Aluminum is a silvery-white lightweight metal with ductility. It is commonly manufactured into bars, sheets, foils, powders, strips, and wires. In humid air, it forms a protective oxide film that prevents corrosion. Acid-treated aluminum powder can burn fiercely in the air, emitting a dazzling white flame.

 

Aluminum is soluble in dilute solutions of sulfuric acid, nitric acid, hydrochloric acid, sodium hydroxide, and potassium hydroxide, but it does not dissolve in water. However, it reacts slowly with hot water to form aluminum hydroxide, with a relative density of 2.70/cm³. Its melting point is 660°C, and the boiling point is 2327°C. Aluminum is widely used for its light weight, excellent electrical and thermal conductivity, high reflectivity, and resistance to oxidation.

 

Types of Aluminum Raw Materials

- Extrusion types: aluminum extrusions, aluminum tubes, aluminum rods (solid), aluminum bars (solid profiles), aluminum wires, aluminum welding rods

- Sheet types: aluminum sheets, aluminum foils, aluminum strips (coils)

- Casting types: aluminum castings, aluminum granules

 

Common Grades and Their Applications

- 1100: Used for parts and components that require good formability and high corrosion resistance without the need for high strength. Examples include chemical products, food industry equipment, storage containers, and furniture hardware.

- 2011: A free-machining alloy with good machinability and strength but poor corrosion resistance. Suitable for volume shafts, optical components, screw heads, and mechanical processing products requiring good machinability.

- 3003: Used for parts and components that require good formability, high corrosion resistance, and good weldability, or for applications that also demand higher strength than 1XXX series alloys. Examples include kitchen utensils, food and chemical product processing and storage equipment, transport tanks, and various pressure vessels and pipelines made from thin sheets.

- 4A01: With a high silicon content of 4.5-6.0%, this series is characterized by its heat and wear resistance. It is used in construction materials, mechanical parts, forging materials, and welding materials.

- 5052: A representative alloy of medium strength with good corrosion resistance, weldability, and formability, especially known for its high fatigue strength and excellent resistance to seawater. Used in aircraft fuel tanks, oil pipes, and sheet metal parts for transportation vehicles, ships, instruments, street lamp brackets, rivets, and hardware products.

- 5083: An alloy for welding structures. It is the highest strength corrosion-resistant alloy among practical non-heat-treated alloys, suitable for welding structures with good seawater resistance and low-temperature characteristics. Used in ships, vehicles, low-temperature containers, and pressure vessels.

- 6061: A heat-treatable corrosion-resistant alloy. With T6 treatment, it can achieve very high strength, but the strength of the weld is low. Suitable for screws, hinges, ships, vehicles, and terrestrial structures.

- 6N01: A medium-strength extrusion alloy with strength between 6061 and 6063, good extrudability, and stamping hardenability, suitable for complex shapes of large thin-walled materials, with good corrosion resistance and weldability. Used in vehicles, terrestrial structures, and ships.

- 6063: A representative extrusion alloy with lower strength than 6061 but good extrudability, suitable for complex cross-sectional shapes, with good corrosion resistance and surface treatment properties. Commonly used in construction, highway guardrails, high barriers, and vehicles. It is the most common type used in the production of sofa legs.

- 7072: With a low electrode potential, mainly used as a sacrificial anodic covering material, also suitable for heat exchanger heat dissipating fins, aluminum alloy composite sheet materials, heat dissipating fins, air conditioner aluminum foil, and very thin strip materials.

- 7075: One of the aluminum alloys with the highest strength but poor corrosion resistance. Its corrosion resistance can be improved with 7072 covering materials, but at a higher cost. Suitable for aircraft, ski poles, thick plates, and forgings.

 

Surface Treatment Processes for Aluminum Sofa Legs

1. Sandblasting or brushing followed by anodizing

2. Electrophoretic painting

3. Polishing followed by powder static spraying, fluorocarbon spraying

4. Polishing to a mirror finish followed by titanium plating, titanium-gold plating, or electroplating

5. Various pattern wood grain heat transfer printing

6. High polymer PVC film lamination

 

Forming Process Flow for Sofa Legs

Mold design — Mold making — Stamping forming — Machine processing — Polishing — Surface treatment — Final inspection and packaging

 

Common Grades Used for Sofa Leg Products

- For sofa leg products that require high hardness and a coarse brushed or sandblasted surface, 5000 series aluminum alloys are chosen, commonly: 5052.

- For sofa leg products with high surface treatment requirements, free of pinholes and extrusion marks, 6000 series aluminum alloys are chosen, commonly: 6063/6061.

- For sofa leg products that require a low cost and complex stretching shapes, 2000 series pure aluminum is chosen, commonly: 2011.

- For sofa leg products that require high strength and hardness for load-bearing structures, 7000 series aluminum alloys are chosen, commonly: 7075.

- After structural design is completed, the process specification should indicate the material, material grade, and surface treatment method. For example: Aluminum profile, grade 6063, surface anodized, sandblasted matte finish.