Residual stress and flatness defects in sheet metal strips

typical coil defects

Typical coil defects are shown in the figure above. Most common defects are coil set and cross bow.

Coil set is caused by the plastic deformation during the coiling process. The cross bow, however, is caused by the irregular cooling down of the rolling stock across the entire coil width.

In summary, coil defects are usually caused by the rolling process itself or by subsequent cutting processes.