Aluminum grades: types, properties and applications

Today, aluminum is used in almost all industries, from the production of food utensils to the creation of fuselages of spacecraft. For certain manufacturing processes, only certain aluminum grades that have certain physicochemical properties are suitable. The main properties of the metal are high thermal conductivity, ductility and ductility, resistance to corrosion, low weight and low ohmic resistance. They are directly dependent on the percentage of impurities contained in its composition, as well as on the technology of production or enrichment. In accordance with this, the main grades of aluminum are isolated.

Types of aluminum

All metal grades are described and introduced into a single system of recognized national and international standards: European EN, American ASTM and international ISO. In our country, aluminum grades are specified in GOST 11069 and 4784. In all documents, aluminum and its alloys are considered separately. In this case, the metal itself is divided into brands, and alloys do not have specifically defined signs.

In accordance with national and international standards, two types of microstructure of unalloyed aluminum should be distinguished:

• High purity with a percentage of more than 99.95%;
• Technical purity, containing about 1% of impurities and additives.

Iron and silicon compounds are most often considered as impurities. In the international ISO standard for aluminum and its alloys, a separate series has been singled out.

Aluminum grades

The technical form of the material is divided into certain brands, which are fixed to the corresponding standards, for example AD0 according to GOST 4784-97. In this case, the classification includes a high-frequency metal, so as not to create confusion. This specification contains the following brands:

1. Primary (A5, A95, A7E).
2. Technical (AD1, AD000, ADS).
3. Deformable (AM2, D1).
4. Foundry (VAL10M, AK12pch).
5. For deoxidation of steel (AB86, АВ97Ф).

In addition, there are also categories of ligatures - aluminum compounds, which are used to create alloys from gold, silver, platinum and other precious metals.

Primary aluminum

Primary aluminum (grade A5) is a typical example of this group. It is obtained by enriching the alumina. In nature, the metal in pure form does not occur because of its high chemical activity. Combining with other elements, it forms bauxites, nephelines and alunites. Subsequently, alumina is obtained from these ores, and pure aluminum is used as a result of complex chemical-physical processes.

GOST 11069 specifies requirements for primary aluminum grades, which should be noted by applying vertical and horizontal stripes with indelible paint of different colors. This material has found wide application in the advanced industries, mainly where raw materials require high technical characteristics.

Technical Aluminum

Technical aluminum is a material with a percentage of foreign impurities less than 1%. Very often it is also called undoped. Technical grades of aluminum in accordance with GOST 4784-97 are characterized by very low strength, but high corrosion resistance. Due to the absence of alloying particles on the surface of the metal, a protective oxide film is rapidly formed, which is stable. The grades of technical aluminum are distinguished by good thermal and electrical conductivity. In their molecular lattice there are practically no impurities that scatter the flow of electrons. Due to these properties, the material is actively used in instrument making, in the production of heating and heat-exchange equipment, lighting objects.

Deformable aluminum

The material to be deformed is a material that is subjected to hot and cold pressure treatment: rolling, pressing, drawing and other types. As a result of plastic deformations, semi-finished products of different longitudinal cross-sections are obtained from it: aluminum rod, sheet, tape, plate, profiles and others. The main grades of the deformable material used in domestic production are given in the normative documents: GOST 4784, OCT1 92014-90, OCT1 90048 and OCT1 90026. A characteristic feature of the deformable raw material is the solid structure of the solution with a high content of eutectic liquid phase, which is in equilibrium with Two or more solid states of matter.

The area of application of deformable aluminum, as well as that where an aluminum rod is used, is quite extensive. It is used both in areas requiring high technical characteristics from materials - in shipbuilding and aircraft construction, and at construction sites as an alloy for welding.

Foundry aluminum

Foundry aluminum grades are used for the production of shaped products. Their main feature is a combination of high specific strength and low density, which makes it possible to cast products of complex shapes without cracking.

According to their purpose, foundry brands are conventionally divided into groups:

1. Highly sealed materials (AL2, AL9, AL4M).
2. Materials with high strength and heat resistance (AL 19, AL5, AL33).
3. Substances with high corrosion resistance.

Very often, the performance characteristics of cast aluminum products are enhanced by various types of heat treatment.

Aluminum for deoxidation

The quality of the products produced is influenced by the physical properties of aluminum. And the use of low-grade grades of material is not limited to the creation of semi-finished products. Very often it is used to deoxidize steel - removing oxygen from the molten iron, which is dissolved in it and thus increases the mechanical properties of the metal. For carrying out this process, the brands AB86 and АВ97Ф are most often used.