It is a ductile metal in group IIIA with atomic number 13 and symbol Al in the periodic table. Aluminum, which is a soft and light metal, has a matte silvery color.
It gets its color from the thin oxide layer formed on it when exposed to air. It shows superior resistance against oxidation (rusting) thanks to its passivation feature. Other advantages of aluminum:
- 3 times lighter than steel
- good conductor
- It looks aesthetic
- High elasticity and impact resistance at low temperatures
- Conducts electricity and heat as well as copper
- It takes shape easily; can be extruded, cast, rolled
The earth’s crust is 46.1% oxygen (gas) and 28.2% silicon (semi-metal) by weight. After these two elements, the third most dominant element by weight is aluminum with 8.2%. Therefore, aluminum is the most dominant metal by weight among the elements in the earth’s crust. It is also the most used metal after aluminum, iron and steel.
In addition to architectural applications and construction industry; They have common usage areas in space, aircraft, transportation vehicles, electricity, packaging, electronics, machinery, chemistry and food industries.
Although aluminum is the third most abundant element on earth after oxygen and silicon, its industrial production was realized in 1886 with the introduction of the electrolysis method.
Aluminum, like other commonly used metals such as iron, lead and tin, is found in nature as compounds. The first person to separate and obtain aluminum from its oxide compound was Sir Humphrey Davy in 1807. Later, Hans Christian Oersted, Frederick Wöhler and Henri Sainte-Clairre Deville introduced innovations in the production of aluminum.
The industrial-scale production of aluminum started in 1886 with the electrolysis method of Charles Martin Hall in the USA and Paul T. Heroult in France, unaware of each other. Since this is the method still used today, the year 1886 is considered to be the beginning of the aluminum industry.
With the discovery of the dynamo by Werner Von Siemens in 1886 and the discovery of the Bayer Process (Bayer Method) by KJBayer in 1892, which enables to obtain alumina from bauxite, the industrial production of aluminum has become very easy and this is the youngest metal, the most abundant metal in the world after iron and steel. It was the second metal used.
When the price, durability and lightness properties of aluminum are evaluated together, aluminum emerges as the most optimal material for many sectors. Aluminum is a 100% recyclable material without losing any of its original properties. 75% of the aluminum produced in the world is still in use and 5% of the energy used in primary aluminum production is used in the recovery of aluminum. Considered together, this comes to the fore with its sustainability and environmentalism.
Aluminum is highly resistant to weather conditions and corrosion. Aluminum has a natural anti-corrosion coating. In addition, the desired surface appearance is achieved by anodizing (controlled oxidation).
Since aluminum profiles are light and durable, and have a very high application sensitivity, they offer architects customized design possibilities. In other words, aluminum profiles can be produced in very precise dimensions.
Aluminum has a high chemical resistance by nature, meaning it is easy to maintain and is lighter and cheaper than copper.
Aluminum sheet and extruded building materials used in the construction industry have a significant share in the total aluminum consumption.
Properties of Aluminium
Although the physical and chemical properties of aluminum are given below, it would be misleading to use only these values without defining the chemical composition, production process and hardening stages of aluminum, which will generally appear as an alloy.
Atom numarası 13
Kristal yapısı Yüzey merkezli kübik
Maddenin hali katı
Elektrik direnci 26,50 nΩ·m (20°C’de)
How to Obtain Aluminum?
Aluminum has been obtained by the same method all over the world for a century. The production of aluminum takes place in two stages. In the first stage, “Alumina (Aluminum Oxide)” is obtained from bauxite ore with the Bayer Method. In the second step, aluminum is obtained from alumina by electrolysis. Alumina plants are usually installed near bauxite ores. The bauxite ore extracted from the mine is treated with lye to produce aluminum hydroxide. Insoluble residues (red mud) formed as a result of this process are separated and “alumina” is obtained by calcination of aluminum hydroxide.
The next step is the conversion of “alumina” to “Aluminum”. Alumina, which has the appearance of a white powder, is taken to special places called cells where the electrolysis process will be performed. The aim here is to separate aluminum from oxygen. For the electrolysis process, a direct current of 4-5 volts is applied. The process is completed by removing the aluminum accumulated at the bottom.
