(1) Metallurgical quality
The melt must be fully deslagging, degassing, filtering and grain refinement. The internal structure of the cast (ingot) rolled plate is not allowed to have defects such as air channels, slag inclusions, segregation and coarse grains. The hydrogen content of the melt is required to be controlled below 0.12mL. (100g)-, the non-metallic slag inclusions do not exceed 10X10-6, and the grain size of the cast rolled plate is first grade.
(2) Surface quality
The surface should be clean and flat. There should be no pine branch marks, pressure scratches, scratches, holes, corrosion, warping, oil spots, metal or non-metal additions, etc. These defects will directly affect the surface quality of the aluminum foil.
(3) End face quality
The end face trimming should be flat. There should be no burrs, cracks, layer cross-linking, bruises, etc. Burrs, cracks, and bruises will cause frequent strip breakage and strip roll-off during rolling. Layer cross-linking will affect the plate shape control and the trimming quality of re-rolling.
(4) Billet thickness and width deviation
To ensure the thickness tolerance of aluminum foil, the longitudinal thickness deviation of aluminum coil should not exceed ±5% of the nominal thickness (high-precision rolling mills can control it within ±2%). The width deviation is a positive tolerance, generally required to be no greater than the nominal width of 3mm. If the thickness of the aluminum coil fluctuates greatly, it will inevitably cause the thickness of the aluminum foil to fluctuate greatly, and in severe cases, it will cause folding defects.
(5) Plate shape
The transverse cross-section of the billet is parabolically symmetrical, the convexity is no more than 0.5%~1%, and the wedge-shaped thickness difference section shape is no more than 0.2%. For cold rolling mills equipped with automatic plate shape control systems, the online plate shape of the billet is no more than ±10I.
(6) Mechanical properties
The selection of mechanical properties of aluminum coils is mainly based on the type and performance requirements of the aluminum foil products produced. Typical mechanical properties of aluminum coils are shown in the table below.
| Typical mechanical properties of aluminum coils | |||
| Alloy grade | State | Tensile strength δ/MPa | Elongation δ/%(≥) |
| 1070~1060 | 0 | 60~90 | 20 |
| H14 | 80~140 | 3 | |
| H18 | ≥120 | 1 | |
| 1145 1235 | 0 | 80~120 | 30 |
| H14 | 130~150 | 3 | |
| H18 | ≥150 | 1 | |
| 3003 | 0 | 100~150 | 20 |
| H14 | 140~180 | 2 | |
| H18 | ≥190 | 1 | |
