Aluminium and its alloys:
Aluminium is not found as a metal in the natural world, but is extracted from the mineral bauxite. It was given its name because of the French locality of Les Baux where it was mined for the first time in 1821.
Bauxite contains iron and silica oxides and its concentration of alumina (Al2O3) is approximately 50%. The procedure for obtaining aluminium from bauxite is divided into two processes.
- The Bayer process to extract alumina from bauxite.
- The Hall-Héroult electrolysis process to extract the aluminium from the alumina.
In quantitative terms, two kilos of alumina can be extracted from four kilos of Bauxite, which in turn yields one kilo of aluminium
After the electrolysis process, primary aluminium is obtained with a purity of 99.6%. This aluminium is sent to the foundry to prepare the different alloys.
The extrudable alloys belong to the 2XXX, 6XXX and 7XXX alloy families. These are suitable alloys for tempering and for thermal treatment, they offer high mechanical strengths when raised to high temperatures (solubilization), followed by rapid cooling in water for the 2XXX and 7XXX alloy families and in air for the 6XXX alloy family, followed by ageing at an intermediate temperature.
The 6XXX alloy family, because of its characteristics, is the most widely used in extrusion.
These alloys are thermally tempered, the most widely used are 6060 and 6063, also known as Al-Mg-Si 0.5. These have the best attributes from extrusion, in terms of the possibility of carrying out complex geometries and with fine thicknesses, as well as high extrusion speeds. Ideal for enclosures, and semi-structural uses.
- They are resistant to corrosion.
- They are weldable.
- Surface treatments can easily be applied: polishing, anodized oxidation, and painting.
- Alloy 6005 (Al-Mg-Si 0.7) and its derivatives present an intermediate mechanical strength. It offers reliable characteristics for structural profiles.
- Alloy 6082 presents the best mechanical characteristics of the 6000 series.
In ITESAL, we have a productive capability of 17,000 Tn.
In ITESAL we can extrude aluminium profiles according to the following specifications:
- We have the ISO 9001 and the 140001 Quality Certifications.
- We extrude in accordance with European Standards EN 755-9 and EN 12020
- We apply thermal treatments T4 – T5 and T6 in accordance with European Standard EN 755-2:2009
Our extrusion capacities are as follows:
- Extrusion capacities according to the attached graph.
- Cut lengths of between a minimum of 3 metres and a maximum of 12.5 metres. The standard length of cut is 6 metres.
In ITESAL, we have an ultimate generation vertical lacquering plant that allows us to offer a high-quality lacquered profile and to offer a leading service on the market.
Lacquering is done with polyester paint with a gloss, satin sheen and lustre finishes.
The lacquering options are as follows:
- Maximum length: 7,090 mm
- Minimum length: 4,000 mm*
- Maximum dimensions: 200x100 mm
- Maximum weight by bar: 20 Kg
Profile lacquering is done in accordance with QUALICOAT CLASE SEASIDE lacquering specifications and quality seal. The specifications to comply with this quality mark are as follows:
- Chemical pre-treatment acid attack > 2gr/cm2, Zirconium (chrome free) conversion layer
- The thickness of the layer is measured in accordance with standard EN ISO 2360:2003, the minimum required value of which is 60 microns.
- Adherence to standard EN ISO 2409:1994, no poor adhesion is acceptable.
- Acetic salt spray test, in accordance with standard ISO 9227:2007; a test was performed over 1,000 hours.
- Impact, bending and deep-drawing test, after completing these tests, the lacquering should present no peeling or cracking.
Imitation wood lacquering
In ITESAL, we have a lacquering plant for wood finishes in which over 30 different finishes are programmed weekly.
The maximum dimension of the profiles is 7 metres.
Anodization is an electrochemical process in which a uniform layer of oxide is coated onto the aluminium that fulfils a dual role of decorating the profile with a specific colour and protecting it against abrasion and oxidation.
The anodization process consists of the following phases:
- Initial mechanical or chemical treatment.First of all, mechanical scouring or an acid bath is completed to remove possible uneveness that the profile might have and to prepare its initial surface finish.
- Degreasing and cleaning, by means of an acid bath to ensure a proper anodization process.
- Anodization, is the electrochemical process that carries out controlled oxidization.
- Colouring (optional).
- Sealing, the pores in the oxide are closed to prevent the oxidation process from continuing.
- Repolishing (optional), in this process, lustring of the profile surface gives it a shiny finish.
Cutting and machining operations
We use ultimate generation numerical control machine centres equipped with WIDIA® discs (a tungsten carbide-cobalt alloy with high-hardness and thermal resistance) for cutting and machining that guarantee quality cutting and machining operations.
The working sizes of the numerical control machining centre have a length of 6000 mm and a width of 800 mm. The field of operation of the machinery is 180 degrees, which permits all sorts of operations to be completed.
There are machining operations that can be done with dies and hydraulic presses.
In each of the processes, the machining operations are studied and the project is analyzed in view of the quantities of units to produce and their difficulty. An acceptable machining process is designed with a Computer Numerical Control (CNC) Machine and dies for the best optimization of the project, maximizing quality.
Thermal Break ensures an optimum thermal barrier that prevents the loss of heat or cold from within the living quarters towards the outside, with the consequent economic savings in their acclimatization.
Thermal Break consists of two aluminium profiles joined by polyamide rods. Polyamide is a compound formed by a polymer of high thermal insulation that is reinforced with glass fibre, giving it good mechanical performance.
The assembly process consists of the following points:
- Knurling: consists in serrating the housing of the aluminium profile into which the polyamide strip will be inserted. The purpose of knurling is to secure the polyamide strip against the aluminium profiles.
- Insertion of the polyamide strips in the aluminium profiles: the polyamide strip is introduced into the anchors on the aluminium profile, especially designed to ensure a solid union between the aluminium profiles and the polyamide strips.
- Fasteners: The fasteners are the parts of the aluminium profile that are locked in to secure the polyamide strip in position, in such a way as to join the two profiles with the polyamide strip, forming a very solid joint.
The machinery to perform the assembly of the profiles with Thermal Break consists of two ALUROLLER profile assembly machines equipped with an artificial vision system to enable geometric control of all the profiles that are assembled to achieve maximum quality in the process.