Generally, 4 units of bauxite are obtained from 2 units of alumina and 1 unit of aluminum is obtained from 2 units of alumina by weight.
The energy consumption, which was 42.000 kWh for each ton of primary aluminum produced in the early days, has decreased to an average of 16.500 kWh/t today. This value becomes 13,000 kWh/t when working with the latest technology.
Primary aluminum production
The aluminum obtained by the above-mentioned processes is defined as “Primary Aluminum”.
Secondary aluminum production
Thanks to the fact that the recovery of aluminum is economical compared to obtaining it from its ore and its 100% recyclability, the importance given to recovery from scrap has increased over time, and this method is called “Secondary Aluminum” production.
Secondary aluminum production is more economical as it requires 5-8% less energy than primary aluminum production.
Classification of Aluminum Products by Production Method
Aluminum is converted into various semi-products and products by extrusion, rolling and casting processes.
Flat products such as plates, sheets and foils are obtained from aluminum by hot and cold rolling methods.
With the extrusion method, aluminum profiles, rods, pipes, flat bars and wire rods are obtained in various sections.
Aluminum is a metal very suitable for extrusion. Thus, many products in shapes and sizes suitable for their intended use are produced economically without the need for another forming process.
Parts of various sizes and shapes are produced from aluminum by permanent, pressure or sand casting methods.
Aluminum, which is lighter than copper, provides a great advantage in the transmission of electrical energy. For this reason, today energy transmission lines are made of aluminum. Aluminum conductors are produced by a three-stage process consisting of obtaining wire rod by continuous casting, rolling the wire into wire by rolling, and braiding the wires.
Aluminium and Construction
Aluminum is used in large quantities in roofing and facade cladding of buildings, doors and windows, stairs, roof framing, scaffolding and greenhouse construction.
In addition to the durability of aluminum, its decorative appearance becomes immortal with anodized coating. Aluminum with either natural or colored anodized coating or lacquer coating (electrostatic powder or liquid painting); offers architects and engineers a wealth of options in the construction industry. In the construction industry; aluminum extrusion, flat-products and casting products are used in the production of door/window joinery, facade/roof coverings and accessories.
In addition, aluminum is widely used in packaging, vehicles and conductors sectors.
The homogeneous mixture formed by the combination of a metal element with at least one other element (metal, nonmetal) is called alloy. Aluminum, preferably copper, manganese, silicon, magnesium and zinc etc. to gain some properties. It is alloyed by adding elements, that is, it is not used in pure form. For example, while the pure tensile strength of aluminum is 49 MPa, it reaches 700 MPa when alloyed. When classifying aluminum alloys chemically, 4-digit (XXXX) numbers are used as notation. Aluminum alloys are divided into 2 main groups as wrought and cast alloys.
1XXX series 99% < aluminum
2XXX series main component Cu
3XXX series main component Mn
4XXX series main component Si
5XXX series main component Mg
6XXX series main component Mg and Si
7XXX series main component Zn
8XXX series special alloys
classified as. 2XXX, 6XXX, 7XXX, 8XXX series can be heat treated.
Zinc (Zn) gives strength and hardness to the alloy.
Copper (Cu) provides heat treatment, strength and hardness, and reduces corrosion resistance.
Manganese (Mn) increases the yield and tensile strength and provides corrosion resistance.
When Silicon (Si) is used with Magnesium, it provides heat treatability and increases corrosion resistance.
Magnesium (Mg) adds strength and hardness, increases corrosion resistance and weldability.
Aluminum Alloys Used for Extrusion Process
It is a process extrusion suitable for obtaining products with fixed cross-section shapes such as profiles, pipes, bars, flats, including aluminum profiles used in architectural aluminum systems. Alloys used for the production of aluminum profiles with the extrusion process are in the forged alloys group.
6XXX series alloys
Profiles produced for architectural purposes are generally produced from 6XXX alloys by extrusion method. As mentioned above, AA 6XXX series alloys contain magnesium (Mg) and silicon (Si). The ratios of Mg and Si and other impurities (such as Fe, Cu, Mn, Zn) give alloys different properties. For example, 6XXX alloys with an Iron (Fe) content of 0.20% or less are more suitable for obtaining glossy surfaces. In order to obtain a matte surface, high iron ratios should be preferred.
