44956_04

8/12/2019 44956_04

http://slidepdf.com/reader/full/4495604 1/10

Chapter A.4

The Most Common Wrought Aluminium Alloys4.1. The 1000 Series 61

4.2. The 3000 Series 61

4.3. The 5000 Series 62

4.4. The 8000 Series 65

4.5. The 2000 Series 65

4.5.1. The Quenched and Naturally Aged Tempers T4 and T451 65

4.5.2. The Artificially Aged Tempers T6 (T651) and T8 (T851) 664.6. The 6000 Series 67

4.7. The 7000 Series 68

4.7.1. 7000 Alloys Without Added Copper 68

4.7.2. 7000 Alloys with Added Copper 69

References 69

59

8/12/2019 44956_04


Chapter A.4

The Most Common Wrought Aluminium Alloys

This chapter gives a brief description of the most widely used aluminium alloys. No

indications on very specific alloys will be given, especially on those used for the

construction of aircraft or heat exchangers in cars, for example. Specialist books [1] or

technical documents from suppliers [2] should be consulted for these alloys.

4.1. THE 1000 SERIES

This series includes two categories of grades: the refined alloys and the others such as

1050A and 1200.

The refined alloys (1199, 1198) have a degree of purity between 99.90 and 99.999%.

Depending on their purity, they are used in the manufacture of electrolytic condensers (so-

called etched metal), lighting devices (bright-trim quality), and for decorative applications

in the building sector and luxury packaging (cosmetics, perfumes). The metal is usuallyanodised.

The 1050A alloy is more than 99.50% pure and is one of the most widely used grades. It

is a good compromise between mechanical resistance, capacity for plastic deformation and

decorative appearance. It has a wide range of applications: packaging, buildings, sheet

metal working, fins and tubes for heat exchangers, electrical conductors, etc.

The 1200 alloy is between 99 and 99.5% pure, and replaces 1050A whenever its plastic

formability is adequate (packaging, circles for kitchen utensils).


Industrial alloys of the 3000 series (Figure A.4.1) contain between 1 and 1.5% manganese.

This alloying element significantly enhances the mechanical properties of aluminium and

adds between 40 and 50 MPa to the minimum guaranteed tensile strength values, while

retaining good formability.

The 3003 alloy is the most representative alloy in this series. Adding up to 0.20%

copper provides a further increase in mechanical resistance, and adding up to 0.7% copper

makes it possible to obtain a fine-grained structure.

As with all the alloys in this series, it has the highest capacity plastic deformation in the

annealed temper O.

61

8/12/2019 44956_04


The main applications of 3003 are in the building sector (cladding panels, roofing

sheet), fabrication, sheet metal work, heat exchanger tubing, circles for kitchen utensils,

etc.

3103 is a variant of 3003, with no copper added.

The 3004 alloy, with roughly 1% magnesium added, offers slightly better mechanicalproperties, while retaining the overall properties of 3003. It is chiefly used for cans (food

cans), circles for kitchen utensils, buildings (coil-coated sheets), etc.

Alloys 3005 and 3105 are two alloys whose mechanical properties and formability fall

between those of 3003 and 3004. They are used in the fields of building, fabrication, sheet

metal work, thermal insulation, capsuling, etc.


The mechanical properties of the alloys in this series increase with increasing magnesium

content (Figure A.4.2). Industrial wrought alloys rarely contain more than 5% magnesium,

because above this level, the stability of the alloy decreases, particularly under the

influence of temperature.

Prolonged holding at a high temperature leads to the precipitation of the intermetallic

compound Al3Mg2 at the grain boundaries. The possible effects of this are described in

Section B.6.4. If required by the application, a stabilisation heat treatment can be carried

out on alloys containing 3% magnesium or more (H321 and H116 tempers).

Most alloys of the 5000 series contain other additions such as manganese, chromium

and titanium, which provide a further increase in tensile strength and/or certain properties

such as corrosion resistance, weldability, and others.

Figure A.4.1. Mechanical properties of 3000 series alloys.

