Series 1: Features: Contains more than 99.00% aluminum, good electrical conductivity, good corrosion resistance, good weldability, low strength, cannot be strengthened by heat treatment. Application range: High-purity aluminum (aluminum content above 99.9%) is mainly used in scientific experiments, the chemical industry, and special purposes.
Series 2: Features: Aluminum alloys with copper as the main alloying element. Manganese, magnesium, lead, and bismuth may also be added to improve machinability. For example, 2011 alloy requires safety precautions during melting. 2014 alloy is used in aerospace, with high strength. 2017 alloy has slightly lower strength than 2014 alloy but is easier to process. 2014 can be strengthened by heat treatment. Disadvantage: Pronounced tendency for intergranular corrosion. Application range: Aerospace industry (2014 alloy), screws (2011 alloy), and industries with higher operating temperatures (2017 alloy).
Series 3: Characteristics: Aluminum alloys with manganese as the main alloying element, cannot be strengthened by heat treatment, have good corrosion resistance and good weldability. Good plasticity (close to super aluminum alloys). Disadvantages: Low strength, but strength can be increased through cold working. Coarse grains are easily produced during annealing. Applications: Oil guide seamless pipes used in airplanes (3003 alloy), beverage cans (3004 alloy).
Series 4: Mainly silicon, not commonly used. Some series 4 alloys can be strengthened by heat treatment, but some cannot.
Series 5: Characteristics: Mainly magnesium. Good corrosion resistance, good weldability, good fatigue strength, cannot be strengthened by heat treatment, strength can only be improved by cold working. Applications: Handles of lawn mowers, aircraft fuel pipes, bulletproof vests.
Generally, mid-range and above shoe racks are basically 6-series or 7-series.
Series6: Features: Mainly composed of magnesium and silicon. Mg2Si is the main strengthening phase, currently the most widely used alloy. The most used are 6063 and 6061; others include 6082, 6160, 6125, 6262, 6060, 6005, 6463. 6063, 6060, and 6463 have relatively low strength among the 6-series. 6262, 6005, 6082, and 6061 have relatively high strength among the 6-series. The mid-range frame of Whirlwind II is 6061. Features: Medium strength, good corrosion resistance, good weldability, good processability (easy to extrude and shape), good anodizing performance. Application range: Mechanical tools.
Series 7: Features: Primarily zinc-based, but sometimes small amounts of magnesium and copper are also added. Among them, ultra-hard aluminum alloys contain zinc, lead, magnesium, and copper, and their hardness is close to that of steel. The extrusion speed is slower than that of series 6 alloys, and welding performance is good. 7005 and 7075 are the highest grades in series 7 and can be strengthened through heat treatment. Applications: Aviation (aircraft load-bearing components, landing gear), rockets, propellers, spacecraft.