Among the 6XXX series (AlMgSi) alloys, 6060 and 6063 (in EN and new TS notation) and AlMgSi0.5 (DIN and old TS notation) alloys are the most widely used in the architecture – construction industry. Their chemical compositions are generally the same, and they differ in lower and upper limits.
If we compare it with EN AW / AA 6005, 6005A alloys, 6063; It is an alloy that is harder, has stronger mechanical properties, but is more expensive, more difficult to extrude, thus making it difficult or preventing the production of complex geometries.
Profiles made of 6005A alloy can be anodized for protection, but the surface quality makes it difficult to obtain a decorative image.
In terms of plastic forming possibilities, this alloy is not as successful as 6063.
For situations where strength is not the most important criterion, it is the alloy that is suitable for optimal surface quality as a result of surface treatment. It is preferred for decorative priorities such as furniture profiles.
Application areas: There are application areas such as architectural sections, furnishings, frame systems, lighting, step, rail electronic modules, electro motor frames, fasteners, coolers, radiators, pneumatics, irrigation, furniture profiles in window, door and facade systems. 6063 is slightly harder but more difficult to extrude than 6060.
Characteristics: Corrosion resistance is high, weldability is very good, fatigue strength is high, can be cold formed, can be formed in complex geometries.
Compared to 6005, its impact toughness is slightly better, but its susceptibility to decorative anodizing is slightly worse. Other properties are similar to 6005 and 6005A alloys.
If we compare EN AW / AA 6082 alloy with 6063; It is an alloy that is harder, has stronger mechanical properties, but is more expensive, more difficult to extrude, thus making it difficult or preventing the production of complex geometries.
Profiles made of 6082 alloy can be anodized for protection, but the surface quality makes it difficult to obtain a decorative image.
In terms of plastic forming possibilities, this alloy is not as successful as 6063.
Application areas: Heavy structures in railway wagons, truck guardrails, shipbuilding industry, bridges, bicycles, boilers, platforms, flanges, hydraulic parts, pylons, masts, tarpaulin pipes, rivets
Characteristic features: High corrosion resistance, very good weldability, suitable for machine building, cold forming ability in stabilized form after T4 heat treatment is very good, fatigue strength is moderate, not suitable for complex parts.
For profiles with high electrical conductivity and also high hardness, 6101 alloy may be suitable. 1XXX series alloys also have high electrical conductivity, but 6101 is better in terms of cutting processing, and the tensile strength of 6101 alloy is also better than 1XXX series.
It is the most suitable alloy to obtain bright aluminum.
Alloys in this series are not suitable for heat treatment. Corrosion resistance is good. They are preferred due to their high thermal and electrical conductivity as well as being relatively soft and unstable. Its electrical conductivity makes it preferred in the electrical industry, and its high thermal conductivity in the HVACR industry. Another alloy with good electrical conductivity, 6101 alloy is better in terms of cutting – machining and its tensile strength is also better than the 1XXX series.
Application areas: It is used in aircraft industry, general engineering applications, military equipment, parts requiring high hardness and machinability, truck wheels, automotive.
Characteristics: Heat treatment can be applied. Fatigue resistance is high, corrosion property increases with coating.
Areas of application: It is used in exterior applications in the construction industry, corrugated sheets on the roof, marine and offshore applications, food and chemical equipment, advertising industry, road signs, parts requiring anodizing, packaging industry, cooler and heater equipment, pipe and tube construction.
Characteristics: Very good resistance to atmospheric corrosion. Very good weldability. It is very suitable for decorative anodizing. Medium strength alloy.
Different companies prefer different 7XXX alloys when listing alloy alternatives, 7075, 7108, 7005 etc. It can be said that they are all alloys of high hardness and strength. Fatigue resistance is high. Their weldability is good and their hardness does not decrease much in heat affected areas. It is recommended to add glue, rivets and screws. It is recommended to be used with a protector in outdoor environments because its corrosion resistance is not as good as the 6XXX series. It is not as successful in shaping as the 6XXX series.
