This document provides an overview of an aluminium extrusion training workshop held by Gulf Extrusions. It discusses: 1. An introduction to Gulf Extrusions, the largest aluminium extruder in the MENA region. 2. The aluminium extrusion process and why aluminium is commonly used. It describes the extrusion equipment and process steps. 3. Aluminium alloys used in extrusion, including the 6xxx series. It covers tempers, properties, specifications and the effects of heat treatment.

1. Aluminium Extrusion Training
Aluminium Extrusion Training
By: Sajid Hussein
By: Sajid Hussein
QMEA 1st Powder coating Workshop
QMEA 1st Powder coating Workshop
Date: 25.01.2011

2. OBJECTIVES
1 Introduction to Gulf Extrusions
1. Introduction to Gulf Extrusions
2 Aluminium Extrusions Process
2. Aluminium Extrusions Process
3 Al i i All & H t T t t
3. Aluminium Alloy & Heat Treatment
4. Extrusion Surface Defects
5. Extrusion Dimension Tolerances

3. 1. Introduction to Gulf Extrusions
• Over 32 Years of excellence in in MENA region
• 480 Skilled employees
• 60,000 MT production capacity
, p p y
• Extrusion, Powder coating, Anodizing & Thermal
Crimping
Crimping
• Largest Press in MENA region ‐ 4400 MT
I h bli h d R&D f ili i
• In‐house established R&D facilities
• Over 15,000 different extruded shape

4. 2. Aluminium Extrusion Process

5. Why Aluminium???
• The most common metal in nature
• It is light with a density (1/3rd of steel)
• Can be easily recycled‐5% of the original energy consumption
Can be easily recycled 5% of the original energy consumption
• It can be extruded
• Aluminium alloys can be produced with a range of strengths
Aluminium alloys can be produced with a range of strengths
• It is easy to machine
• It can be joined using the normal methods of welding
It can be joined using the normal methods of welding,
adhesive bonding, riveting
• It can be given a range of decorative and protective surface
g g p
finishes

6. Why Aluminium Extrusions
• Practically unlimited range of shapes
• Designer can incorporate the metal where it is needed
• Functions can be included to reduce the number of
components
p
• Low tooling costs

7. Extrusion Processes ‐ classification
¾ By Direction: DIRECT
DIRECT INDIRECT
INDIRECT
¾ By Operating Temp.: HOT
HOT / COLD
COLD
¾ By Equipment: HORIZONTAL
HORIZONTAL / VERTICAL
VERTICAL
¾ By Equipment: HORIZONTAL
HORIZONTAL / VERTICAL
VERTICAL

8. Aluminium Extrusion Press

9. Basic Direct Extrusion Process
STEM
BILLET
CONTAINER
BILLET
STEM
CONTAINER
STEM STEM
CONTAINER CONTAINER
BILLET LOADING UPSETTING
STEM
EXTRUSION SHEARING

10. Specification needed Prior to Extrusion
1. Application
2. Alloy
12.Wall Thickness Variations
13.Number of Cores
14 T R i
3. Mechanical Properties
4. Weight per Metre
5 Circumscribing Circle
14.Tongue Ratios
15.Exposed Surfaces
16 Details that will affect Surface
5. Circumscribing Circle
6. Cut Length
7. Tolerances
16.Details that will affect Surface
Finish
17.Custom Tooling
8. Surface Finish
9. Quantity
18.Back End Defect
19.Charge Weld
20 Mill Fi i h A di d O C t d
10.Packaging
11.Minimum Wall Thickness
20.Mill Finish, Anodised Or Coated
21.Fabrication

11. Extrudability
Aspects that are key to the extruders are:
• Alloy Suitability based on end application
Alloy Suitability based on end application
• Design of profiles
• Extrusion to the desired tolerances
• Finish required
Finish required
• Can all the extrusion needs be accomplished
at a feasible cost

12. Preheating
• Billet Loading
– aluminium logs bundle is loaded on to the loading tables
• Die Preheating
– Relevant dies as per the production programme are loaded into
the die oven, heat the Dies between 430°C to 470°C
• Preheating
– The billet logs are preheated as per the following parameters:
Dies : Hollow Semi Hollow Flat
1st billet temp : 510 – 530°C 490 – 510°C 480 ‐ 500°C

