Eurocodes 9 – The European standard EN 1999
The European standard EN 1999-1-1, which is part of a series of standards EUROCODE 9 or Eurocodes 9, defines the general rules and regulations of the use of aluminum alloys in structures. Eurocodes 9 is an, in turn, part of a series of European standards for building under the general name Eurocode (EUROCODE).
The European standard EN 1999-1-1 in the countries of the former USSR has the following status:
- in Russia - a national annex is being prepared;
- Ukraine - adopted Standard DSTU-N B EN 1999-1-1:2010
- Belarus - accepted technical codes of practice TKP EN 1999-1-1-2009.
Aluminum alloys in Eurocode 9
Eurocodes 9 includes recommendations for use in construction:
- wrought heat-hardened aluminum alloys;
- thermally deformable aluminum alloys neuprochnyaemyh;
- casting aluminum alloys, as a thermally hardenable, and thermally hardened.
Below are the recommendations of the Eurocode 9 Usage deformable aluminum alloys, which are strengthened by thermal treatment.
Thermally deformable alloys
Eurocodes 9 It recommends the use in building constructions deformable thermally hardenable aluminum alloys of two series - 6xxx and 7xxx.
Of aluminum alloys of the 6xxx series, the following alloys are recommended for use in construction (we omit hereinafter, when designating the bulky "prefix" EN AW): 6082. 6061, 6005A, 6106, 6063 and 6060.
Aluminum alloys 7xxx series in building constructions applied only fusion, 7020.
Chemical composition of the aluminum alloys
table 1 shows the chemical composition of wrought aluminum alloys 6082. 6061, 6005A, 6106, 6063, 6060 and 7020.
Mechanical properties of profiles, sheets and strips
The tables 2 and 3 shows some typical mechanical properties of aluminum alloy products 6082. 6061, 6005A, 6106, 6063, 6060 and 7020. Details, see. the full text of EN 1999-1-1:2007.
Aluminum alloys 6082 and 6061
alloys 6082 and 6061 are analogs of the domestic alloy AD35 and AD33 GOST 4784-97 respectively.
Aluminum alloy products 6082 and 6061
Aluminium alloy 6082 the most widely used in construction industry as heat-hardenable alloy. Usually, this alloy is the main building for the aluminum alloy as the weldments, and constructions without welding. Alloy 6082 - a high-strength alloy, which is used in various types of rolled aluminum:
- solid and hollow extruded profiles;
- plates (thick sheets);
Alloy 6082 also increasingly used in constructions, who work in the marine atmosphere.
Alloy 6061 It is also commonly used heat-hardenable aluminum alloy for both structures using welding, so without. This alloy is used in the form of:
- solid and hollow profiles, and
Both alloys - 6082 and 6061 - usually used in a fully heat-strengthened state T6: 6082-T6 and 6061-T6.
alloy properties 6082 and 6061
Selection of alloys 6082 and 6061 as structural materials, it provides a favorable combination of their properties:
- high strength after heat hardening;
- good corrosion resistance;
- good weldability, whether by MIG, and by the TIG method;
- good formability (e.g., bending) in the T4 state (natural aging);
- good machinability.
The use of alloys 6082 and 6061 in extruded profiles is limited to less complex cross-sectional shapes, than for other 6xxx series alloys.
Aluminium alloy 6082 can be joined by rivets made of alloys 6082, 5754 or 5019 in the annealed condition O or a solid state.
welding alloys 6082 and 6061
For these alloys, it is necessary to take into account the loss of strength in the heat-affected zone of welding of welded joints (see. tables 2 and 3). The level of strength of welded joints can be restored to a certain extent due to the natural aging of the material in the heat affected zone of the weld. Loss of strength for the T6 condition is usually about 40 % (cm. tables 2.
Aluminum Alloy 6005A
Direct domestic analogue alloy 6005A absent.
Aluminum production from alloy 6005A
alloy 6005A, which is also suitable for building structures, It is used only in the form of extruded sections.
properties of the alloy 6005A
This alloy has a relatively high strength and, in the same time, It can be compressed into a more complex profiles, than alloys 6082 and 6061. This applies particularly to thin-walled hollow profiles.
The corrosion resistance of welded and non-welded structural members of similar resistance alloy 6005A alloy 6082. The other properties of the alloy similar to alloy properties 6005A 6082.
Alloy Welding 6005A
Similarly alloys 6082 and 6061 alloy 6005A lends itself well to TIG and MIG welding and has a similar loss of strength in the heat-affected zone of the weld: for T6 condition - about 40 % (cm. tables 2 and 3).
Aluminum alloys 6060, 6063 and 6106
alloys 6060 and 6063 are analogues of domestic AD31 alloy according to GOST 4784. Alloy 6063 almost identical in chemical composition to the alloy AD31, alloy 6060 It refers to a portion AD31 alloy containing magnesium to 0,6 %. Analogue alloy 6106 in GOST 4784-97 is absent.
The use of alloys 6060, 6063 and 6106
alloys 6060, 6063 and 6106 recommended for building constructions. These alloys are used only in the form of cold-pressed and articles. they are used, if the strength is not of paramount importance, but it takes a good product appearance. These alloys provide good resistance to environmental effects, well to application of protective and decorative coatings and, the most important thing, They have the ability to be pressed into profiles with thin walls and complex cross-section.
These alloys are especially suitable for the anodization processes, and similar surface finish.
welding alloys 6060, 6063 and 6106
Like all alloys 6xxx series alloys 6060, 6063 and 6106 well as a welded with MIG, and a method of TIG and also lose strength in the heat affected zone of welded joints. Loss of strength for the T6 condition is about 40 % (cm. tables 2 and 3).
Aluminium alloy 7020
Alloy 7020 It recommended for use in welded and non-welded construction structures.
Aluminum alloy products 7020
From this high-strength alloy produce solid and hollow extruded sections, thick and thin sheets, and pipe. Of the alloy is not easy to extrude complex profiles, as the 6xxx series alloys. Therefore, the product of an alloy 7020 usually only made to order, and they may have a longer delivery time.
Alloy 7020, usually, used in a fully thermally hardened state - 7020-T6. This alloy has a high strength in the heat affected zone of the weld, than the 6xxx series alloys, thanks to its high strength properties after natural aging.
alloy properties 7020
this alloy, as well as other 7xxx series alloys, It is highly sensitive to climatic influences. Therefore, its normal operation depends on the correct processing and manufacturing methods, and control of the chemical composition. Due to the exposure of the subsurface corrosion in the step of manufacturing the alloy product is used only in the state T4, and only after complete manufacture of the entire structure, possibly, subjected to artificial aging.
If the welding heat-affected zone is not subjected to heat treatment after welding, it may be necessary to protect it from the impact of climatic factors.
If the product of the alloy 7020 T6 state is subjected to any processing steps, which can cause hardening, for example, such as, flexible, cutting or punching, It increases the danger of cracking due to stress corrosion. It is very important and therefore should be direct collaboration of designers and manufacturers for the intended application and the possible operating conditions of the alloy product 7020.
alloy welding 7020
Alloy 7020 It lends itself well to TIG welding and MIG. Loss of strength in the HAZ to T6 state is approximately 20 % (cm. tables 2 and 3).
Source: European standard EN 1999-1-1:2014