Analysis of the causes of several common aluminum plate defects and defects

- Nov 14, 2018-

Simply introduce several common aluminum plate defects and have a better understanding of aluminum plates.

1. Shape of the plate:

(1) Staggered layer: irregularly displaced between the end face layer and the layer, causing the end face to be uneven. Cause: the billet is not flat; the rolling mill unwinding, the winding tension is not properly controlled; the flattening roller is not properly adjusted.

(2) Collapse: The core of the coil is severely deformed, and the roll shape is not round. Cause: Improper tension during crimping; external force is oppressed.

(3) Lateral bending: the shape of the plate is curved to one side. Cause: The leveling machine is not pressure enough.

(4) Wave: A general term for various unevenness phenomena formed by aluminum sheets and aluminum strips due to uneven deformation. The wave generated by the plate and the edge is called the edge wave, the wave generated in the middle is called the middle wave, and the wave between the middle and the edge which is neither in the middle nor on both sides is called the two-rib wave, which is small in size and usually The circular waves are called broken waves. Cause: The roll gap adjustment is unbalanced, the roll type control is unreasonable; the lubrication and cooling are uneven, and the aluminum plate is unevenly deformed; the distribution of the pass reduction is unreasonable.

2, size:

(1) Thickness tolerance: tolerance of ±1% below 1.0, above ±5% of 1.0, single out of tolerance*2 times;

(2) Width tolerance: ±0.1MM below 3.2MM, ±0.2MM above 3.2MM;

(3) Length tolerance: +5-3MM. The cause of the thickness tolerance, the problem of the thickness gauge; the cause of the width tolerance, the disc shear adjustment is not suitable; the cause of the length tolerance, the adjustment of the shearer is problematic.

3. Surface:

(1) Embossing: chromatic aberration caused by irregular chromatic aberration of the roll surface due to strip wrinkles, broken strips, etc., periodically printed on the surface of the strip during rolling.

(2) Scratch: It is characterized by a bundle of scars on the surface of the aluminum plate. Cause: Mechanical or manual causes the aluminum plate to create a layer-to-layer displacement.

(3) Warping: After rolling or shearing, the edge of the strip is lifted.

(4) Corrosion: It is characterized by white spots or black spots on the surface of the aluminum plate. Cause: Acid, alkali or water is introduced during production, packaging, transportation and storage.

(5) Surface oil stain: It is characterized by dirt on the surface. Cause: The cooling oil is dirty and the air blow is weak.

(6) Scratch: It is a flaw with a line on the surface of the aluminum plate. Cause: The guide plate or the flat roll has convex or sticky aluminum; scratches occur during the shearing process; manual inspection is improperly carried out.

(7) Side bending: The longitudinal sides of the plate and the belt exhibit a non-flat state of bending to one side. Cause: The rolling amount at both ends of the mill is not the same; the thickness of the plate and the material on both sides are inconsistent.

(8) There are black spots on the surface: the surface of the aluminum plate has needle-like black spots. Cause: The furnace fluid is not clean.

4. Mechanical properties:

(1) The hardness is not enough. Cause, material/component, heat treatment process.

(2) Stamping cracking, hard or soft. Material or status issue.

(3) Other defects: water ripples after oxidation, black and white road; surface dark flowers; surface is not bright.