Looking at the photo, you can see there is a shape coming out of the exit side of the mill Shape may include stretched edges or center buckle. The operator can see this when operating the mill. Many shape controls are adjusted by the operator at speeds up to 7,000 FPM.
Aluminum has many advantages. The first advantage is that it is light weight or has a low specific gravity. Steel weighs 0.28 pounds per cubic inch. Aluminum weighs one third of steel. If you take the weight of steel and divide by three, you will have the approximate weight of aluminum.
DC motors can do everything AC drives can do, however, the disadvantage of a DC motor is that it requires brushes and these types of motors are open and require some maintenance. Rolling mills usually run around the clock, and DC motors may cause downtime and are expensive to maintain such as the continuous need to be machined, and of course, the brushes wear. However, the amount of maintenance on a DC motor, if maintained properly, can be infinitesimal.
Pure copper is very ductile, which means it has a high elongation. Pure copper can be annealed at 12,000 to 15,000 PSI yield strength, and when reduced or cold worked substantially, can go to 45,000 PSI yield strength.