Corrosion of Aluminium62

8/12/2019 44956_04


These alloys

– are very suitable for welding, except those alloys containing between 1.8 and 2.2%

magnesium. The tensile strength of a welded joint is approximately equal to that

measured on the parent plate in the annealed temper;

– have good properties at low temperatures; and

– have good corrosion resistance, whether welded or not.

Surface treatments such as brightening or anodising can give them a very attractive

surface appearance, especially when the alloy is derived from base metal that is low in iron

and silicon; this is the case of alloy 5657 (base metal 1080).

The most common alloys of the 5000 series are listed below (Figure A.4.3):

Alloy 5005 contains about 0.6% Mg and replaces 1050A or 1200 whenever a slight

improvement in mechanical properties is required. Anodised (OAB quality, anodic

oxidation quality for building) or coil-coated 5005 is very widely used for building

applications (external cladding panels, etc.).

Alloy 5657 is a variant of 5005 using a purer base metal (1085). This means the so-

called bright-trim quality for cosmetics packaging, lighting and decorative purposes can be

obtained.

Figure A.4.2. Effect of magnesium content of mechanical properties of the 5000 series alloys in the annealed

(W) temper.

The Most Common Wrought Aluminium Alloys 63

8/12/2019 44956_04


Alloy 5052, with 2.5% magnesium and added chromium, is a good compromise

between mechanical resistance, formability, fatigue resistance and corrosion resistance. Itis widely used in the H28 temper for food cans and in a large number of applications in

fabricating, commercial vehicle bodies, road signs, etc.

Alloy 5049 is a variant of 5052 containing manganese but no chromium. Coil in 5049 is

widely used for thermal insulation and for sheet metal forming.

Alloys 5454, 5754 and 5154A, combining a magnesium level between 2.5 and 4% with

minor additions of manganese or chromium, are widely used in the building sector, civil

engineering, transport and mechanical industries. Wire in 5154A is frequently used as rivet

stock, and in thinner gauges for mosquito screens.Alloys 5086 and 5083, containing between 3.5 and 5% magnesium with added

manganese and chromium, offer the highest mechanical properties of all semi-products of

the 5000 series, including those at cryogenic temperatures. They are suitable for welding

and have outstanding corrosion resistance, especially in maritime environments. They

have enjoyed growing popularity in naval construction and industrial fabrication.

Alloy 5182, with 4–5% magnesium but with less iron and silicon, provides a good

compromise between mechanical resistance and formability in the annealed temper. It is

used for reinforcements in cars. Lacquered 5182 in H28 temper retains a good level of

mechanical resistance and residual formability, which means it can be used for the

manufacture of can ends for beverage cans.

Alloy 5019, with 5% magnesium, is devoted to specific products such as rivet wire, zip

fasteners, clips and staples for use in contact with foodstuffs.

Figure A.4.3. Mechanical properties of alloys of the 5000 series.


8/12/2019 44956_04



The simultaneous addition of iron (which yields a fine-grained structure) and silicon

improves the mechanical properties of aluminium (Figure A.4.4). With their fine grain

structure and good isotropy, these alloys have good formability under difficult conditions,even as foil (between 50 and 200 mm thick). This explains their increasing use as fins for

heat exchangers, spiral tubes, dishes, thin foil, etc. The two most commonly used alloys are

8006 (with added manganese) and 8011.


The main addition is copper, and, in lesser quantities, magnesium and silicon. The

selection criteria for these alloys are generally

– the mechanical strength in the T6 temper,

– the low crack propagation rate in the T4 temper,

– the heat resistance, and

– the aptitude for free machining.

Alloys of this series are used either in T4 temper, or in T6 or T8 temper.

4.5.1. The quenched and naturally aged tempers T4 and T451

Alloy 2017A (formerly called Duralumin) provides average tensile strength but good

machinability. It is widely used in mechanical applications (as extrusions or thick plates).

Figure A.4.4. Effect of iron and silicon content in the annealed (W) temper.


