Processing Defects
Double Breaks
Caused by shearing clearances, and more prevalent on thicker material and higher carbon grades which are generally more difficult to slit/shear. Double breaks are more commonly on the ID of a slit coil, because before the strip can be pulled with tension the slitting knives are not as perfectly straight.
Annealing Burn
O Annealing burn or stain is caused by exposure to oxygen or moisture while the steel is at high temperatures (300F+). This can happen when annealing bases are uncovered before sufficient cooling.
Coolant Stain
Rust spots caused by the insufficient removal of coolant during cold rolling.
Roll pick up
A depression caused by loose scale or other particles "picking up" on the rolls as they pass over the surface. The adherent particle leaves a depression every rotation for as long as it is stuck to the roll. If the depression repeats throughout the coil, it can also be called a roll mark.
Roll marks
A depression in the surface caused by a foreign particle on the roll. The depression will repeat at a consistent interval that matches the diameter of the roll multiplied by pi.
Coil breaks
Also called cross breaks. They are caused by discontinuous yielding in soft steels.
Pickle stain
A rust stain caused by the improper drying in the tanks.
Pits
A general term for depressions in the surface of the steel.