Effects of processing parameters on the extrusion by continuous variable cross-section direct extrusion with 7A09 aluminium alloy

摘要

In order to study the effects of processing parameters on the continuous variable crosssection direct extrusion (CVCDE), taking 7A09 aluminium alloy for example, the extrusion speed and forming temperature and the friction factor as key processing parameters are applied to research by finite element (FE) simulation. The research result showed that the extrusion speed had a significant influence on the maximum temperature of the billet, at the same time, both decreasing the friction factor and increasing forming temperature within a certain range were beneficial to reduce extrusion load. Both forming temperature and the extrusion speed were inversely linked to extrusion load, but the friction factor was directly proportional to extrusion load. Forming temperature had a far more important influence on extrusion load by comparison: when forming temperature increased from 380 to 430 degrees C, the peak value of extrusion load decreased by 25.6% and the flow uniformity of extruded product got improved. The process window based on both the press limit and surface defects limit was established and the most reasonable forming temperature was 405 degrees C under this process condition, which provided theoretical basis for formulation process of 7A09 aluminium alloy on the CVCDE extrusion.