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.