Overview of Aluminum Alloy

Aluminum alloy is a kind of nonferrous metal structure material which is widely used in industry. It has been widely used in aviation, aerospace, automobile, machinery manufacturing, shipbuilding and chemical industry. With the rapid development of science and technology and industrial economy in recent years, the demand for aluminum alloy welded structural parts is increasing day by day, which makes the research on the weldability of aluminum alloy also in-depth. The wide application of aluminum alloy promotes the development of aluminum alloy welding technology, and at the same time, the development of welding technology has expanded the application field of aluminum alloy, so the welding technology of aluminum alloy is becoming one of the research hotspots.

The density of pure aluminum is small (ρ=2.7g/m3), about 1/3 of iron, low melting point (660℃), aluminum is a face-centered cubic structure, so it has a very high plasticity (δ:32~40%, ψ:70~90%), easy to process, can be made into a variety of profiles, plate. Good corrosion resistance; However, the strength of pure aluminum is very low, and the annealing state σb value is about 8kgf/mM2, so it is not suitable for structural materials. Through long-term production practice and scientific experiments, people gradually to add alloying elements and the use of heat treatment and other methods to strengthen aluminum, which obtained a series of aluminum alloys. The alloy formed by adding certain elements can maintain the advantages of pure aluminum light, but also have high strength, the σb value of 24 ~ 60kgf/mm2 respectively. This makes its "specific strength" (strength and specific gravity of the ratio of σb/ρ) is better than many alloy steel, become an ideal structural material, widely used in machinery manufacturing, transportation machinery, power machinery and aviation industry and other aspects, the aircraft fuselage, skin, compressor often to aluminum alloy manufacturing, in order to reduce the weight. By using aluminum alloy instead of steel plate, the weight of the structure can be reduced by more than 50%.

Aluminum alloy density is low, but the strength is relatively high, close to or more than high quality steel, good plasticity, can be processed into a variety of profiles, with excellent electrical conductivity, thermal conductivity and corrosion resistance, widely used in industry, the amount of only second to steel.

Aluminum alloy is divided into two categories: cast aluminum alloy, used in the as-cast state; Deformed aluminum alloy, able to work under pressure. Can be processed into various forms, specifications of aluminum alloy material. Mainly used for manufacturing aviation equipment, building doors and Windows, etc.

Aluminum alloy can be divided into deformation aluminum alloy and casting aluminum alloy by processing methods. Deformed aluminum alloy is divided into non - heat treatment and heat treatment of reinforced aluminum alloy. Non heat treatment type can not be strengthened through heat treatment to improve the mechanical properties, can only be strengthened through cold processing deformation, it mainly includes high pure aluminum, industrial high pure aluminum, industrial pure aluminum and antirust aluminum, etc.. Heat treatable reinforced aluminum alloy can be used by quenching and aging and other heat treatment means to improve the mechanical properties, it can be divided into hard aluminum, forged aluminum, super hard aluminum and special aluminum alloy, etc..

Some aluminum alloys can be heat treated to obtain good mechanical, physical and corrosion resistance.

Casting aluminum alloy by chemical composition can be divided into aluminum silicon alloy, copper alloy aluminum, aluminum and magnesium alloys, aluminum zinc alloy and aluminum rare earth alloy, the aluminum silicon alloy and a simple aluminum silicon alloy (not strengthening heat treatment, mechanical performance is low, the casting performance is good), special aluminum silicon alloy, heat treatment reinforcement, high mechanical properties, good casting properties),