Coils are cooled down and then undergo cold rolling below the recrystallization temperature to be made thinner.
Purposes of cold rolling
Increased strength and hardness by strain hardening
Finer grain structure
Precise thickness control
Better surface quality
Coil Degreasing Line
Process for removing the rolling oil from the surface of the cold rolled coil to prevent defects
During cold rolling, aluminum is hardened and becomes less rollable. So, cold rolled aluminum needs to be heated to recover its ductility at appropriate temperatures. This process is called annealing. Annealing of expandable non-heat treatable alloys is classified as either process annealing (which is done in the course of cold rolling in order to adjust the strength of the final products), final annealing (which is done after cold rolling in order to obtain O-temper or H2X-temper alloys), or stabilizing annealing (which is done to produce H3X-temper alloys).