Aluminium extruded profiles
Get to know the world of aluminium extruded profiles. Learn about the extrusion process and the different shapes and sections it can create.
1 What is aluminium profile?
Profile
Wrought product that is long in relation to its cross-sectional dimensions and have a form other than that of sheet, plate, rod, bar, tube, wire or foil.
For profiles sometimes the term “shape” or “section” is used [1].
1.1 Aluminium profile forming processes
- Extrusion. Process in which a billet in a container is forced under pressure through an aperture of a die (Fig. 1).
- Drawing. Pulling metal through a die in order to reduce or change the cross-section or to work harden the metal (Fig. 2).
- Cold roll forming (Fig. 3).
1.2 Raw materials
- Extrusion ingot. Ingot, intended and suitable for extruding, typically of solid circular cross-section.
- Extrusion log. Extrusion ingot not cut to length.
- Extrusion billet. Extrusion ingot cut to length.
- Drawing stock.
- Aluminium strip.
1.3 Aluminium profile types
- Extruded profile. Profile brought to final dimensions by extruding.
- Drawn profile. Cold-finished profile brought to final dimensions by drawing through a die.
- Roll formed profile.
Figure 2 – Manufacturing aluminium cold drawn tube from extruded drawing sock [3]:
Methods of tube drawing:
(a) without internal support by sinking;
(b) with internal support by fixed plug,
(c) with internal support by floating plug,
(d) with internal support by moving mandrel
Figure 3 – Roll-formed aluminium profiles. Profiles are made from aluminum strip [4]
2 Aluminium extruded products
Aluminium extruded products include (Fig. 4):
- profiles
- rods/bars (round, square, rectangle, hexagonal)
- tubes (round, square, rectangle)
- stocks for drawing, forging, machining, cold and impact extrusion
3 Aluminium extruded profiles
3.2 Types of aluminium extruded profiles
Solid profile
Profile in which the cross-section does not include any enclosed void (Figure 5c).
Hollow profile
Profile in which the cross section completely encloses one or more voids (Figure 5 b).
Semi-hollow profile
Semi-hollow profile is a solid profile any part of whose cross section is a partially enclosed void the area of which is substantially greater than the square of the width of the gap (Figure 5a).
{a) A semi-hollow die extrudes a shape
that is nearly hollow, partially enclosing a void.
The die set includes a mandrel section and cap section.
(b) A hollow die produces profiles with one or more voids.
The die set includes a mandrel section and cap section.
(c) The solid die stack to produce a solid profile
includes die plate and die backer. The shape is formed by die plate.
3.3 Seamless tubes
Seamless tube is an hollow profile which does not contain any line joints from method of manufacture (Fig. 7).
4 Extrusion aluminium alloys
4.1 Chemical composition
4.2 Mechanical properties
4.3 Aluminium alloys extrudability
4.4 Minimum wall thickness
Figure 11 – Minimum wall thickness for various extrusion presses [7]
5 Dimension and form tolerances
- Precision profile. Profile which fulfils special requirements concerning tolerances on form and dimensions. Aluminium extruded precision profiles of 6060 alloy and 6063 alloy are produced according to EN 12020.
- Structural (standard) profile. Profile commonly used for structural purposes such as angles, channels, H-beams, I-beams, tees, and zees. Aluminium extruded structural profiles of all extrusion aluminium alloys are produced according to EN 755.
5.1 Circumscribed circle diameter
- Circumscribing circle. Circle that will just contain the cross-section of a profile, typically designated by its diameter (CCD – circumscribed circle diameter).
Рисунок 12 – Circumscribed circle diameter (CCD) of the profile for a round billet [5]
5.2 Tolerances on cross-sectional dimensions
Tolerances on the dimensions of the cross section of the profile depend on the type of the dimension. There are the following types of dimensions:
- A: wall thicknesses of “solid part” of the profile;
- B: wall thicknesses of “hollow part” of the profile (encloses the hollow spaces except those between two hollow spaces;
- C: wall thicknesses of “hollow part” of the profole (between two hollow spaces);
- E: the length of the shorter leg of profiles with open ends;
- H: all dimensions (except wall thickness) between points on the cross section of the profile or the centres of open screw holes.
6 Categories of complexity of aluminium profiles
6.1 Shape factors of aluminium profiles
6.2 Complexity of aluminium extruded profiles
7 Aluminium extruded profiles cost
The cost of an aluminum extruded profile is determined, among other things, by the following factors:
- extrusion die cost
- type of profile (solid, hollow)
- extrudability of aluminum alloy (extrusion speed)
- required temper of profile material (press quenching or furnace quenching, natural or artificial ageing)
- level of requirements for dimensional and shape tolerances (EN 755 or EN 12020)
- surface quality requirements (without coating, for powder coating, for anodising).
Sources:
- Global Advisory Group GAG – Guidance “Terms and Definitions” – 2011
- Aluminum Extrusion Technology / P. Saha
- Mechanical Properties and Working of Metals and Alloys / Amit Bhaduri – Springer Series in Materials Science – Volume 264 – 2018
- ALUTECH GROUP
- TALAT 1302
- Die Defects and Die Corrections in Metal Extrusion / S.Z. Qamar, T. Pervez and J. Ch. Chekotu – Metals 2018, 8(6), 380
- https://www.bwcprofiles.co.uk/
- TALAT 2202
- EN 755-9
- EN 12020-2
- Influence of Al Microstructure on Hard Anodising Quality / Tom Hauge, Hydro Aluminium, 2014.
