Scratch
Definition: A bunch (or a group) of scars distributed on the surface of the plate or belt due to the relative sliding or misalignment of the edges and surfaces between objects, or due to the contact between surfaces.
Main reasons: Wear caused by contact and relative friction between plates and belts and guides and equipment during processing and production; misalignment of the end surfaces of cold rolled coils during annealing and turning in a vertical furnace, resulting in misalignment and wear between layers. Improper cold rolling tension, open roll interlayer misalignment and wear; sliding between plates due to improper surface treatment acceptance or packaging operations.
Abrasion
Definition: Scratches on the surface or end face of an aluminum plate or coil after collision with another object, most of which have metal extrusion at the edge of the depression.
Main reasons: The plate or roll collides with other objects during handling or storage; the plate or roll is produced by colliding with other protruding objects on the annealing material shelf or chassis.
Variable warpage
Definition: When rolling or shearing, the edge of the strip warps.
Main reasons: excessive rolling pressure; uneven distribution of lubricating oil during rolling; improper adjustment of the knife edge during shearing.
