The quality of solution annealed and age hardened aluminium resp. aluminium alloys increases strongly with temperature uniformity as well as with the speed of heat transfer. For thatreasons liquid salts are the first choice. They are well known for their excellent temperature constancy and provide:

• Quickest heat transfer by contact which successfully oppressed grain growth for gaining a very fine core structure.
• Avoidance of deleterious precipitation of alloying elements on grain boundaries since the remaining salt film on the parts prevents from critical cooling effects during transfer into quenching station.
• Shortest treatment times