13. Extrusion
– Start up of Press
• Switch on press power controls ‐ PICOS,CADEX & handling system
Th i t d d l t l t t i
• The press is operated on dry cycle at least twice.
• Die oven temperature is set between 430°C ‐ 470°C.
• All the movements of ancillary equipments such as slat conveyor
• All the movements of ancillary equipments such as slat conveyor,
puller saw machine, belt conveyors in cooling beam and lift off
arms is checked
– Setting the Billet Length & Number of Billets
– Lubrication of Dummy Block
– Production

14. Post Extrusion
• Stretching
– After cooling profiles are stretched to eliminate bowing effects
and waviness
and waviness.
– This is done by holding two ends in the stretcher and stretching
to obtain optimum straightness by stretching operator and tail
p g y g p
end operator.
– Profiles from multi cavity dies may be stretched together.
– After stretching, the profiles are arranged in batches. The width
of the batch should not exceed the width of the cold saw
conveyor
conveyor.

15. Post Extrusion Contd…
• Cutting
– The profiles are cut to the specified lengths by the operator
St k d i till th i t fi i h/ ft/ h d
– Stacked in stillages as per the requirement – finish/ soft/ hard.
Hard materials are sent for aging.
– The cutting operator fills the necessary information in
The cutting operator fills the necessary information in
Production Card such as number of lengths and stillage number.
– The scrap generated during the process is sent to re‐melting
department.
– Lubricated saws are equipped with delivery systems for optimal
efficiency and cut surface
efficiency and cut surface.
– Automatic devices clamp profiles in place for sawing. Saw chips
are collected for later recycling.
y g

16. Aging
• Extrusion alloys reach their optimal strength through the process of
i ti k h d i
aging, sometimes known as age‐hardening
• Natural aging occurs at room temperature
• Artificial aging takes place through controlled heating often
• Artificial aging takes place through controlled heating often
referred to as precipitation heat‐treating
• When the profile emerges from the press it is in a semi‐solid state,
p g p ,
but rapidly solidifies as it cools or is quenched (whether by air or
water).
• Non‐heat‐treatable alloys ‐ natural aging and cold working.
• Heat‐treatable alloys ‐ controlled thermal treatments
Eith th i th if i it ti f
• Either way, the aging process ensures the uniform precipitation of
fine particles through the metal, yielding maximum strength,
hardness, and elasticity for the specific extrusion alloy
y p y

17. Extrusion Tooling

18. Dies
• Dies are divided into two groups:
– Dies for Solid Extrusion
– Dies for Hollow Extrusion

19. Dies – Solid Extrusion

20. Dies – Hollow Extrusion
Dies for hollow extrusion consist of two parts
• A port through which aluminium flows
A port through which aluminium flows
• A mandrel over which the aluminium rewelds to form the extrusion’s outside
surface

21. Three Piece Tool Stack
Die Ring Die and
Backer
Bolster
BOLSTER
DIE RING SUB BOLSTER
Backer
Sub bolster
DIE BACKER

22. Tool Stack With Insert Bolster
Die Ring Die and Insert
INSERT BOLSTER HOLDER
DIE RING
g Die and
backer
Insert
bolster
Insert
bolster
holder
DIE BACKER INSERT BOLSTER
Sub
bolster

23. Two Cavity Flat Die with Backer
Die-plate forms the Backer‐ provides
extruded profile
Die Number
additional support to the
die to reduce deflection
TONGUE DEFLECTION
UNDER LOAD
NO LOAD
Dies deflect under the high
Tongue support
in backer
Dies deflect under the high
stresses. The die backer
and the bolster should be
designed to give maximum
Cavity identification
Tongue with support to
reduce deflection
Die aperture
designed to give maximum
support through the tool
stack