Application areas: Components requiring high strength in the military and aircraft industry, rubber and plastic molds, ski poles, machine parts requiring high strength, automotive industry, rivets, nuclear applications
Characteristics: Higher hardness can be achieved more easily than 7010.
Heat Treatment of Aluminum Alloys
Different heat treatments can be applied on aluminum alloys. Types of heat treatment in aluminum alloys are:
O: Annealed, F: As Produced, H: Hardened, T: Heat Treated
T1: Cooled after hot forming and left to natural aging.
T2: Cooled after hot forming, cold formed and left to natural aging.
T3: Solution treated, cold formed and left to natural aging.
T4: Solution treated and left to aging naturally.
T5: Cooled and artificially aged after hot forming.
T6: Solution treated and artificially aged.
T7: Solution treated and over-aged.
T8: Solution treated, cold formed and artificially aged.
T9: Solution treated, artificially aged and cold formed.
T10: Chilled after hot forming, cold formed and artificially aged.
The applied heat treatment is used to define the material by writing Tx (T1, T2, etc.) symbols next to the alloy number.
By keeping the aluminum alloy at room temperature, the hardening of the alloy elements in the solid solution by separating from the solution and precipitating, and the increase in the hardness of the material is called “natural aging”.
After the extrusion process of aluminum profiles used in aluminum window and facade systems, the profiles are kept in thermal (heat treatment) furnaces at 180C for 5 hours. This process is called “artificial aging”. In this way, hardness values that are too high to be obtained by natural aging can be achieved.
Related standard: TS EN 515 (Aluminum and aluminum alloys – Temper designation of formable products)
Conversion from Aluminum to Profile (Extrusion)
Raw aluminum profiles are formed by shaping aluminum billet (cylindrical aluminum alloy raw material) with aluminum extrusion method, cooling it on the bench, cutting it in standard or special lengths and achieving the desired hardness value by artificial aging. While raw profiles are produced in 6 meters as standard, they can be ordered in different lengths upon agreement with the manufacturer. Some computer programs help to minimize wastage by optimizing cut lengths. This means less waste for the applicator. With the installation of a thermal insulation barrier, plastic profiles called thermal insulation barrier are applied and compressed between 2 aluminum profiles. Thus, a heat-insulated aluminum profile is formed.
Aluminum profiles that have been thermaled but not subjected to any surface treatment are called raw profiles. Due to the nature of aluminum, there is an oxide layer of 1-2 microns on the raw profiles. This layer also protects the aluminum to some extent against oxidation. However, these raw aluminum profiles are subjected to one of the surface treatments in order to be aesthetically pleasing to the eye and to protect them from corrosion. These surface treatments; It can be anodized, electrostatic powder coating or wood pattern coating.
With the extrusion method, aluminum can produce a geometry on the paper plane (2 axes) in very precise dimensions in the desired length. With this method, aluminum profiles can be produced for many sectors such as architecture, automotive, ship, aircraft, electricity, machinery, chemistry and food.
Aluminum Extrusion Press
Aluminum extrusion process is carried out with aluminum extrusion presses. As the tonnage of the presses increases, the billet (pipe) diameters also increase, and thus the maximum die sizes that can be printed also increase, allowing more figured molds to be made.
Aluminum Extrusion Process
The steel mold designed in accordance with the desired aluminum profile shape is heated and placed in the extrusion press.
Again preheated, cylindrical aluminum extrusion is driven into the press sleeve.
The extruder compresses the billet towards the die by means of a punch.
The aluminum billet, which takes the shape of the mold, is now called an aluminum profile.
The profile is cooled and subjected to stretching and cutting to the desired length.
Artificial aging (thermal) process is applied for architectural aluminum profiles to obtain the desired mechanical properties.
The cross section of the aluminum profile obtained by the extrusion method is constant throughout the profile. In order to obtain the desired cross-section profile, steel aluminum extrusion molds are manufactured and stored for repeated use. In an aluminum extrusion factory that manufactures aluminum joinery profiles, there should be at least as many steel extrusion molds as it produces hundreds of profiles, considering the different wall thicknesses, different depth and width variations of the casing, middle rail, wing, lath profiles.
