Associate Professor Z.w Chen

Effects of Extrusion Process Conditions on Die Pick-up"": Extrusion Temperature and Extrusion Speed Associate Professor Z.w Chen

In this research AA6060 alloy was used and was extruded at 25m/min, 30m/min, 35m/min, 40m/min and45m/min for a particular profile. The highest exittemperature increased from 542°C to 567°C when theextrusion speed was increased from 25m/min to 45m/min. Three types of die pick-up were identified. They werenamed as normal pick-up, die line pick-up and lumppick-up. Normal pick-up occurred regardless of theextrusion speed and exit temperature; however theamount of normal pick-up did not increase when theextrusion speed was increased. Die line pick-up occurred when the extrusion speed was 45m/min andappeared only on the die lines. Lump pick-up is notsignificant since it was very rare. AA6060 (0.4%Mg and 0.5%Si) alloy has about 0.27% excess silicon and therefore at 555°C, Mg2Siparticles react with aluminium and excess silicon toform liquid. However normal pick-up and die linepick-up still occurred at temperatures lower andhigher than 555°C and therefore it confirms thateutectic reactions do not influence formation of pickup. Therefore die pick-up is most likely to be caused due to a mechanical process ratherthan a metallurgical process.