Method and equipment for cooling on a reversing hot rolling mill

A process for hot rolling an AA6xxx series aluminum alloy with a hot reversing mill, the hot reversing mill comprising a top work roll and a bottom work roll, and at least one cooling system intended to cool a blank, said blank moving on reels and passing through the hot reversing mill between the top and bottom work rolls and, said cooling system consisting of two cooling devices:

• a top cooling device of the blank and a bottom cooling device of the blank wherein the top cooling device comprises at least one bar of nozzles disposed parallel with the axis of the top work roll, the nozzles spraying with jets of cooling fluid the top face of the blank, the bottom cooling device comprises at least one bar of nozzles disposed between reels or between the bottom work roll and a nearest reel, parallel with the axis of the bottom work roll, the nozzles spraying, with jets of cooling fluid, the bottom face of the blank, the axis of the jets of cooling fluid being oriented substantially perpendicularly to the bottom surface of the blank, the process comprising:
• a. casting a rolling ingot made of AA6xxx series alloy,
• b. homogenizing the rolling ingot, optionally followed by a reheating,
• c. first hot rolling to convert the rolling ingot into a blank having a first output thickness from a first hot rolling starting temperature,
• d. cooling the blank obtained with a mean cooling rate of the mean temperature of the blank of V=C/e up to a second starting temperature of second hot rolling, where V is in ° C./s, e is the thickness of the blank in mm, and C is a constant which equals between 400 and 1000° C./s*mm, optionally between 600 and 900° C./s*mm, more optionally between 700 and 800° C./s*mm,
• e. second hot rolling to convert the blank obtained into a strip at the final hot rolling thickness under deformation and temperature conditions such that the strip is recrystallized to at least 50%,
• f. cold rolling the strip into a sheet.