-hardness and yield strength of hydrostatic extruded ones, under the extrusion ratio of λ=9, had been improved by nearly 117% and 390% respectively.