Aluminum and alloys

Aluminum It is used to manufacture various parts and alloys based on it. During the study and application of this metal, a technology for its processing was developed. Alloying is used to impart the required properties to the material. This process involves the molten state, aluminum mixed with melts of additional elements.

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This process improves the quality of metallurgical products. Depending on the chosen proportions and complementary elements, the chemical, mechanical, and physical properties of the metal change. Today, pure aluminum It is practically not used in industry due to its low strength. Alloys, however, have found widespread use, and their proportions and processing technologies are constantly being improved. Welding aluminum It is performed using a spot or argon arc machine; electric arc welding is also used.

Basic properties of aluminum

The main factors determining the wide range of use of any material are its properties and performance indicators. Aluminum-based alloys are used in almost all areas of activity. The simple reason for such prevalence is Basic properties of aluminum, which are listed.

• density - 2.7 g/cm³
• the melting point of technical aluminum is 658 °C;
• the melting point of pure aluminum is 660 °C;
• specific heat of fusion— 390 kJ/kg;
• boiling point - 2500 °C;
• specific heat of evaporation— 10.53 MJ/kg;
• specific heat capacity— 880 J/kg·K;
• the tensile strength of cast aluminum is 10-12 kg/mm², the tensile strength of deformed aluminum is 18-25 kg/mm², the tensile strength of alloys is 38-42 kg/mm²;
• Brinell hardness: 24...32 kgf/mm²;
• plasticity of technical grade - 35 %;
• plasticity of pure - 50 %;
• Young's modulus—70 GPa;
• Aluminum has high electrical conductivity (37 10⁶ Cm/m) and thermal conductivity (203.5 W/(m K)), 65 % from the electrical conductivity of copper, has high light reflectivity;
• Weak paramagnetic;
• Thermal coefficient of linear expansion 24.58·10^-6TO^-1 (20…200 °C);
• Specific resistance 0.0262..0.0295 Ohm mm²/m;
• Temperature coefficient of electrical resistance 4.3 x 10^-3K^-1Aluminum enters the superconducting state at a temperature of 1.2 Kelvin.

An important property that distinguishes aluminum-based alloys — high ductility. It can be easily rolled into foil, which is especially important for use in electronics and electrical engineering. The material can be easily processed with low mechanical forces. Its low melting point allows for remelting and fabrication of aluminum alloy parts with minimal energy consumption, reducing production costs and the cost of the product itself.

Aluminum grades according to GOST

Aluminum and its alloys, like other metals, are labeled according to established standards. Thus, there are aluminum grades according to GOST, which are given in the lists.

Wrought aluminum alloys:

Heat-treated hardening:

• Duralumin D1, D16, D20*, aluminum-copper-manganese alloys [Al-Cu-Mg];
• Alloy avial (AV);
• High-strength alloy (B95);
• Alloys for forging and stamping (AK6, AK8, AK4-1 [heat-resistant]).

Not hardenable by heat treatment:

• Aluminum-manganese alloys (AMts);
• Aluminum alloys with magnesium (AMg2, AMg3, AMg5, AMg6).

Casting aluminum alloys for shaped casting:

• Aluminum-silicon alloys (silumin /) Al-Si (AL2, AL4, AL9) - high density of castings, easy to cut, characterized by high linear performance;
• Aluminum-copper alloys Al-Cu (AL7, AL19) - high mechanical properties after heat treatment, easy to machine;
• Aluminum-magnesium alloys Al-Mg (AL8, AL27) - increased corrosion resistance, improved mechanical properties, easy to machine;
• Heat-resistant aluminum alloys (AL1, AL21, AL33) - easy to cut, increased heat resistance.

Classification in terms of ease of mechanical processing (Soft and ductile, difficult to machine):

• Annealed - D16, AB;
• Not hardened by heat treatment - AMts, AMg2, AMg3, AMg5, AMg6.

Relatively strong and hard aluminum alloys that are fairly easy to machine:

• Hardened and artificially aged: D16T, D16N, AVT;
• Forging: AK6, AK8, AK4-1;
• Foundry: AL2, AL4, AL9, AL8, AL27, AL1, AL21, AL33.