24. Material flow is fastest in the center of the container
CONTAINER
CONTAINER
STEM
BILLET
DIRECT EXTRUSION

25. 3 Aluminium Alloys & Heat Treatment
3. Aluminium Alloys & Heat Treatment

26. Classification of Aluminium Alloys
Most Aluminium Extrusions are made from the alloy
series listed below:
• 1xxx series – Aluminium of 99% minimum purity
• 1xxx series – Aluminium of 99% minimum purity
• 3xxx series – Aluminium + Manganese
• 5xxx series – Aluminium + Magnesium
• 6xxx series – Aluminium + Magnesium + Silicon
• 7xxx series ‐ – Aluminium + Zinc + Magnesium

27. Properties – Achieved when alloyed with metals

28. Chemical Composition 0f 6xxx Series

29. Various Tempers
The 6xxx series has good extrudability and can be solution heat
treated during hot working at extrusion temperature
F – Extruded profile is not subjected to heat treatment, just air
l d
cooled
O – Extruded profile is softened, annealed at 350 – 500 °C for 1–5hrs
T1 Extruded profile is cooled from an elevated temperature and
T1 – Extruded profile is cooled from an elevated temperature and
naturally aged
T3 – Solution heat treated, Cold worked and naturally aged to stable
3 So ut o eat t eated, Co d o ed a d atu a y aged to stab e
condition
T4 – Extruded profile is naturally aged at 20°C to a stable condition
T5 – Extruded profile is cooled from extrusion temperature and
artificially aged, typically 160 ‐190°C, for 4 – 10 hrs
T6 E t d d fil i l ti h t t t d d tifi i ll d
T6 – Extruded profile is solution heat ‐ treated and artificially aged

30. Alloy Specification – AA 6060

31. Alloy Specification – AA 6061

32. Alloy Specification – AA 6063

33. Alloy Specification – AA 6005 A

34. Alloy Specification – AA 6082

35. Important Parameters ‐ Extrusion
• The most important parameters in Extrusion
are:
–Temperature
T
–Temperature
–Temperature
p

36. Exit Temperature Profile in Extrusion
570
•Although heat is lost to the die
560
550
540
O
RE
C
g
and container during extrusion
the heat generated during the
530
520
EMPERATUR
deformation process raises the
exit temperature well above the
billet temperature
510
500
490
EXIT
TE
billet temperature.
•During extrusion the exit
t t t b hi h
490
480
470
G
temperature must be high
enough to dissolve the
magnesium silicide particles
EXTRUDED LENGTH magnesium silicide particles
ISOTHERMAL EXTRUSION IS KEY TO UNIFORM PROPERTIES

37. Contd..
• During Extrusion the exit temperature must be high enough to
dissolve
SOLIDUS
600
dissolve
the magnesium silicide particles
SOLVUS
600
C
DISSOLVES
Mg Si
IN ALUMINIUM
2
o
ALUMINIUM
400
TEMPERATURE
o
PLUS Mg Si
2
200
0.5 1.0 1.5 2.0
SOLUBILITY OF Mg Si IN ALUMINIUM
2

38. Quenching after Extrusion
• After extrusion the section must be cooled quickly enough to
keep the magnesium and silicon dissolved in the aluminium
Solvus temp (545 C)
6061
• Low Quench Sensitivity
Alloy ‐ 6060/6063
Cooling Rate ‐ 50oc/minute
p ( )
450
550
ure
C
Precipitation occurs
Cooling Rate 50 c/minute
Comples Extrusion
• High Quench Sensitivity
350
Quench rate
too slow
Temperatu
ec p tat o occu s
Alloy ‐ 6082/6061/6005A
Cooling Rate ‐ 250oc/minute 150
250
Critical Quench Rate
for 6061 300 C/minute
Recommended
quench rate
650 C/minute
Time (Minutes)
1.0
0.1 10 100 1000
Typical C Cooling Curve for 6061 alloy

39. Quenching after Extrusion

40. Age Hardening
•When aluminium magnesium silicon alloys are age‐hardened the following precipitation
sequence occurs:
Clusters Needles Rods
•The clusters and needles strengthen the alloy, whereas rods reduce the strength
•The cooling rate after extrusion, the age‐hardening temperature and the time, control
the size and distribution of the precipitates
p p