Extrusion presses are classified according to the pressure they apply. Large presses are more suitable for drawing large profiles and small presses are more suitable for drawing small profiles. In theory, small shaped profiles can be drawn by increasing the number of figures (the number of profiles coming out of a mold) in large presses, but in practice this is not always possible due to the difficulty of controlling the shape tolerances.
TS-EN Standards Related to Aluminum Alloys
TS EN 12020-1 Aluminum and aluminum alloys – precision profiles manufactured by extrusion from EN AW – 6060 and EN AW – 6063 alloys – part 1: Technical inspection and delivery conditions
TS EN 12020-2 Aluminum and aluminum alloys – precision profiles manufactured by extrusion from EN AW – 6060 and EN AW – 6063 alloys – part 2: Dimension and shape tolerances
TS EN 13981-1 Aluminum and aluminum alloys – Products for structural rail applications – Technical requirements for inspection and delivery – Part 1: Extruded products
TS EN 755-1 Aluminum and aluminum alloys – Extruded wire rod/bar, pipe and profiles – Part 1: Technical inspection and delivery conditions
TS EN 755-2 Aluminum and aluminum alloys – Extruded wire rod/bar, pipe and profiles – Part 2: Mechanical properties
TS EN 755-3 Aluminum and aluminum alloys – Extruded wire rod/bar, tube and profiles – Part 3: Round bars, tolerances on size and shape
TS EN 755-4 Aluminum and aluminum alloys – Extruded wire rod/bar, pipe and profiles – Part 4: Square bars, tolerances on size and shape
TS EN 755-5 Aluminum and aluminum alloys – Extruded wire rod/bar, pipe and profiles – Part 5: Rectangular cross-section bars, tolerances on size and shape
TS EN 755-6 Aluminum and aluminum alloys – Extruded wire rod/rod, pipe and profiles – Part 6: Hexagonal bars, tolerances on size and shape
TS EN 755-7 Aluminum and aluminum alloys – Extruded wire rod/bar, pipe and profiles – Part 7: Seamless pipes, tolerances on size and shape
TS EN 755-8 Aluminum and aluminum alloys – Extruded wire rod/bar, pipe and profiles – Part 8: Porthole pipes, tolerances on size and shape
TS EN 755-9 Aluminum and aluminum alloys – Extruded wire rod/bar, pipe and profiles – Part 9: Profiles, tolerances on size and shape
TS EN 13957 Aluminum and aluminum alloys – Extruded round, coiled pipe – For general applications – Specifications
Aluminum Profile Surface Treatment Types
Aluminum profiles can be produced in a wide variety of shapes, as well as in a wide variety of surface appearances. Aluminum surface treatments not only give the product the desired aesthetic appearance, but also help to increase the resistance of the profiles against corrosion and wear. In general, we can talk about 3 different surface treatments.
Anodizing, Anodic Oxidation, Anodization
Electrostatic Powder Coating
Wood Look, Wood Pattern
Anodizing, Anodic Oxidation, Anodization
The type of electrochemical surface treatment, which can give aluminum brown and black tones, even copper and gold colors, without spoiling its metallic appearance, is called “anodizing”. The pretreatments applied before the anodizing process determine the texture of the metallic appearance and whether it is matte or glossy.
From the production side, first of all, it should be sought that the anodized aluminum profiles are produced by manufacturers with Qualanod quality certificate.
Anodizing pretreatments are mechanical and chemical pretreatments, respectively, and vary according to the desired surface appearance. If a matte appearance is desired, satination mechanical pre-treatment is applied. According to this method, extrusion lines are eliminated with stainless steel brushes and a unique satin surface texture formed by the brushes dominates the profile. If a bright appearance is desired, polishing pretreatment is applied. Accordingly, the profiles are polished with a liquid or solid polish.
In DIN 17611, standard nomenclatures were used for anodizing pretreatments and color selections. Accordingly, when we say E6EV1 to indicate the color selection in E0, E1, E2, E3, E4, E5 and E6 preprocesses EV1, EV2, EV3 and EV6, it means that EV1 (Natural Color) is desired after E6 (Chemical Matting) preprocessing. C0, C31, C32, C33, C34 and C35 are used in the naming of EURAS (European Association of Anodizing Companies).
