1 non-metal pressing
Definition: Non-metallic debris is pressed into the surface of the aluminum coil. The surface has obvious dot-like or long strips of yellow-black defects.
The main reason: the equipment conditions in the rolling process are not clean; the rolling process lubricant is not quiet; the process lubricant injection pressure is insufficient; the surface of the slab is scratched.
2 bruises
Definition: A bundle (or group) distribution of scratches on the surface of the board or belt due to the relative sliding or dislocation of the aluminum coil and the ribs and faces or the surface-to-surface contact.
The main reason: aluminum coils are in contact with the guides and equipment during the processing and production, causing relative friction and causing scratches; the end faces of the cold rolled coils are not aligned, and the vertical furnace is annealed and inverted, resulting in a displacement, between layers Scratches are generated; the tension is improper during cold rolling, and interlayer scratches occur during unwinding to cause scratches; improper inspection or packaging operations cause slippage between the plates and cause scratches.
3 bruises
Definition: Scratches on the surface of the plate, belt or end surface after the aluminum plate and aluminum coil collide with other objects, and most of the metal is extruded at the margin of the depression.
The main reason: aluminum plates and aluminum coils collide with other objects during handling or storage; the plates and coils are generated by other protrusions colliding on the annealing rack or the chassis.
4 warping
Definition: After rolling or shearing, the aluminum bead is lifted up.
The main reason: excessive reduction during rolling; uneven distribution of lubricating oil during rolling; improper adjustment of cutting edges during shearing.
5 broken
Definition: Deformation creases produced after bending an aluminum coil.
The main reason: the feeding of the multi-roll straightening machine is not correct; the sheet is unbalanced during the turning or handling; the force is unbalanced when the upper sheet is loaded.
6 collapse
Definition: The aluminum coil core is severely deformed and the roll shape is not round.
The main reason: the aluminum coil is not properly tensioned during the crimping process; the external force is pressed; the core strength is low; and the coreless coil is produced by annealing.
7 wrong layer
Definition: The irregular displacement between the end layer and the layer of the aluminum coil causes the end surface to be uneven.
The main reason is that the aluminum coil blank is not flat; the rolling mill unwinding and the winding tension are improperly controlled; the pressing amount is uneven, the sleeve is strung; the flattening roller is improperly adjusted; during the winding process, the centering system is abnormal; the roller system parallelism is not it is good.
