Series 1 contains more than 99.00% aluminum, which has good electrical conductivity, good corrosion resistance, good weldability and low strength, and cannot be strengthened by heat treatment. Application scope: high-purity aluminum (containing more than 99.9% aluminum) is mainly used in scientific experiments, chemical industry and special purposes.

Series 2 is an aluminum alloy with copper as the main alloying element. Manganese, magnesium, lead and secret are also added for machinability. For example: 2011 alloy, attention should be paid to safety protection (harmful gas will be generated) during melting and tempering. 2014 alloy is used in aerospace industry with high strength. The strength of 2017 alloy is lower than that of 2014 alloy, but it is easier to process. 2014 can be strengthened by heat treatment. Disadvantages: serious tendency of intergranular corrosion. Application scope: aviation industry (2014 alloy), screws (2011 alloy) and industries with high service temperature (2017 alloy).

3 series aluminum alloy with manganese as the main alloying element can not be strengthened by heat treatment, and has good corrosion resistance and weldability. Good plasticity. (close to super aluminum alloy). Disadvantages: the strength is low, but it can be strengthened by cold working and hardening. It is easy to produce coarse grains during annealing. Scope of application: seamless oil guide tubes (3003 alloy) and cans (3004 alloy) used in aircraft. 4 series: mainly silicon, not commonly used. Part 4 can be strengthened by heat treatment, but some 4-series alloys can not be heat treated.

4 series is mainly silicon, which is not commonly used. Part 4 can be strengthened by heat treatment, but some 4-series alloys can not be heat treated.

5 series characteristics: mainly magnesium. Good corrosion resistance, good welding performance and good fatigue strength, which can not be strengthened by heat treatment, but can only be improved by cold working. Application: handle of lawn mower, conduit of aircraft fuel tank, bulletproof vest.

6 series is mainly magnesium and silicon. Mg2Si is the main strengthening phase and the most widely used alloy at present. 6063 and 6061 are used most, and others are 6082, 6160, 6125, 6262, 6060, 6005 and 6463. 6063, 6060 and 6463 have relatively low strength in the 6 series. 6262, 6005, 6082 and 6061 have higher strength in the 6 series. Characteristics: medium strength, good corrosion resistance, good welding performance, good process performance (easy extrusion) and good oxidation coloring performance. Application: Energy-transfer tools (such as car luggage rack, door, window, car body, heat sink, compartment shell).

7 series is mainly zinc, but sometimes a small amount of magnesium and copper are added. Among them, superhard aluminum alloy contains zinc, lead, magnesium and copper alloy which is close to the hardness of steel. The extrusion speed is slower than that of 6 series alloy, and the welding performance is good. 7005 and 7075 are the highest grades in 7 series and can be strengthened by heat treatment. Application: aviation (load-bearing components of aircraft, landing gear), rockets, propellers and spacecraft.