Aalco

Recrystallisation

The change in crystal structure of a cold worked metal that occurs when heated through a specific temperature range.

Roll Marks

Periodic surface marks on a work-piece caused by imperfections on the surface of a roll.

Rolled-in Scale

A surface defect caused by patches of scale that were pressed into the surface of the work-piece during rolling.

Roller Levelling

The process of flattening sheet metal by passing it through a roll train of staggered rolls. Levelling is achieved by precisely bending metal strip back and forth as it is passed through a the series of small-diameter offset rolls.

More information: http://www.thefabricator.com/article/coilprocessing/roller-leveling-101