E0 degreasing and oxidation
E3 mechanical polishing
E4 sanding + brushing
E5 sanding + polishing
E6 chemical matting
EV1 neutral color
EV3 golden yellow
EURAS color notations
C0 natural anodized color
C31 very light bronze color
C32 light bronze
C34 dark bronze
Accordingly, anodized surface treatment E0 EV1 can be used as a basis to protect aluminum from corrosion. Apart from the decorative appearance, it may be requested to be anodized on the aluminum surfaces where the glass will be transferred to the aluminum on the curtain walls.
The anodizing process is an electrochemical process. Accordingly, the aluminum profile is immersed in an acidic electrolyte as the anode. Direct current is passed between the cathodes in the bath and the profiles with anode behavior, and with this method, an oxide layer of 5-30 microns, based on aluminum oxide, is formed on the surface of the aluminum profile.
How many microns should the anodized layer be?
The chart below can be used in this regard. It is seen that the 25 µm (micron, micrometer) thick anodized coating is eroded by 0.07 to 0.50 µm/year depending on the weather conditions.
The amount of wear of the anodized layer (micro meters – years)
In summary, the durability of the 25 µm thick anodized layer is 40 years, and 30 years in bad weather conditions.
According to DIN 17611, 20 micrometer anodized layer is required for anodized profiles used for architectural purposes. According to the British standard (BS), it is required to be 25 micrometers.
Electrostatic Powder Coating
The surface of aluminum profiles can be coated with powder paint and the desired color appearance can be obtained. Standard RAL colours, color mixes, special colours, plus velvet, rough etc. surface effects and even surface properties such as self-cleaning can be achieved with powder coating. Having so many varieties is an advantage when compared to anodized.
From the production side, first of all, it should be sought that the powder coated aluminum profiles are produced by manufacturers with Qualicoat quality certificate. There are over 500 products and over 400 licensed paint coating facilities.
What is powder coating?
It is also called electrostatic powder coating, powder coating, powder coating.
Powder coating is a type of coating applied as a freely sprayed dry powder. The coating is applied electrostatically and then cured under heat to allow it to flow to form a thin layer.
There are two main categories of powder coatings: Thermoset and thermoplastic polymers. The most common polymers used are polyester, polyurethane, polyester-epoxy, plain epoxy and acrylics. The components of the powder coating process may vary slightly from manufacturer to manufacturer.
Powder coating is used to create a hard, continuous coating on the aluminum surface that will protect the metal from corrosion and provide an attractive appearance that lasts when exposed to various weather conditions. Powder coating is mainly used for household appliances, aluminum extrusion products (window profiles, other architectural profiles, etc.), automotive and industrial applications.
Powder Coating Properties
Because powder coating does not have a liquid carrier, it can produce thicker coatings than conventional liquid coatings. The coating process emits few volatile organic compounds VOCs. Several powder colors can be cured together, allowing for mixing of colors and special effects in a single layer. Thick coatings are relatively easy to apply, allowing for smooth, non-woven coatings, thin coatings are not.
One of the most important advantages of powder coating is that the excess powder that cannot be attached to the product during the powder coating process can be recycled.
Many noticeable advantages (hardness, gloss, etc.) of powder coating over liquid coating (except PVDF) are actually a characteristic of polymers.
Powder coating process
Preparation process and pretreatment
Cleaning of aluminum before powder coating is done by various chemical and mechanical methods. The choice of method depends on the material and size of the part to be powder coated, as well as the performance requirements of the finished product.
The pretreatment process both cleans the metal and increases the adhesion of the powder to the metal. Chemical pretreatments usually take place in multiple stages and consist of steps such as degreasing, etching, de-casting, various rinsing and chromating.
Recently, processes have been developed that prevent the use of chromates. Titanium and zirconium chemicals and silanes also show similar performance against corrosion and increasing dust adhesion.
Another method of preparing the surface before coating is known as abrasive blasting or blasting.
