IMMERSION TO ALUMINUM SOLUTION
The Immersion to Solution process is usually applied in air at temperatures between 450 and 575°C, followed by rapid quenching. Cold water, hot water and boiled water (T61 tempering), water-polymer (glycol) solution, water spray or compressed air are used in the cooling process. For 2XXX, 6XXX, 2XX and 3XX alloys, the T4 temper natural aging process is applied at ambient temperature, and the most stable temper is usually only reached after 96 hours. Artificial aging is done at temperatures between 93°C and 245°C, in order to perform T6 and T7X Tempering (Blueing) processes.
After the rapid quenching step immediately after the Immersion to Solution process, all alloys have a relatively soft structure, which can be partially shaped and straightened if machined within a few hours. These alloys are hardened by natural aging at ambient temperature, during which their hardness levels increase gradually, while they also go through the quenching process. If desired, it is possible to shape and straighten the alloy after a few hours of quenching by compressing it by cooling below 0°C. It is cooled to -23°C or below to maintain its quenched tempered state to extend the storage period of several days.
In order to achieve maximum shaping prior to Immersion to Solution and aging processes, the alloys are first prepared for stable, soft O-type tempering by heating at a temperature range of 400 to 425°C and then slowly cooling below 235°C, shaped and then Immersion to Solution and aging processes are applied.