Hot rolled aluminum strip is an aluminum alloy strip produced through a hot rolling process. The production process typically involves heating aluminum ingots to a high temperature and then rolling them through a rolling mill to produce aluminum strips of the required thickness. Its core advantages are low cost, good toughness, and adaptability to thicker specifications.
Production process of hot rolled aluminium strips:
- Raw material preparation:
Electrolytic aluminum ingots with a purity ≥99.0% are selected, or elements such as manganese, magnesium, and silicon are added according to the alloy formula. The melting temperature is controlled at 700℃-750℃ to ensure uniform composition.
- Ingot treatment:
After casting, the large ingots (typically 400mm-600mm thick and 1000mm-2200mm wide) require homogenization annealing for at least 48 hours to eliminate internal stress. The surface is milled to a thickness of 5mm-15mm to thoroughly remove the surface oxide layer and casting defects.
- Hot rolling:
The slab is heated to 480℃-510℃ (close to the recrystallization temperature of aluminum) and rolled using a two- or four-high reversible hot rolling mill. The roughing pass reduces the thickness by approximately 30%-50%, and the finishing pass reduces it to 10%-20%, gradually thinning the slab to the target thickness.
- Subsequent processing:
After rolling, the slab is cooled online (air-cooled or water-cooled), controlling the cooling rate to prevent excessive grain size. It is then coiled into standard steel coils with an inner diameter of 508mm or 610mm using a coiler. Some products require straightening and edge trimming to remove burrs.
Alloy series of hot rolled aluminum strips:
- 1xxx series (Pure aluminum):
Such as 1060 (99.6% aluminum content), 1070 (99.7% aluminum content), with an electrical conductivity ≥60% IACS and excellent thermal conductivity. Mainly used in electrical applications such as transformer windings and cable shielding.
- 3xxx series (aluminum-manganese alloys):
Such as 3003 (containing 1.0%-1.5% manganese) and 3004 (containing 1.0%-1.5% manganese + 0.8%-1.3% magnesium), exhibit corrosion resistance far exceeding that of pure aluminum, and can be directly used for outdoor decoration and air conditioner heat exchanger fins.
- 5xxx series (aluminum-magnesium alloys):
Such as 5052 (containing 2.2%-2.8% magnesium) and 5083 (containing 4.0%-4.9% magnesium), with yield strengths reaching 170MPa-280MPa, good toughness, and suitable for stamping, used in automotive body structural components and ship decks.
- 6xxx series (aluminum-magnesium-silicon alloys):
Such as 6061 and 6063, can be strengthened through heat treatment, balancing strength and machinability, and used for mechanical parts and building profile blanks.
- Specifications:
Thickness generally ranges from 0.1mm to 4mm, and width from 100mm to 2600mm. Customization is available upon request.
Performance parameters of hot rolled aluminium strips:
- Mechanical properties:
Tensile strength ranges from 100MPa to 300MPa (depending on the alloy), elongation ≥15% (over 30% for 1-series alloys), hardness HB30-HB80.
- Surface quality:
Slight oxidation and roller marks may appear on the surface after hot rolling. Roughness Ra≤1.6μm, requiring subsequent pickling or polishing to achieve decorative grade requirements.
- Dimensional accuracy:
Thickness tolerance is ±0.05mm-±0.5mm (larger tolerances for thicker alloys), width tolerance is ±2mm-±5mm, straightness ≤3mm/m.
- Corrosion resistance:
3xxx series and 5xxx series aluminum alloys can withstand marine climates and industrial environments. 1xxx series aluminum grades are prone to oxidation in humid environments and require surface coating protection.
Hot rolled aluminum strip has the following characteristics:
- Good plasticity:
Due to processing at high temperatures, aluminum strip has good plasticity, making it easy to form and process.
- Wide size range:
Hot-rolled aluminum strip can be produced in wider and thicker sizes, suitable for various applications.
- Good mechanical properties:
Hot-rolled aluminum strip typically possesses excellent mechanical properties, making it suitable for structural applications.
- Surface treatment:
The surface of hot-rolled aluminum strip is relatively rough, usually requiring further surface treatments such as pickling and anodizing to improve its corrosion resistance and aesthetics.
Applications of hot rolled aluminum strips:
- Industrial manufacturing:
Base material for aluminum foil (e.g., food packaging foil, battery foil), stamped automotive engine cylinder head gaskets, gearbox housings.
- Construction:
Anodized curtain wall decorative strips, roof waterproofing membranes (aluminum strip and rubber composite), door and window frame substrates.
- Electronics and power:
Aluminum strip for transformers (1060 material), lithium battery electrode substrate (3003 material), shielding layer for wires and cables.
- Other fields:
Corrosion-resistant steel plates for ships, medical device housings (5052 material), and furniture and decorative accessories.
