The influence of cooling conditions after homogenisation and preheating conditions to extrusion temperature have been investigated on AA 6063 and AA 6082 aluminium alloys with regard to the Mg2Si particle development and their effect on flow stress at the extrusion temperature and hot ductility as well as hardness after ageing. Both continuous and isothermal cooling (stepcooling) were investigated in combination with fast induction heating and slow gas heating of the billet prior to extrusion.