What are the reasons for the common quality problems of aluminum coil and aluminum plate?

Various quality problems will appear in the production process of aluminum sheet metal and aluminum sheet roll. What are the reasons for the quality problems? Here is a brief introduction:

1. Non metallic press in

Main reasons: the equipment conditions of the rolling process are not clean; rolling process lubricant is not quiet; insufficient injection pressure of process lubricant; there are scratches on the slab surface.

2. Scratch

Main causes: when the plate and belt are in contact with the guide and equipment during processing and production, they produce relative friction and cause scratch; the end face of cold rolled coil is not aligned, resulting in dislocation and scratch between layers during annealing turnover in vertical furnace; improper tension during cold rolling and scratch caused by interlaminar dislocation during uncoiling; scratches caused by sliding between plates due to improper finishing acceptance or packaging operation.

Scratched and spotted a metal aluminium sheet

3. Bruise

Main causes: the plate and coil collide with other objects during handling or storage; the plate and coil are caused by the collision of other protrusions on the annealing rack or chassis.

4. Edge warping

Main reasons: excessive reduction during rolling; uneven distribution of lubricating oil during rolling; improper adjustment of cutting edge during cutting.

5. Fracture

Main reasons: incorrect feeding during feeding of multi roll straightener; the stress of a thin plate is unbalanced during turning or handling; when stacking the sheets, the force is unbalanced.

6. Collapse roll

Main reasons: improper tension during crimping; external pressure; low core strength; coreless coil is produced by annealing.

7. Staggered layer

Main reasons: the blank is not flat; improper control of uncoiling and coiling tension of rolling mill; the reduction is uneven and the sleeve moves in series; improper adjustment of flattening roller; during coiling, the centering system is abnormal; poor parallelism of the roll system.

8. Tower shape

Main reasons: bad shape of incoming sheet and improper tension control; the coiling alignment control system is abnormal. The head is not firmly bonded during coiling.

9. Loose roll

Main causes: uneven or too small tension during coiling; the pressure of the pressing roller is too small when uncoiling; the steel belt or clip is not firm, which occurs during hoisting.

10. Bird's nest

Main reasons: improper use of front and rear tension during tape coiling; the expansion ring is not round or the backing is not round during coiling, which is caused by the uneven distribution of stress after coiling; poor core quality.