Thin aluminum sheet roll
Common quality defects and causes of the thin aluminum sheet roll
1. Non-metallic press-in
Defect: Non-metallic debris is pressed into the surface of the Thin aluminum sheet roll. The surface showed obvious dots or long strips of yellow-black defects.
The main reasons are unclean rolling equipment conditions; unclean rolling process lubricant; insufficient process lubricant injection pressure; scratches on the surface of the slab.
Defects: Bundles (or groups) of scars distributed on the surface of Thin aluminum sheet roll due to relative sliding or misalignment between edges and surfaces, or surface-to-surface contact.
The main reason: Thin aluminum sheet roll produces relative friction and scratches when it comes into contact with the guide path and equipment during the processing and production process; the cold-rolled coil end faces are not aligned, causing misalignment, layer, and layer during vertical furnace annealing and flipping Scratches are generated between them; improper tension during cold rolling, interlayer misalignment during uncoiling and scratches; improper finishing acceptance or packaging operations cause slippage between plates and scratches.
Defects: Scratches on the surface or end of Thin aluminum sheet roll after collision of aluminum plate or aluminum roll with other objects, and most of the metal is extruded at the edge of the recess.
The main reason: the plate or coil collides with other objects during the transportation or storage process; the plate or coil collides with other objects on the annealing rack or the chassis.
4. Warped edge
Defect: After rolling or shearing, the sides of the Aluminum plate sheet are lifted.
The main reasons: excessive reduction during rolling; uneven distribution of lubricating oil during rolling; improper adjustment of the cutting blade during shearing.
Defects: Deformation creases generated after bending the aluminum sheet.
The main reasons: the feeding of the multi-roll straightener is not correct; the thin aluminum sheet roll is unbalanced during turning or handling; the force is unbalanced during stacking.
Defects: The core is severely deformed and the roll shape is not round.
Main reasons: improper tension during the crimping process; external pressure; low core strength; coils without cores are produced by annealing.
7. Split level
Defects: Irregular movement between the strip end surface layer and layer, causing uneven end surface.
The main reasons are uneven billet; improper control of the uncoiling and coiling tension of the rolling mill; the uneven reduction and sleeve movement; improper adjustment of the flattening roller; abnormal centering system during the coiling process; poor roll parallelism.
8. Tower shape
Defect: Thin aluminum sheet roll layer and layer move to one side to form a tower offset.
The main reasons: the poor shape of the incoming material, improper tension control; abnormal coiling alignment control system; weak bonding of the lead during coiling.
9. Loose Roll
Defects: There is looseness between layers during unwinding and unwinding, which may spread to the entire roll in severe cases.
The 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 firm, which occurs during lifting.
10. Bird’s Nest
Defects: Local “V”-shaped defects on the coil end surface. This kind of defect occurs during the winding process of Thin aluminum sheet roll or after unwinding, and some of them are not produced until after a period of time.
The main reasons: improper use of front and rear tension during the coiling process; out-of-round expansion ring or out-of-round bottoming during coiling, resulting from uneven stress distribution after unwinding; poor core quality.
Mingtai Thin aluminum sheet roll:
Mingtai is a large Aluminum Sheet Manufacturer that implements the 6S management system. The product qualification rate is high. Control quality from the source. More than 95% of the key raw materials purchased by Mingtai come from Chinalco Henan International Trading Co., Ltd.
Layer quality inspection on the production line to strictly control the production process; good product performance begins with layered quality supervision.