Updated Wrought alloys 

Aluminium alloy 6063

Chemical composition

Nominal chemical composition

Al-0,7Mg-0,4Si

Chemical composition according to EN 573-3

Table 1 – The chemical composition of the alloy 6063, its modifications 6063A and 6463, as well as its analogue, alloy 6060 (EN 573-3)

Designations

  • EN 573-3: EN AW-6063
  • USA standard ANSI H35.1: 6063
  • Teal Sheet (Aluminum Association): 6063
  • Unified Numbering System (UNS): A96063
  • ISO 209: 6063 (to 2007 Year by ISO 209-1 – AlMg0,7Si)
  • Japan: A6063
  • DIN 1725-1 (canceled): none

Metallurgical characteristics

  • series – 6xxx
  • Wrought
  • Thermally hardenable
  • The main alloying elements – magnesium and silicon, without special additives.
  • hardening phase – intermetallic compound Mg2Si. At nominal chemical composition and complete dissolution of the alloying elements of this amount of the reinforcing compound is about 1 %, without excessive silicon content.
  • Any other elements considered as impurities.
  • The absence of corrective additives can create difficulties in controlling grain growth after heating for quenching and quenching [2].
  • Typical conditions: T5, T6 and T66.
  • The place of alloy 6063 among other 6xxx series alloys are shown . in the figure below.

Typical applications

pressed aluminum profiles:

  • Enclosing constructions, such as windows, facade constructions, enter the store, winter gardens.
  • tubes, rail, sport equipment.
  • irrigation pipes
  • Bodies of trucks and vans [1]

Standardized production

Table 2 – Standardized production [1]

The mechanical properties of the alloy 6063

Normalized mechanical properties

Table 3 – Mechanical properties of extruded rods/bars, tubes, profiles of aluminium allloy 6063 according to EN 755-2

Table 4 – Mechanical properties of extruded profiles and tubes of aluminium allloy 6063 according to EN 754-2

Typical mechanical properties

Table 5 – Typical mechanical properties of alloy 6063 [1]

Poisson's ratio

0,33.

Elastic modulus

Tensile modulus - 68300 MPa.
shear modulus - 25800 MPa.
compressive modulus - 69700 MPa.

Physical properties

Density

2,69 g / cm3 at 20 ° C

melting and crystallization temperature

Alloy liquidus temperature 6063: 655 ° C

the solidus temperature of the alloy 6063: 615 ° C

The coefficient of linear thermal expansion

Linear: 23,4 μm / (m ° C) in the range from 20 to 100 ° C.
Volume: 67∙10-6 m3/(m3 ∙ ° С)

Weldability

  • Good arc-welded under inert gas, in particular, argon arc welding, as non-consumable electrode (GTAW-TIG), and consumable electrode (GMWA-MIG).
  • Conventional welding alloy - 4043.

Groove weld strength

Weld strength is an important factor in selecting the right filler alloy. The heat of welding softens aluminum alloys, adjacent to the weld, if they are in any state, except annealed. In most groove welds, the base alloy HAZ will control the strength of the joint after welding (Fig.. 1)

For complete annealing of heat treatable alloys, including, alloy 6063, required from 2 to 3 hours at their annealing temperature combined with slow cooling. This does not happen when welding., and the HAZ will consist of several stages of dissolution and varying degrees of precipitation depending on thermal conditions, as shown in pic. 2. The degree of softening of the HAZ is very sensitive to the maximum temperature. reached in a certain place, as well as the time at this temperature [1].

 

Fig. 1 – Heat-Affected Zone in Welded Aluminium Joints [2]

Heat treatment

Alloy 6063 refers to 6XXX series alloys (Al-Mg-Si). These alloys, containing Mg and Si are easily heat treatable. is he 6063 has relatively low volume fractions of Mg and Si and therefore Mg2Si completely dissolves during solid solution treatment and then precipitates during aging.

Annealing temperature

415 ° C.

Quenching temperature

520 ° C.

Artificial aging

175 ° C. 8 hours.

bending

In the state T4.

Press quenching

The cooling rate after extrusion should be high enough, to keep Mg and Si in solid solution. In this case, the mechanical properties will be maximum due to the precipitation of Mg2Si particles during subsequent aging (Fig. 3).

Cooling rate for series alloys 6000 determined by the transverse dimension of the profile and the cooling medium, such as:

  • calm air
  • fans
  • water-air mixture
  • water.

Table 5 typical cooling rates shown, which are required for effective hardening of profiles from alloys of the series 6000, including, alloy 6063 [5].

 

Fig. 3 – Diagrammatic sketch of press heat treatment cycle for 6063 alloy [4]

Table 6 – Recommended Quench Rates and Methods for Various 6000 Series Alloys [5]

Modifications

Aluminum alloy 6063

  • 0,15-0,35 % Fe; 0,30-0,6 % And; 0,6-0,9 % Mg
  • Strength properties slightly higher, than an alloy 6063 (on 15-25 MPa for condition T6) without reducing the quality of anodizing

Aluminium alloy 6463

  • 0,15 % Fe; 0,20 % Cu
  • Strength properties below, than an alloy 6063
  • It is used to obtain a shiny surface anodized.

Alloy 6063 in Eurocode 9 (EN 1999-1-1)

Table 5 – Keys [3]

 

  • The material properties given in this section are specified as characteristic values. They are based on the minimum values given in the relevant product standard (Table 6) [3]
  • Characteristic values of the proof strength f0 and the ultimate tensile strength fu for aluminium alloy 6063 for a range of tempers and thicknesses are given in Table 7 for sheet, strip and plate products; Table 8 for extruded rod/bar, extruded tube and extruded profiles and drawn tube [3].

Table 7 – Fragment of table 3.1a from EN 1999-1-1.
Alloy 6063 among alloys from the series 6000 [3]

Table 8 – Excerpt from table 3.2.b from EN 1999-1-1.
Alloy 6063 [3]

Sources:

  1. Aluminum and Aluminum Alloys, ed. J. R. Davis – 1996
  2. TALAT Lecture 4204 – Design Aspects
  3. EN 1999-1-1:2007 Eurocode 9: Design of aluminium structures – Part 1-1 : General structural rules
  4. Carl V. Lynch, Aluminum Extrusion Technology Seminar, Chicago, 1969

In Handbook of Wrought Aluminum Alloys