Aluminum profiles: manufacturing, functions, alloys, types

How to make aluminum profiles

Aluminum profile. It is almost always an extruded aluminum profile.. Much less frequently used other types of aluminum profiles, for example, bent or rolled.

Figure 1.1 – Direct compression method [1]


Figure 1.2 – Typical press for direct extrusion of aluminum alloys [4]

Figure 1.3 – Typical press tool kit for direct compression [1]

Figure 1.4 – Reverse pressing method [1]

Figure 1.5 – Extrusion of hollow sections
with porthole “dies” [1]

Figure 1.6- Pipe pressing method using a matrix and mandrel [1]

 

Figure 1.7 – The share of finished products and process waste
from extrusion aluminum ingot (column) [4]

Output of finished products from aluminum ingot-pillar:

  • 75 % – ready-made profiles;
  • 4,5 % – scrap in the manufacture of aluminum products from aluminum profiles;
  • 4,5 % – blanks for heating matrices; matrix crimping, pressing defects;
  • 11 % – waste of crumpled ends of profiles after stretching machine;
  • 4 % – press residues; 1 % – Waste hot cutting the workpiece to the column


Figure 1.8 – Process wastes aluminum extrusion,
which immediately go to remelting and casting new extrusion ingots [4]

Elements and details of structures, machines and products

Each aluminum profile has its purpose, their properties and characteristics. If it's just a decorative element, the main purpose of which - to be beautiful, looks nice, its main characteristic that - good surface quality, its uniform color decorative coating, powder or anode.

If set for aluminum profile, e.g. - matt colorless anodic coating, it should be a really matt. This is the "haze" must be perfectly homogeneous when viewed from a given distance and at a predetermined angle, without any visible bands, and other visual surface discontinuities. To ensure that all, necessary to apply a special aluminum alloy with a chemical composition, special technology of its manufacture and its special surface treatment technology.

Aluminum profiles, as elements bearing construction or other structures, require special attention to their mechanical characteristics:

  • tensile strength,
  • ductility limit,
  • reduction of area,
  • tough properties.

In this case, important to choose the correct alloy, its condition (degree of autofrettage or heat treatment), as well as the required dimensional accuracy during manufacture.

In other types of profiles, we must take into account such properties, as corrosion resistance in the environment, which will work profile, sometimes - conductivity or heat resistance.


Figure 1.9 – Space frame of the car Audi A8 from aluminum alloys [1]


Figure 1.10 – Design of aluminum profiles
with increased rigidity [1]

Blanks for drawing, cold pressing and forging

Moreover, Extruded aluminum profiles are used as starting templates for such aluminum processing techniques like dragging, cold pressing and forging.

Figure 1.11 – Appointment of aluminum profiles,
including drawing, cold pressing and forging [1]

Figure 1.12 – Drawing of a pipe from a pressed aluminum hollow billet [3]

Alloys of aluminum profiles

Extruded aluminum profiles can be manufactured from a large number of alloys in different states in order, to meet the requirements of various fields of application - from household goods to the space launch vehicles.

Basically, from any deformable aluminum alloy (and even casting) one way or another it is possible to extrude an aluminum profile. However, metal flow through the holes and cavities of the matrix at high temperature compression requires special characteristics of the flow, so that the metal:

  • filling all holes at the outlet of the matrix with the same high speed,
  • I provide the desired microstructure,
  • reaches a predetermined strength and other properties,
  • shaped optimal surface quality.

Therefore, special aluminum alloys are being developed specifically for pressing (extrusion). The chemical composition of these alloys is optimized in this way., that they are the most suited to the conditions of the process of pressing and ensure the required quality of molded products.

In world practice, aluminum profiles from alloys 6xxx series give more 75 % the volume of all sections.


Figure 1.13 – magnesium and silicon content
in aluminum alloys 6060 and 6063,
as well as some other alloys of the 6xxx series [1]

The most popular aluminum alloy profiles – these are alloys:

  • 6060/6063 (AD31) and
  • 6061(AD33).

gaining popularity “more construction” alloys

  • 6005 and
  • 6082 (AD35).

Brand series aluminum 1xxx, for example, 1100, used for parts and products, which is no requirement for strength. They are best compacted – They have the highest compressibility.

3xxx series of alloys, for example, alloy 3103 pipe for compressed fluid lines.

other alloys, are more likely to apply for the production of profiles - is “Duran”:

  • 2017(D1),
  • 2014(AK8),
  • 2024(D16),

and

  • 5083(AMg4.5),
  • 6101,
  • 7005(1915) and
  • 7075.

Figure 1.14 – The chemical composition of some aluminum alloys,
which are produced in the form of pressed products [1]

Figure 1.15 – Mechanical properties of some aluminum alloys,
which are produced in the form of pressed products [1]

Alloy Compressibility: Compression Ability


Figure 2.1 – Relative compressibility of aluminum alloys [1]


Figure 2.2 – Compressibility of various aluminum alloys [1]

The minimum thickness of the profile wall

Effect complexity cross-sectional profile of the alloy 6063 the normal minimum wall thickness /


Figure 2.3 – Recommendations for the minimum wall thickness
profiles of varying complexity alloy 6063 [1]

Figure 2.4 – The minimum wall thickness of aluminum profiles
(solid, pipe, hollow)
for extrusion presses 10-80 MN [2]

Diameter of the circle described Profile

Generalized size aluminum profile is circle diameter, describing its cross-section (figures 3.1 and 3.2). This parameter is called the "circumscribed circle diameter".