41. High Mechanical Properties
• High Mechanical Properties require High Alloy Content ‐ AA
6082, AA 6061, AA 6005A
Hi h St th All
• High Strength Alloys are:
¾ High Quench Sensitive
¾ Sl E i S d
¾ Slow Extrusion Speeds
¾ High Extrusion Pressures
¾ f h
¾ Poor Surface Finish
¾ Challenge to extrude Complex sections
• For the same Temper, the UTS values are in this order
AA 6068 > AA 6005 > AA 6063 . AA 6060

42. Mechanical Properties Comparison
Alloy 6060 6063 6005 A 6082
Temper T4 T6 T4 T6 T66
T6
Solid
T6
Hollow
T4 T6
Proof Stress Rp
Proof Stress Rp
0.2
60 150 65 170 200 225 215 110 215
Tensile Strength
R
120 190 130 215 245 270 255 205 290
Rm
Elongation A5% 16 8 14 8 8 8 8 14 8
Webster B
5 10 5 12 13 14 14 11 15
Webster B
Hardness
5 10 5 12 13 14 14 11 15
• Proof Stress and Tensile strength in Mpa (min)
g p ( )
• Note Values depend on wall thickness ‐ see standard
• Young's Modulus for all alloys approximately 70,000 Mpa

43. 4 Extrusion Surface Defects
4. Extrusion Surface Defects

44. Extrusion Surface Defects
Extrusion surface defects that effect the quality of powder
q y p
coated aluminium:
– Blisters
– Pickups
– Tearing
– Graphite Pickups
– Stains
– Die lines
– Twists / Bends
– Orange Peel

45. Surface Defects – Blisters
Entrapment of air/gases/moisture in the extrusion chamber results in the
f i f bli /b bbl h f f l i i
formation of blisters/bubbles on the surface of aluminium.
This is best avoided by a burp cycle

46. Surface Defects – Pickups
Inclusions in the billet, inadequate homogenization treatment, die deflection
d bill l i h f f l i i
and billet temperature results in spots on the surface of aluminium
This is best avoided by good nitriding practices, die steel and inert atmosphere

47. Surface Defects ‐ Tearing
Melting of Magnesium Silicides (MgSi2) results in tearing on the surface of
2
Aluminium
This is best avoided by reducing the extrusion speed and reducing the billet
temperature
temperature

48. Surface Defects – Graphite Pickups
Friction between the profile and graphite on the run out table results in
dh i f hi i l h l i i f
adhering of graphite particles on to the aluminium surface
This is best avoided by reducing the extrusion speed and reducing the
billet temperature
billet temperature

49. Surface Defects – Stains
Oil stains left over after extrusion result in appearance of a distinct patch on
h f f l i i
the surface of aluminium
This is best avoided by complete pretreatment of extruded aluminium prior
d i / f
to powder coating / surface treatment

50. Surface Defects – Die Lines
Prominent lines / streaks /longitudinal depressions / protrusions on the
f f l i i d i f i di f l d b h
surface of aluminium due to imperfections on die surface, also caused by the
interaction of the die land area
This is best avoided by mechanical treatment of this section, die correction
and polishing

51. Surface Defects – Twists / Bends
Improper centering of die cavities, non uniform billet heating resulting in non
if di ib i d i d i ki
uniform temperature distribution, and improper support during stacking
results in twists / bends on surface of aluminium
This is best avoided by proper centering of the die cavities to maintain equal
metal flow for all sections

52. Surface Defects – Orange Peel
Porous appearance on the surface of aluminium very much like the skin of an
h i i j i & d i d i
orange having minute projections & depression due to improper pressure
and
current settings
g
This is best avoided by maintaining proper pressure and current settings in
the powder coating process

53. 5 Extrusion Dimensional Tolerances
5. Extrusion Dimensional Tolerances

54. Basics to Dimensions & Tolerances
• A complex section need not be a difficult extrusion, but a
simple section can be a difficult extrusion
EN755 9 2008 l t l
• EN755‐9 : 2008– general tolerances
• EN 12020‐2: 2008 tighter tolerances for specific applications
• Why do we need tolerances?
Extrusion is a hot working process
– Extrusion is a hot working process
– Extrusion is a hot working process
– Residual Stresses during cooling distort the sections
– Dies wear
Dies wear

