1. Non-metal pressing

Definition: Non-metallic debris is pressed into the board, with the surface. There are obvious point-like or long-striped yellow-black defects on the surface.

The main reasons are: the equipment conditions of the rolling process are not clean; the lubricant in the rolling process is not static; the injection pressure of the process lubricant is insufficient; the surface of the slab is scratched.

Second, scratches

Definition: scars distributed in bundles (or groups) on the surface of plates and belts due to relative sliding or dislocation after contact between edges and surfaces, or surfaces and surfaces.

The main reasons: when the plate and strip are in contact with the guide way and equipment during the processing and production process, relative friction occurs and causes scratches; Scratches between the sheets; improper tension during cold rolling, and scuffs due to interlayer dislocation during uncoiling; scuffs due to slippage between plates due to improper finishing acceptance or packaging operations.

3. Bumps

Definition: Scratches produced on the surface or end face of the plate, strip, or end surface after the collision of aluminum plates and coils with other objects, and most of them have extruded metal at the edge of the depression.

The main reasons are: the plates and coils collide with other objects during handling or storage; the plates and coils collide with other protrusions on the annealing rack or chassis.

4. Edge warping

Definition: After rolling or shearing, the edge of the strip is lifted.

The main reasons are: excessive reduction during rolling; uneven distribution of lubricating oil during rolling; improper adjustment of the cutting edge during shearing.

5. Fractures

Definition: Deformation creases produced by sheet bending.

The main reasons: the feeding of the multi-roller straightener is not correct; the force of the sheet is unbalanced during turning or handling; the force is unbalanced when stacking the sheet.

6. Collapse

Definition: The roll core is severely deformed and the roll shape is not round.

The main reasons are: improper tension during the crimping process; external force compression; low core strength; no core coil produced by annealing.

7. Split level

Definition: The irregular dislocation between the end layers of the strip causes the end surface to be uneven.

The main reasons are: uneven billet; improper control of rolling mill uncoiling and coiling tension; uneven reduction, sleeve string movement; improper adjustment of flattening rolls; abnormal alignment system during the coiling process; poor parallelism of the roll system.

8. Tower shape

Definition: The coil layer moves to one side to form a tower-like offset.

The main reasons are: the shape of the incoming material is not good, the tension control is improper; the coiling centering adjustment control system is abnormal; the lead is not firmly bonded during coiling.

9. Loose rolls

Definition: Looseness occurs between layers during winding and unwinding, and in severe cases, it affects the entire volume.

Main reasons: the tension is uneven or too small during the coiling process; the pressure of the pressure roller is too small when uncoiling; the steel belt or clip is not strong, and it is generated during hoisting.