 

alyuminievyy-profil- diametr-opisannyyFigure 3.1 – Diameter of the circle described Profile

The diameter of the circumscribed circle (OCD) is really related to the complexity of extrusion of an aluminum profile. During pressing, the metal tends to flow through different parts of the matrix at different speeds: the farther from the workpiece axis, the slower. therefore, the greater the OED, the harder it is to control the size of the aluminum profile.

When pressing large and thin profiles, special, if these thin wall profiles on the periphery of the matrix, you must take special precautions, to metal flow was uniform around the cross section profile. Therefore, with increasing PEO all standards for aluminum profiles reduce the requirements for tolerances geometrical dimensions.

Figure 3.2 – round billet


Figure 3.3 – Rectangular blank for rectangular container [1]


Figure 3.4 – Hollow extruded aluminum profiles,
which are produced using a rectangular container [1]

Types of aluminum profiles

Existing standards for aluminum profiles – for example, Russian GOST 22233-2018 and GOST 8617-91, European EN 755-9 и EN 12020-2 – subdivide the entire range of aluminum profiles into various types:

  • hollow profiles and
  • solid profiles, and
  • S- and U-shaped profiles, or "open-end".

The hollow profile

By definition, these standards are hollow aluminum profiles - those, which have a cross-section at least one closed cavity.


Figure 4.1 – The hollow profile

solid profile

Solid aluminum profiles do not have closed cavities.

Figure 4.2 – Solid profile [1]

Solid matrices have one or more holes and intended for the manufacture of extrusions without cavities. The hole in the solid matrix is ​​exactly the same cross-section of the molded article of aluminum.


Figure 5.1 – Die for pressing solid profiles by direct pressing [1]


Figure 5.2 – Metal flow in direct pressing [1]

Profile with an open end

"Open End" can be like a hollow, and have a solid profile. For these three types of profiles are given different requirements for tolerances geometrical dimensions.

 


Figure 6 – Controlled dimensions of aluminum profiles according to GOST 22233-2018 [5]
(IN 12020-2 [6]: h1 – distance between open ends)

Semi-enclosed and semi profiles

Hollow aluminum profiles include, including, and profiles with so-called semi-closed (half-open) cavities. Often profiles of this type are called semi-closed (half-open). They are partially closed cavity, for example, circle or rectangle, with an entrance to it from one side (figure 6).


Figure 7 – Semi-closed (half-open) profile [1]

Not every partially closed cavity transforms the profile from a solid semi-closed one: its area A must be significantly larger than the square of the width of its entrance b (A > b), depending on the width of the entrance - in 2,0-4,5 times (cm. Figure 6).

“Hollow” die

Hollow and semi-enclosed aluminum profiles are combined in one view, because they are made on the so-called "hollow" dies (figures 7 and 8). Hollow dies are of three types:

  • bridged
  • dies
  • “spider”(spider).

profiles, manufactured in such matrices, have one or more longitudinal welds due to the metal flow around the bridges, that support mandrel. The mandrel determines the internal profile contour. After passing these bridges, metal matrix before exiting again welded in the welding chamber. Welding occur due to high pressure and high temperature. Solid profiles are compressed on a continuous matrix - steel rims with one or more holes with the same cross-section, and that the pressing profile.

Figure 7 – Combined die for pressing semi-closed (half-open) profiles

Figure 8- Combined matrix for pressing hollow profiles

Level of difficulty of aluminum profiles

Each type of profiles – continuum, and semi-hollow – They differ in the types of complexity of their cross-section. This complexity is evaluated by the aluminum profile form factor.

Shape factor

Aluminum profile shape factor is calculated as the area of ​​all surfaces, formed in the pressing unit mass of metal. obviously, that this factor is directly proportional to the length of the cross-sectional perimeter. The shape factor affects the performance of the profile molding, as well as the cost of production and maintenance of matrices. Therefore, it is frequently used presser-makers as a basis for setting prices and the profile gives developers profiles specific tool for comparing alternatives developed aluminum profiles.


Figure 9.1 – Form factors for various types of profiles [1]

Classification of complexity of aluminum profiles

Classification of types of extruded aluminum profiles according to the complexity of their manufacture is as follows. Types of difficulty from A to N are arranged in order of increasing complexity. Each type is illustrated by several examples.

ayuminievye-poofili-kategorii-sloznostiFigure 9.2 – Types of difficulty aluminum profiles

The complexity of pressing increases in the following order of profile types:

  • Bars – simple or profile.
  • Standard aluminum extrusions and simple solid profiles,
  • Poluzamknutыe profiles,
  • Profiles with complex matrices tongues,
  • tubes,
  • Simple hollow profiles,
  • Complex hollow profiles.
  • Wide hollow profiles.

Optimization of aluminum profiles

Figure 10 – Optimization of the cross-section of aluminum profiles [2]

Price aluminum profiles

Price aluminum profiles usually directly related to its category of complexity. However, at the same time, multi-functional aluminum profiles open up the possibility of more effective technical, and their higher price is often quite justified.

Sources:

  1. TALAT 1302
  2. TALAT 2202
  3. Drawing Types – University of Liverpool
  4. Presentation of the company SAPA
  5. GOST 22233-2018
  6. EN 12020-2