8/12/2019 44956_04


Alloy 2024, with its higher magnesium content, is an improved variant of 2017A, with

superior mechanical properties, good fracture toughness and good resistance to crack

propagation. It is used mainly in aircraft construction as sheet in thin and medium gauges(temper T351) and as extrusion.

4.5.2. The artificially aged tempers T6 (T651) and T8 (T851)

Alloy 2014, with its higher silicon content (0.5–1.2%) has particularly high mechanical

properties in the T6 temper. This alloy is mainly used for aircraft construction and in the

mechanics industry.

Alloy 2214 is a variant of 2014 containing less iron, which improves its fracture tough-

ness and resistance to crack propagation in thick plates for aircraft construction. It is

also used in the mechanics industry and for the manufacture of video recorder drums.

In thick products, alloy 2024 in the T8 temper provides a good level of mechanical

strength and satisfactory resistance to intergranular corrosion in products with a thickness

of less than about 10 mm. Strain hardening between quenching and artificial ageing leads

to an increase in mechanical strength (temper T8). The main applications of this alloy are

in aeronautics and armaments.

Further additions of iron, nickel, manganese and vanadium increase the mechanical

properties at temperatures between 100 and 300 8C. These are alloys 2618A and 2219,

which in the T6 temper provide good stability and creep resistance up to 100–150 8C.Alloy 2618A is used in aircraft construction (including supersonic Concorde aircraft)

and in the mechanics industry.

Alloy 2219 has the highest copper content (6%) of all industrial alloys and additions of

manganese, vanadium, zirconium, and titanium. Strain hardening after quenching

increases the mechanical properties of this alloy, which is available in the tempers T3,

T6 and T8. It has several interesting properties:

– creep resistance and tensile yield strength in the temperature range between 200 and300 8C,

– mechanical properties at cryogenic temperatures,

– arc weldability (TIG and MIG), and

– resistance to stress corrosion in the T6 temper.

It is used for the manufacture of welded tanks for space launcher rockets.

Finally, adding lead and/or bismuth presents a good aptitude for free machining, due to

the fragmentation of turnings; this is the case of alloys 2011 and 2030.

It should be recalled that with the exception of 2219, these alloys cannot be welded by

conventional TIG and MIG techniques. Furthermore, their resistance to corrosion is poor,

and thus they need to be protected if they are to be used in humid environments, and all the

more in aggressive environments.


8/12/2019 44956_04



The two alloying elements of the 6000 series are magnesium and silicon (Figure A.4.5).These alloys show

– good aptitude for hot transformation by rolling, extrusion and forging,

– good resistance to corrosion, especially atmospheric corrosion,

– a high level of mechanical properties which can be further improved by adding silicon

(above the stoichiometric amount in the hardening precipitate Mg2Si) or copper,

– a good aptitude to arc welding and brazing,

– good cold formability (bending of profiles, deep drawing of sheets) in the O temper

and, to a lesser extent, the T4 temper, and

– attractive surface appearance after brightening or anodising.

All these properties account for the extensive use of this alloy series, especially in the

field of metallic fittings.1

These alloys are available

– either as extrusions only: 6005A, 6106, 6056, 6060, 6262,

– or as rolled or extruded semi-products: 6061 and 6082.

Alloy 6060 is the extrusion alloy par excellence. Very complex shapes can be obtained,

and press quenching (T5 temper) can be achieved. Several variants of this alloy with

variable magnesium and silicon content are available, which aim at improving certain

properties or optimising a set of properties such as extrudability, surface appearance,

suitability for anodising, and mechanical properties.

Alloy 6005A is easily extrudable and can be press quenched. In the T5 temper, its

mechanical strength is in the order of 290 MPa. This alloy has remarkable fracturetoughness, and can therefore be used as a structural member, for instance in commercial

road and railway vehicles, and in mechanical applications.

Alloy 6106 is an extrusion alloy that has been specially developed by Pechiney for

many applications related to lightweight constructions. It is very easy to extrude, has a

good aptitude to press quenching and good mechanical strength, in the order of 265 MPa,

which is midway between 6060 and 6005A.

