6061 Aluminium Alloy
Aluminium alloy 6061 is a medium- to high-strength, heat-treatable wrought aluminium alloy. It offers excellent corrosion resistance and very good weldability, although its strength decreases in the weld area. The alloy provides moderate fatigue strength. In the T4 temper, it demonstrates good cold-working performance, but its formability becomes limited in the T6 temper. It is also not recommended for very complex profiles.
GNEE supplies aluminium alloy 6061 in various tempers and product forms to meet different engineering and manufacturing requirements.
Chemical Composition of Aluminium Alloy 6061
Nominal Composition [1]
Al-1.0Mg-0.6Si-0.30Cu-0.20Cr
Chemical Composition According to EN 573-3
In the current European standard EN 573-3:2019, only one alloy designation exists: EN AW-6061A. The alloy 6061 without the "A" designation is no longer included (see Table 1).
In earlier versions of the EN 573-3 standard, two alloys were listed: 6061 and its modified version 6061A (Table 2).
The notes "e" and "15" specify that the lead (Pb) content in alloy 6061A must not exceed 0.003%.
In the EN 755-2 standard, which defines mechanical properties, only the alloy 6061 is referenced-without the "A" suffix.
Chemical composition of 6061 aluminium alloy according to EN 573-3:2019
Chemical composition of 6061 aluminium alloy according to EN 573-3:2001
Designations
EN 573-3: EN AW-6061A and EN AW-Al Mg0.7Si(A)
International Registration for Teal Sheats - Aluminum Association: 6061
Unified Numbering System (UNS): A96061, ISO 209:2007: 6061
Metallurgical properties of aluminum alloy 6061.
Wrought
Thermally hardenable.
Alloys of medium to high strength can be strengthened through thermal hardening (ageing).
achieves strength higher than alloy 6005A.
Good corrosion resistance.
It welds well, however the weld area's strength is diminished.
Has a medium fatigue strength.
It can be cold formed satisfactorily in the T4 condition, but its formability is limited in the T6 condition.
Not appropriate for extruded profiles with complicated cross-sections.
The position of alloy 6061 in comparison to other alloys in the 6xxx series is shown in the figure below.
Typical application of aluminium alloy 6061
Bicycle frames
Trucks
Passenger carriages
Sports equipment
Structural pipes
Structural parts that require increased strength, good weldability and high corrosion resistance
Frame parts, seat rails, passenger car bumpers
Truck frames
Shipbuilding
Bridges and mobile military bridges
Aerospace products
Pylons and Towers
Transport
Boiler making
Motorboats
Rivets
Physical Properties
Elastic Modulus
In tension: 68,900 MPa
In compression: 69,700 MPa
Density
2.70 g/cm³ at 20 °C
Thermal Properties
Melting temperature range: 575–650 °C
Linear coefficient of thermal expansion: 23.6 µm/(m·°C) within the 20–100 °C temperature range
Weldability
Welding Methods
Aluminium alloy 6061 demonstrates excellent weldability using inert gas arc welding, particularly argon-arc processes such as:
GTAW (TIG) with a non-consumable electrode
GMAW (MIG) with a consumable electrode
A commonly used filler alloy is 4043.
Welded Joint Strength
Weld strength plays a critical role when choosing the most suitable filler material. During welding, the heat input softens the regions adjacent to the weld in any temper other than the fully annealed state. In most groove weld configurations, the strength of the welded joint is determined by the heat-affected zone (HAZ) of the base metal (Fig. 1).
For heat-treatable alloys like 6061, full annealing typically requires 2–3 hours at the annealing temperature followed by slow cooling. Since these conditions are not achieved in welding, the HAZ undergoes partial dissolution and various levels of precipitation depending on thermal exposure, as illustrated in Fig. 2. The degree of softening within the HAZ is highly dependent on the peak temperature attained at each point and the duration of exposure at that temperature.
GNEE provides high-quality 6061 aluminium materials suitable for welding applications where mechanical performance and joint reliability are critical.
