Mechanical Defects

Friction Gouges (hot)

Caused by laps sliding against each other. When still in coil form, gouges are often created when uneven side walls are pushed flat when the coil is laid on its side. Gouges created when the coil is still hot will be dull in appearance.

Friction Gouges (cold)

Often created when laps slide against each other during coiling/uncoiling and rebanding of a coil, or when the coil strikes an outside surface. Gouges created when the material is cold will be bright and shiny. The distinguishing feature of a friction gouge is a flattened ball of displace steel – material gets gouged out and rolled back into the surface.

Scratches

A foreign object comes into contact with the surface creating a linear defect parallel to the rolling direction. Scratches can also be caused by rubbing against a mechanical surface.