Aluminum alloy material

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I. Basic properties of aluminum: It has a silver-white color; in humid air, it forms an oxide layer that prevents corrosion of the metal. Its relative density is 2.7 g/cm3, and its melting point is 660°C, with a boiling point of 2327°C. Aluminum is lightweight, possesses good electrical and thermal conductivity, high reflectivity, and resistance to oxidation. II. Types of aluminum products: aluminum profiles, aluminum tubes, aluminum bars, etc. Sheet products: aluminum sheets, aluminum foil, aluminum strips (coils). Casting products: aluminum castings, aluminum pellets. III. Common grades: The first digit of a grade indicates the series to which the aluminum alloy belongs, the second digit shows the degree of modification of the original aluminum alloy, and the last two digits indicate the purity of the aluminum alloy within that series. 1100: Used for manufacturing parts that require good formability and high corrosion resistance, but do not need high strength. Such as storage containers, sheet metal products, deeply drawn concave vessels, heat exchangers, printing plates, nameplates, reflective devices, etc. 2011: High-speed cutting alloy with good cutting properties and high strength, but poor corrosion resistance; suitable for volume knobs, optical components, screw heads, screws, and other machined products that require excellent cutting performance. 3003: It possesses the properties of 1xxx series alloys while offering higher strength than 1xxxx series alloys; it is used in kitchen utensils, devices for handling and storing food and chemical products, tanks and containers for transporting liquid products, as well as various pressure vessels and pipes made from thin sheets. 4A01: High silicon content, heat-resistant and wear-resistant; used as building materials, mechanical parts, forging materials, and welding materials. 5052: The most representative alloy of moderate strength (5083 has the highest strength); it boasts good corrosion resistance, weldability, and formability. In particular, it features high fatigue strength and excellent resistance to seawater. It is used in the manufacture of aircraft fuel tanks and fuel lines, as well as sheet metal components for vehicles and ships, instruments, street light fixtures, rivets, and various hardware products. 6061: A heat-treated corrosion-resistant alloy. Treatment with T6 yields very high endurance values, but the weld joint strength is low; therefore it is suitable for screws, ships, vehicles, and land structures. 6N01: An alloy suitable for extrusion at moderate intensity, capable of producing large thin-walled profiles with complex shapes; it offers good corrosion resistance and weldability. Suitable for vehicles, land structures, and ships. 6063: A representative alloy for extrusion; it has lower strength than 6061 but good extrudability, allowing the production of profiles with complex cross-sectional shapes. It offers excellent corrosion resistance and surface treatment properties, making it suitable for use in construction and road guardrails, vehicles, furniture, home appliances, and decorative items. 7072: It has a low electrode potential and is mainly used for corrosion-resistant coating materials; it is also suitable for heat exchanger fins, aluminum foil in air conditioners, and extremely thin strips. 7075: One of the aluminum alloys with the highest strength, but it has poor corrosion resistance. Using a coating similar to that of 7072 can improve its corrosion resistance, though this increases the cost. Suitable for aircraft, ski poles, thick plates, and forged products. The product requirements are quite stringent; the surface treatment involves coarse brushing or sandblasting. In such cases, 5000-series aluminum alloys are chosen; commonly used ones include 5052. For products with high surface quality requirements—where no sand holes or traces of extrusion are allowed—6000-series aluminum alloys are selected; commonly used ones are 6063/6061. For products where low cost is a priority and re-shaping via stretching is required, 2000-series pure aluminum is used; commonly used is 2011. For applications requiring high strength and hardness, such as load-bearing structures, 7000-series aluminum alloys are utilized; commonly used is 7075.

