- 21 November 2024
Aluminum is a lightweight paramagnetic metal, silver-white in color, with a density of 2712 kg/m3. It is easy to form, cast and machine.
At first glance, the unique properties of aluminum attract attention. It is a metal with enhanced thermal and electrical conductivity and corrosion resistance. The melting point of technical aluminum is 658°C, and the purity is elevated to 660°C. The resistance of aluminum castings is 10-12 kg/mm², deformable 18-25 kg/mm², alloys 38-42 kg/mm². The ductility of technical aluminum is 35%, pure aluminum 50%.
There are different types of aluminum alloys. The most common are:
- Duralumin - named after the German city where industrial production of the alloy began. Aluminum alloy (base) with copper (Cu: 2.2-5.2%), magnesium (Mg: 0.2-2.7%) manganese (Mn: 0.2-1%). It is subject to quenching and aging, often plated. It is a structural material for aerospace and transportation engineering.
- Silumin - light casting alloys of aluminum (base) with silicon (Si: 4-13%), sometimes up to 23%, and some other elements: Cu, Mn, Mg, Zn, Ti, Be). These types of aluminum alloys are suitable for the production of parts with complex configurations, mainly in the automotive and aerospace industries.
- Magnal are alloys of aluminum (base) with magnesium (Mg: 1-13%) and other elements, which are characterized by high corrosion resistance, good weldability and high ductility.
The main advantages of all aluminum alloys are their low density (2.5-2.8 g/cm3), high strength (per unit weight), satisfactory resistance to atmospheric corrosion, low cost and ease of production and processing.
Aluminum has high electrical conductivity, thermal conductivity, corrosion and frost resistance, and ductility. It is well suited for stamping, forging, drawing and rolling. The metal can be welded well in a variety of ways. Other properties of aluminum include its low density of about 2.7 g/cm3. The melting point of this metal is about 660°C. The mechanical, physicochemical and technological properties of aluminum depend on the presence and amount of impurities that deteriorate the properties of the pure metal. The main natural impurities are silicon, iron, zinc, titanium and copper.
Based on the degree of purification, aluminum is distinguished between high purity and technical purity. The practical difference lies in the difference in corrosion resistance in certain environments. The purer the metal, the more expensive it is. Technical aluminum is used for the production of alloys, rolled products and cable and wire products. High-purity metal is used for special purposes.
In terms of electrical conductivity, aluminum is second only to gold, silver and copper. And its combination of low density and high electrical conductivity allows it to compete with copper in the field of cable and wire products. Long-term annealing improves electrical conductivity, while cold hardening degrades it.
The thermal conductivity of aluminum increases as the purity of the metal increases. Manganese, magnesium and copper impurities reduce this property. These values are much higher than for most metals. The higher the purity of aluminum, the better it is able to reflect light from the surface. Aluminum in contact with oxygen forms a thin, durable aluminum oxide film. This coating protects the metal from subsequent oxidation and provides good anti-corrosion properties. Aluminum alloys are resistant to atmospheric corrosion, seawater and fresh water and virtually do not interact with organic acids, concentrated or dilute nitric acid.
All types of aluminum are widely used as a structural profile in the manufacture of cookware, foil in the food industry. Aluminum alloys are also used in the aerospace industry. The disadvantage of aluminum as a structural material is its low strength, so in order to strengthen aluminum, alloys with copper and magnesium are added to produce duralumin.
Various types of aluminum are used in electrical engineering for wires, shielding and even in microelectronics for depositing conductors on the surface of microchip crystals. Due to their complex properties, aluminum tubes are widely used in heating equipment. Profile tubes are used in construction and industrial assembly of structures and in furniture manufacturing. Aluminum alloys are used in cryogenic technology. The increased reflectivity combined with the low cost and ease of vacuum deposition makes aluminum an optimal material for the production of mirrors.
Aluminum is also used in the production of facade, anti-slip and decorative coatings. In the automotive industry for the production of thresholds and steps. Rolled sheets are used in construction, fuel, food and chemical industries, as well as in building and mechanical engineering. Plates, due to their functional properties, are used in the construction industry most often as an insulating or finishing material.
