Study On Numerical Simulation Of Continuous Extrusion Formability Differences Between Magnesium Alloy And Pure Aluminum Sheets

Magnesium and aluminum are light alloy structural materials, their application has been sped up increasingly with structural lightweight technology needs and environmental issues. The problems of existing forming process of magnesium and aluminum sheet are parameters strict, multi-channel processing and high cost, etc. Continuous extrusion technology is a kind of plastic forming methods which is high efficient and energy saving, it has been applied to manufacture copper sheets successfully. So the study on the continuous extrusion extending deformation of magnesium and aluminum is important. However, their plastic deformation is different for the crystal structure of the magnesium and aluminum is different, which affects the technology making and mold design on continuous extrusion process about the two metals, therefore, it is necessary to carry out a comparative study of the continuous extrusion extending deformation of magnesium and aluminum sheet.The numerical simulation of continuous extrusion forming process (CONFORM) of the magnesium alloy and pure aluminum was carried out based on DEFORM-3D.The extending forming characteristics of the two materials were analyzed. The effects of the extrusion wheel velocity, product dimensions, and channel length of metal flow and preheating temperature of tools on the forming regularity with the similarities and differences between the two materials were discussed. The reference is provided for the technology making and mold design on continuous extrusion process about magnesium and aluminum. The results showed that:(1) The temperature distribution presented reduced form the center of the expansion chamber to both sides gradually. The velocity difference of AZ31magnesium alloy in the expansion chamber is larger, and the thermal conductivity of AZ31magnesium less than pure aluminum, resulting in the temperature gradient of AZ31magnesium alloy is larger and maldistribution.(2) The flow non-uniformity of AZ31magnesium alloy and pure aluminum increase for the extrusion wheel velocity increasing and product width broadening and product thickness thinning. AZ31magnesium alloy has poor plasticity in continuous extrusion due to the crystal structure, and its flow non-uniformity performance obviously.(3) The temperature field is more uniform of the two materials and expansion chamber when the temperature of preheating temperature of tools is400℃.(4) The AZ31magnesium alloy sheet is uniformity with port hole structure of circular after the optimization of the flow path, the velocities of the two materials increase with the extrusion wheel velocity increasing on the surface, the middle surface, the lower surface along the plate thickness direction. (5) The extrusion wheel velocity of AZ31magnesium alloy should less than9r/min, and the extrusion wheel velocity of pure aluminum can be increased to11r/min. The effects of channel length of metal flow on the flow uniformity of pure aluminum obviously, the torque of extrusion wheel of the two materials are stabilized when channel length of metal flow increases from50mm to continue.