Alloy 6056 in the T6 temper has the highest mechanical properties of this series of

alloys: Rm ranges from 450 to 470 MPa. It is used as reinforcement for car doors.Alloy 6262, a free machining alloy, contains additions of lead and bismuth which

facilitate fragmentation of turnings.

1 The world consumption of extrusions in 6000 series alloys is in the order of 6 million tons per year.


8/12/2019 44956_04


Alloy 6082 has high mechanical properties of 320–340 MPa in the T6 temper. Like

6005A, it is widely used in commercial vehicles, railcars, shipbuilding, in the mechanics

industry and as forging stock.

The mechanical resistance of alloy 6016 in the T4 temper is at a medium level:

220 MPa. It has a good aptitude to deep drawing and is widely used for car bodies.

Alloy 6061 hasmedium mechanical strength (310 MPain T6 temper). It is frequently used

for extruded products (bars, profiles, tubes), cold-drawn, as well as rolled and forged prod-

ucts. It is used for structures requiring both average mechanical strength and good resistance

to corrosion, in diverse fields of technology: transport (railcars, commercial vehicles),

tubing (pipelines), welded boilerwork, mechanics applications, and tubular furniture.


This series comprises two subgroups: alloys with and without copper.

4.7.1. 7000 alloys without added copper

Alloy 7020 is the most widely used alloy for rolled or extruded semi-products in different

fields such as transport, the mechanics industry, and armaments.

In the quenched and artificially aged condition (T5 or T6), i.e. its normal use condition,

its mechanical strength is in the order of 360 – 400 MPa. Its corrosion resistance is

satisfactory, unless it is welded.

Its heat resistance is rather poor as soon as the temperature exceeds 120–130 8C.

Exposure to temperatures above 200 8C can sensitise the alloy to exfoliation corrosion.

Figure A.4.5. Alloys of the 6000 series. Iso-curves of for ultimate tensile strength Rm.


8/12/2019 44956_04


This alloy has satisfactory arc weldability (with filler metal 5356), and after welding,

mechanical properties equivalent to those of the parent metal in the T4 temper can be

achieved. However, it shows a strong sensitivity to exfoliation corrosion in the heat-affected zone, on either side of the welding bead (See Section B.6.4.2 and Figure B.2.11).

This handicap severely limits its use in welded structures to very specific applications that

are subject to frequent inspection.

4.7.2. 7000 alloys with added copper

Adding copper to the aluminium– zinc– magnesium system produces the aluminium alloys

with the highest mechanical resistance in the T6 temper.

Products capable of resisting corrosion in aggressive atmospheres, which are

particularly resistant to stress corrosion in the short-transverse direction can be obtained

by duplex ageing (tempers T73 and T76); however, this leads to a decrease in mechanical

strength of about 20%.

Alloy 7075 is most often used as rolled, extruded, die-forged and hand-forged products

in the fields of aerospace, mechanics, and sport and leisure equipment.

The need for products with a thickness above 80 mm has triggered the development of

7050 and 7010, two variants, which differ from 7075 in that

– chromium has been replaced by zirconium, which facilitates quenching, and– the copper content has been increased, which, after a T73 or T76-type duplex

ageing process, provides a good compromise between mechanical properties and

corrosion resistance.

Alloy 7049A can be considered as one of the commercial aluminium alloys with the

best mechanical properties in the T6 temper. Its average mechanical properties are

– R

p0:

2: 570 MPa– Rm: 650 MPa

– A: 10%

Extrusions and forgings in 7049A are used in the aircraft and armaments industries.

REFERENCES

[1] Develay, R., Proprietes de l’aluminium et des alliages d’aluminium corroyes. Techniques del’inge nieur , fasc. M. 438 (1992), M 439 (1992), M 440 (1992), M 441 (1992), M443 (1989), M

445 (1985), M 446 (1989), M 447 (1989), M 448 (1989).

[2] Demi-produits en aluminium, Pechiney Rhenalu, 1997.


44956_04

Documents

Transcript of 44956_04