IV. Surface Treatments
1. Anodizing after sandblasting or brushing
2. Electrophoretic painting
3. Powder electrostatic spraying or fluorocarbon spraying after polishing
4. Electroplating after mirror polishing
5. Wood-grain heat transfer printing
6. Coating with polymer-based PVC film

V. Aluminum Profiles
Aluminum profiles are materials obtained by heating and extruding aluminum rods, resulting in aluminum tubes with various cross-sectional shapes. The molding process mainly consists of five steps: melting and casting, extrusion, cutting, CNC milling, and surface pretreatment and coloring. For specific surface treatment methods, please refer to previous posts: An introduction to metal surface treatment. Titanium plating and electrophoretic coating are the most expensive methods; wood grain thermal transfer and anodizing come next, with spraying being the least expensive. The specific price is subject to the manufacturer’s quote. The main applications of aluminum profiles are as follows: 1. Architectural aluminum profiles (doors, windows, curtain walls); 2. Aluminum profiles for radiators; 3. General industrial aluminum profiles: primarily used in industrial manufacturing, such as in automated machinery and frames, and can be customized through molding. 4. Aluminum alloy profiles for rail vehicle structures: mainly used in the manufacturing of rail vehicle car bodies. 5. Decorative aluminum profiles are used to create aluminum alloy frames for mounting various decorative paintings. 6. Aluminum profiles for exterior use, primarily employed in the home appliance or communications industries, such as in the internal structures and exterior decorations of external hard drives, power banks, televisions, monitors, etc. VI. Aluminum sheets: thin sheets – 0.15–2.0 mm; regular sheets – 2.0–6.0 mm; medium-thickness plates – 6.0–25.0 mm; thick plates – 25–200 mm; extra-thick plates – over 200 mm. Single-layer aluminum sheets can be used for the casings of electronic products, household appliances, or as components for heat conduction within such devices. The finished aluminum casing is produced through three processes: stretching using metal stamping dies, surface pretreatment, and coloring. The forming slope of polymer film aluminum sheets must meet certain requirements; they are difficult to stretch, and the material should be corrosion-resistant, highly weather-resistant, available in various colors, and easy to maintain. Aluminum-plastic composite sheets suitable for use in electronic product casings, household appliance housings, etc., are new types of materials made by combining an aluminum sheet that has been surface-treated and coated with paint as the surface layer, with a mixture of polyethylene and polypropylene plastics as the core layer, through a series of processing steps. It can be used for the decoration of curtain walls, interior and exterior walls, lobbies, restaurants, shops, meeting rooms, etc., as well as for the renovation of old buildings; it serves as a finish layer for counters and furniture, and for the interior and exterior walls of vehicles. Honeycomb aluminum panels feature a composite honeycomb structure, which is formed by thermally pressing pre-formed box-shaped panels and back plates together with an aluminum alloy honeycomb core material. Suitable for decorative applications on building curtain walls, ceiling panels, buses, trains, subways and other rail transit vehicles, commercial transport vehicles and truck bodies, shipbuilding, billboards, and interior decoration projects. Aluminum components are used as decorative casings for products; they feature high tensile strength. The material thickness is usually between 0.4 and 0.8 mm, with grades such as 6063/6061 or pure aluminum being commonly used. A functional enclosure is made of aluminum components; it features bottom stretching and bending structures. The material is usually 0.8–1.2 thick, with harder grades such as 5052/7075, or special grades, being chosen for use. When aluminum components are used in electronic product casings, a laser-etched oxide layer is required followed by conductive grounding, as the oxide layer formed after anodization is non-conductive. VII. Aluminum alloy die-casting: When designing aluminum alloy die-cast parts, try to avoid using inclined ejector mechanisms as much as possible, to prevent difficulties in removing sharp edges and burrs later on. When designing aluminum alloy die-cast parts, it is also necessary to pay attention to ensuring an even thickness of the molten material and a smooth flow of it; this helps to reduce the occurrence of visual defects resulting from the molding process, as well as issues related to subsequent polishing and inspection. If a softer grade of material is chosen, structural strength still needs to be taken into account when designing load-bearing structures; otherwise, they are prone to breaking.