Aluminum in construction (Eurocode 9)

 

Aluminum is not just a single unique material, a gives a family of different groups (series) aluminum alloys. The mechanical properties of aluminum alloys are widely vary from one group to the other, and within each group. This diversity of properties and characteristics of the aluminum alloys allows choosing construction material, which is optimal for a particular building or structure.

The principal aluminum alloys, which are recommended for use in the construction industry.

Wrought alloys

Below are deformable aluminum alloys, that the European standard EN 1999 (Eurocode 9) recommends for use in building structures in the form of:

• sheets (EN 485),
• tapes (EN 485),
• extruded pipes (EN 755),
• extruded profiles (EN 755),
• pressed rods (rods) (EN 755),
• cold drawn profiles (EN 754),
• forgings (EN 586).

8 series wrought alloys

All wrought aluminum alloys are grouped into eight series - eight groups. According to the classification of the American Aluminum Association, which is accepted all over the world, designation of wrought aluminum alloys consists of four digits. The first of four digits characterizes the main alloying element (sometimes two) of this group, the remaining three digits are complementary and help to distinguish the alloys within this group.

Eurocodes 9 Recommended for use in structures of aluminum alloys not all series, but only a series of 3000, 5000, 6000, 7000 и 8000 – several, from 1 to 6, alloys of each series.

Technical aluminum: series 1000

In this series, the aluminum content percentage is very high - from 98,80 to 99,00 %. Various impurities content technical aluminum variants called marks. Unlike alloys, brands do not have special alloying elements, and differ from each other only by the content of impurities.

Brand series of aluminum 1000 used in lightly loaded structures, mainly in the form of sheets. Electrical and chemical industries use aluminum brands in this series to cables and capacitors, them so they provide high corrosion resistance, which is typical for aluminum as a metal.

Yield strength grades of aluminum is very low - about 30 N / mm², however, they have a very high ductility - their elongation is from 30 to 40 %.

If technical aluminum subjected to cold plastic deformation - work hardening, its yield stress may reach 100 N / mm². However, Unfortunately, this occurs at the expense of ductility - elongation decreases with up to 3-4 %.

• In the list of aluminum alloys, that Eurocode 9 recommended for use in construction, Aluminum brand of series 1000 There are no.

Aluminum-copper alloys: series 2000

These aluminum alloys are produced mainly in the form of profiles, sheets and pipes. The thermally hardened state they reach the yield strength to 300 N / mm2, while maintaining sufficient ductility with elongation of about 10 %.

As corrosion resistance of these alloys is not too high, they need to be protected from corrosion, particularly when used in corrosive environments. Due to the poor weldability series alloys 2000 they are rarely used in the construction industry. Basically, these alloys are used in aircraft to compound them to each other by rivets.

• In the list of aluminum alloys Eurocode 9 series aluminum alloys 2000 not.

Aluminum-manganese alloys: series 3000

These alloys do not possess the ability to thermal hardening. They have a strength slightly higher, than pure aluminum and very high ductility. High ductility level allows to apply to these alloys very intense cold plastic deformation processes to improve their strength properties. They are corrosion-resistant. The most commonly used for the manufacture of panels and parts for roofing systems.

• The list of aluminum alloys, recommended Eurocodes 9 for use in construction, alloys made
  – 3004,
  – 3005 и
  – 3103.

Aluminum-silicon alloys: series 4000

The properties of these alloys similar to those of a series of alloys 3000. However, as structural alloys, they are rarely used. their main application - welding wire.

• In the list of aluminum alloys Eurocode 9 alloys of series 4000 There are no.

Aluminum-magnesium alloys: series 5000

Even though these alloys do not have the ability to receive a thermal hardening, their mechanical properties can reach values, are higher, than the series alloys 1000, 3000 и 4000. The strength of these alloys is increased by the work hardening - cold plastic deformation - to yield stress 200 N / mm2 while maintaining a relatively high ductility (elongation up to 10 %). The corrosion resistance of these alloys is very high, particularly in the marine environment, magnesium at a content not higher 6 %. These alloys are often used in welded constructions, because their strength is not so drastically reduced, as a thermally hardened alloys.

• Among aluminum alloys, recommended Eurocodes 9 for use in construction, six of a series of alloys 5000:
  – 5005,
  – 5049,
  – 5052,
  – 5083,
  – 5454 и
  – 5754.

Aluminum-magnesium-silicon alloys: series 6000

Using the heat treatment the strength of these alloys may be as high yield strength to 250 N / mm2 with a decent plasticity to 12 % elongation. These alloys are corrosion resistant. They are particularly well suited for extrusion and pipe profiles, but it is also used for rolling sheets. series alloys 6000 used in welded constructions, and in the construction of bolted and riveted.

• Series aluminum alloy 6000 Eurocodes 9 recommends six alloys for use in construction:
  – 6060,
  – 6061,
  – 6063,
  – 6005A,
  – 6082 и
  – 6106.

Aluminum-zinc alloys: series 7000

Of these alloys produce aluminum as the extrusion, and rolling method. They are divided into two subfamilies based on the copper content as a third alloying element.

alloys AlZnMg

These alloys attain high strength with a yield higher 250 N / mm2 with good ductility (elongation approx. 10 %). Moreover, These alloys are corrosion resistant. These alloys are typically used in constructions, so they are particularly suitable for welded structures, due to their ability to self-hardening, that allows to restore the initial strength in the welding heat-affected zone.

alloys AlZnMgCu

These alloys reach their maximum strength after hardening by thermal. They reach the yield strength 500 N / mm2. However, these alloys have a low weldability and low corrosion resistance due to the presence of copper. Therefore, these require a corrosion protection alloy as plating or painting.

• Only one of this series alloy included in the list of Eurocode alloys 9. This alloy without copper doping
  – 7020.

series 8000: Aluminum-iron-silicon alloys

Alloys of this series are mainly used for the production of foils for packaging, and electrical wires.

• In Eurocodes 9 there is only one alloy in this series - Alloy
  – 8011A.

Source: EN 1999-1-1: 2007 + A1: 2009