55. Factors – Section Size
• Factors that limit section size are:
– Container draw: maximum diameter that can be taken from billet
– Extrusion ratio: area of container / area of section
/
– Extrusion factor: circumscribing circle / section thickness
Sh f t i h / ti l
– Shape factor: periphery / cross sectional area

56. Basic Rules
1. Avoid sudden changes in metal thickness
2 Keep sections symmetrical
2. Keep sections symmetrical
3. Avoid sharp corners
4. Avoid narrow slots or grooves
5. It is easier to control metal dimensions than space
dimensions

57. What is to be achieved
• Correct shape within the dimensional tolerances
• Acceptable surface finish
Acceptable surface finish
• Specified mechanical properties
• Maximum productivity
• Maximum recovery

58. EN‐755‐9 Linear Dimensions ‐ Alloy Group 1
E H E
H
H
H
H
H
CD
Di i H Tolerances on H for circumscribing circle CD
Over
Up to and
including CD
?
100 100<CD
?
200 200<CD
?
300 300<CD
?
500 500<CD
?
800
10 ±0.25 ±0.30 ±0.35 ±0.40 ±0.50
10 25 ±0.30 ±0.40 ±0.50 ±0.60 ±0.70
Dimension H Tolerances on H for circumscribing circle CD
25 50 ±0.50 ±0.60 ±0.80 ±0.90 ±1.0
50 100 ±0.70 ±0.90 ±1.1 ±1.3 ±1.5
100 150 ±1.1 ±1.3 ±1.5 ±1.7
150 200 ±1.3 ±1.5 ±1.8 ±2.0
150 200 ±1.3 ±1.5 ±1.8 ±2.0
200 300 ±1.7 ±2.1 ±2.4
300 450 ±2.8 ±3.0
450 600 ±3.8 ±4.2
600 800 ±5 0
600 800 ±5.0

59. EN‐755‐9 Linear Dimensions ‐ Alloy Group 2
E H E
H
H
H
H
H
CD
C
Over
Up to and
including CD
?
100 100<CD
?
200 200<CD
?
300 300<CD
?
500 500<CD
?
800
10 ±0.40 ±0.50 ±0.55 ±0.60 ±0.70
Dimension H Tolerances on H for circumscribing circle CD
10 25 ±0.50 ±0.70 ±0.80 ±0.90 ±1.1
25 50 ±0.80 ±0.90 ±1.0 ±1.2 1.3
50 100 ±1.0 ±1.2 ±1.3 ±1.6 ±1.8
100 150 ±1.5 ±1.7 ±1.8 ±2.0
150 200 ±1.9 ±2.2 ±2.4 ±2.7
200 300 ±2.5 ±2.8 ±3.1
300 450 ±3.5 ±3.8
450 600 ±4.5 ±5.0
600 800 ±6.0

60. EN‐755‐9 Wall Thicknesses ‐ Alloy Group 1
B
A
B
B
A
C
B
CD
Over
Up to and
including CD
?
100 100<CD
?
300 CD
?
100 100<CD
?
300 CD
?
100 100<CD
?
300
Nominal wall
thickness A,B,C
Tolerances on wall thicknesses
Wall thickness A
Circumscribing circle
Wall thickness B
Circumscribing circle
Wall thickness C
Circumscribing circle
g
1.5 ±0.15 ±0.20 ±0.20 ±0.30 ±0.25 ±0.35
1.5 3 ±0.15 ±0.25 ±0.25 ±0.40 ±0.30 ±0.50
3 6 ±0.20 ±0.30 ±0.40 ±0.6 ±0.50 ±0.75
6 10 ±0.25 ±0.35 ±0.60 ±0.8 ±0.75 ±1.0
10 1 ±0.30 ±0.40 ±0.8 ±1.0 ±1.0 ±1.2
15 20 ±0.35 ±0.45 ±1.2 ±1.5 ±1.5 ±1.9
20 30 ±0.40 ±0.50 ±1.5 ±1.8 ±1.9 ±2.2
30 40 ±0.45 ±0.60 ±2.0 ±2.5
40 50 ±0 70
40 50 ±0.70

