Effects of Extrusion Process Conditions on “Die Pick-Up”

In this research AA6060 alloy was used and was extruded at 25m/min, 30m/min, 35m/min, 40m/min and 45m/min for a particular profile. The highest exit temperature increased from 542C to 567C when the extrusion speed was increased from 25m/min to 45m/min. Three types of die pick-up were identified. They were named as normal pick-up, die line pick-up and lump pick-up. Normal pick-up occurred regardless of the extrusion speed and exit temperature; however the amount of normal pick-up did not increase when the extrusion speed was increased. Die line pick-up occurred when the extrusion speed was 45m/min and appeared only on the die lines. Lump pick-up is not significant since it was very rare. AA6060 (0.4%Mg and 0.5%Si) alloy has about 0.27% excess silicon and therefore at 555C, Mg2Si particles react with aluminium and excess silicon to form liquid. However normal pick-up and die line pick-up still occurred at temperatures lower and higher than 555C and therefore it confirms that eutectic reactions do not influence formation of pickup. Therefore die pick-up is most likely to be caused due to a mechanical process rather than a metallurgical process. Robbie Peris was brought up in Sri Lanka and migrated to New Zealand in 2002. He obtained his BE(Hons) and ME(Hons) from AUT University Auckland New Zealand. He did his Masters Thesis with Fletcher Aluminium. Currently Robbie Peris is working as a Research Officer at AUT University and is part of the metal forming group.