Common quality defects and causes of aluminum sheet coil

Common quality defects and causes of aluminum sheet coil



Common quality defects and causes of aluminum sheet coil
1. Non-metal press


Definition: non-metal sundries press into the board and the belt surface. The surface is marked by a yellowish black defect of a dot or a long strip.

Main reason: the rolling process equipment condition is not clean; Rolling process lubricant not quiet; Insufficient injection pressure of process lubricant; The surface of the slab is scratched.

Second, the scratch


Definition: lacuna (or group) of scarring on the surface of a plate or band resulting from the relative sliding or dislocation of the surface of an interfacial edge or surface contact.

Main reasons: when the plate and belt contact with the guide road and equipment during the processing and production, relative friction is generated, resulting in abrasion; The end of cold rolled coil is not even and positive, and there is dislocation and abrasion between layers when the annealing is turned over. The tension during cold rolling is improper, and the interlaminar dislocation occurs when uncoiling. Cleaning acceptance or improper packaging operation caused by sliding between plates caused by abrasion.

Third, bruised


Definition: scratches on the surface or end surface of an aluminum sheet or roll after collision with other objects, and most extruded metals exist at the edge of the depression.

Main reason: the board and roll collide with other objects in the process of transportation or storage; A board, coil, or other projection on an annealing stock or chassis.

Four, become warped edge


Definition: after rolling or shearing, the edge of strip is warped.

Main reason: excessive pressure drop during rolling; The lubricating oil distribution is not uniform during rolling. Improper blade adjustment during shear.

Five, the injured


Definition: a deformed crease formed by the bending of a sheet.

Main reason: the feed is not correct when the machine is straightened with multiple rolls. The force of the sheet is not balanced in turning or handling. The force is not balanced when loading the stack.

Six, flat roll


Definition: the roll is seriously deformed and not round.

The main reason: improper tension in curling process; External compression; Low core strength; Uncoiled coil produced by annealing.

Seven, wrong layer


Definition: the end surface of strip is irregular and staggered between layers, resulting in uneven end surface.

Main reason: the blank is not smooth; Improper control of uncoiling and uncoiling of rolling mill; The pressure is not uniform, and the sleeve runs in series. Improper adjustment of flattening roller; In the process of coiling, the system is abnormal. Bad parallelism of roll system.

Eight, tower

Definition: the coil layer moves to one side to form a tower-like migration.

Main reasons: poor shape of incoming material, improper tension control; Abnormal volume control system; The tape does not bond well when being rolled.

Nine, loose volume


Definition: loose from layer to layer when rolling and unrolling, and sweep the whole volume when serious.

Main reason: the tension during the coiling process is not equal or too small; The pressure of the roller is too low when uncoiling. The steel strip or clip is not firm, which is produced when hoisting.

Ten, the bird's nest


Definition: local "V" type defect on end surface of tape. Such defects occur during the process of rewinding or after unrolling, and some do not occur until a period of time.

Main reasons: improper use of the front and rear tension during the process of winding; The expanding circle is not round or the bottom is not round at the time of winding. Poor core quality.