61. EN‐755‐9 ‐ Flatness
W1
F
F1
t
W
Width W
Deviation F
Over
Up to and
including
30
30 60
Solid Profiles
0.20
0.30
Wall thickness t> 5
0.20
0.30
Wall thickness t
?
5
0.30
0.40
Hollow Profiles
60 100
100 150
150 200
200 300
300 400 1 60
1 60
0.40
0.60
0.80
1.20
0.40
0.60
0.80
1.20
0.90
1.20
1.80
2 40
0.60
300 400
400 500
500 600
600 800 3.00 3.00
1.60
2.00
2.40
1.60
2.00
2.40
3.00
3.60
4.00
2.40

62. EN‐755‐9 ‐ Angular Deviation
Up to and including
Width W
Maximum allowable deviation Z from a right angle
30 0.4 0.4
Over
2 6
120
180
30
50
80
180 2 2
240 2 6
80 1 1
120 1.4 1.4
30 0.4 0.4
50 0.7 0.7
2.6
3.1
3.5
180
240
300
240 2.6
300 3.1
400 3.5

63. EN‐755‐9 ‐ Straightness
300
Ruler
Ht
Hs
L
Straight Edge

64. EN ‐ 12020‐2 ‐ Linear Dimensions
H E
H
H
H
H
H
CD
Dimension H Tolerances on H
over upto/inc Except open ends E≤60 E60<E≤60
- 10 ±0.15 ± 0.15 a
10 15 ±0.20 ±0.20 a
15 30 ±0.25 ±0.25 a
Tolerances on H (open ends)
15 30 0.25 0.25 a
30 45 ±0.30 ±0.30 ±0.45
45 60 ±0.40 ±0.40 ±0.55
60 90 ±0.45 ±0.45 ±0.65
90 120 ±0.60 ±0.60 ±0.80
120 150 ±0.80 ±0.80 ±1.00
150 180 ±1.00 ±1.00 ±1.30
180 240 ±1.20 ±1.20 ±1.50
240 300 ±1.50 ±1.50 ±1.80

65. EN ‐ 12020‐2 – Wall Thickness
B
A
B
B
C
A
C
B
CD
Tolerance on wall thickness
over upto/inc 0 to 100 100 to 300 0 to 100 100 to 300
- 1.5 ±0.15 ± 0.20 ± 0.20 ± 0.30
Nominal wall
thickness
Wall thickness A for
circumscribing circle CD
Wall thickness B or C for
circumscribing circle CD
Tolerance on wall thickness
1.5 3 ±0.15 ±0.25 ±0.25 ±0.40
3 6 ±0.20 ±0.30 ±0.40 ±0.60
6 10 ±0.25 ±0.35 ±0.60 ±0.80
10 15 ±0.30 ±0.40 ±0.80 ±1.00
15 20 ±0.35 ±0.45 ±1.20 ±1.50
20 30 ±0.40 ±0.50
30 40 ±0 45 ±0 60
30 40 ±0.45 ±0.60

66. EN ‐ 12020‐2 – Convexity / Concavity
W1
F
F1
t
W
Maximum allowable deviation F
Width W
Over Upto/inc
30 0.20
30 60 0.30
60 100 0.40
100 150 0.50
150 200 0.70
200 250 0.85
250 300 1 00
250 300 1.00

67. EN ‐ 12020‐2 – Twist
Over Up to/inc to 1000
1000 to
2000
2000 to
3000
3000 to
4000
4000 to
5000
5000 to
6000 over 6000
25 1.00 1.50 1.50 2.00 2.00 2.00
Width W Twist tolerance T for specified length L
25 50 1.00 1.20 1.50 1.80 2.00 2.00
50 75 1.00 1.20 1.20 1.50 2.00 2.00 subject
75 100 1.00 1.20 1.50 2.00 2.20 2.50 to
100 125 1.00 1.50 1.80 2.20 2.50 3.00 agreement
100 125 1.00 1.50 1.80 2.20 2.50 3.00 agreement
125 150 1.20 1.50 1.80 2.20 2.50 3.00
150 200 1.50 1.80 2.20 2.60 3.00 3.50
200 300 1.80 2.50 3.00 3.50 4.00 4.50

68. Thank You
Thank You
Time for Test?