Powder coating application process
The most common way to apply powder coating to metal objects is to spray the powder using an electrostatic gun. The gun imparts a positive electrical charge to the powder. The powder is sprayed by accelerating towards the part to be painted, which is then grounded by mechanical or compressed air. Then, the object covered with powder is heated and the powder is melted and spread on the painted part in the form of a uniform film layer.
When a thermoset powder is exposed to a high temperature, it melts, flows and then chemically reacts to form a higher molecular weight polymer in a network structure.
This curing process can take place at a certain temperature for a certain period of time. Normally powders cure at 200 °C (390 °F) for 10 minutes.
Applications for powder coated aluminum
Powder coated aluminum is a building material that can find applications in a number of construction projects. Powder coating on aluminum helps to increase the corrosion resistance ability of the metal. This makes the material ideal for outdoor use.
The architectural powder coating offers a wide range of appearances, starting with white, in numerous RAL colors and other special colors, with desired effects.
Industrial uses is one of the largest markets for powder coatings. For example, the automotive industry is experiencing a dynamic growth in this regard.
The choice of powder coating depends on the application and is not simply a personal choice. Powder coating does not contain solvents and the coating process does not create hazardous waste. The recyclability of excess powders that do not adhere to metal during the process makes powder coating an environmentally friendly method.
Anodizing & Electrostatic Powder Coating Comparison
In order for the aluminum profiles to have the desired surface color and properties, one of the processes of anodizing and electrostatic powder painting is applied. As a result of the anodized surface treatment, the metallic surface of the aluminum can still be noticed, while the surface gains a more plastic appearance as a result of powder coating.
When we compare these 2 surface treatment options;
Advantages of Anodizing:
It is easy to maintain, it can be wiped with water and regained its old appearance.
It does not peel or flake.
Since it is a transparent coloring, the natural metallic surface of aluminum is noticeable.
It is resistant to the sun, does not fade. However, organic coatings are affected by ultraviolet rays.
You’ll see consistent color no matter which angle they’re viewed from.
There is no problem of peeling off like paint in silicone facade applications where we glue the glass to aluminum with silicone.
There is no such thing as paint peeling, no peeling. Because anodized coating is part of the surface.
It is more resistant to physical contact and abrasive cleaning materials. In this respect, it is easier to use in places where it can be accessed and where contact may occur.
Disadvantages of Anodized:
It is weak against acidic pollutants in city life.
Color types are very few compared to powder painting.
It is more difficult to keep the same color, especially when intermediate dark colors are desired.
Only matte and glossy surfaces can be achieved
Since only aluminum can be anodized, it is difficult to match with other materials on the facade.
It is difficult to remove scratches etc. that occur afterwards.
Electrostatic powder coating advantages:
Color retention is not a problem, regardless of whether they are produced in the same batch.
Color variations are many.
Resistant to acidic and alkaline chemical cleaners.
The process does not pollute the air.
Powder coatings emit zero or almost zero volatile organic compounds.
Electrostatic powder coating disadvantages:
If the pretreatments are not done correctly, the effect we call “Filiform Corrosion” is seen.
Orangeness may be seen.
Chalking can be seen.
Silicone is not suitable for attaching glass to the facade with silicone.
Wood Look, Wood Pattern
Another advantage of aluminum is that in aluminum joinery made with heat-insulated profiles, the aluminum parts on the inside and outside sides of the space can be of different colors and can even be subjected to different surface treatments. In this way, for example, while a wooden appearance is provided on the surface facing the interior, the color of the exterior architecture of the building (for example, the natural anodized color) can be adhered to on the surface facing the exterior. This is another advantage of aluminum joinery.
Wood-looking aluminum is obtained by coating a wood-patterned film on the surface of aluminum profiles and transferring the pattern on this film to the aluminum surface by baking. Wood pattern coating process consists of 2 stages:
First of all, aluminum profiles are subjected to electrostatic powder painting process. In this process, a primer paint is applied in brown tones that determine the tone (light or dark) of the wood pattern (oak, pine, etc.).
In the second stage, the top of the profiles is covered with wooden transfer paper and vacuumed from both ends of the profile and baked. In the baking process, the pattern on the paper is transferred to the aluminum profile surface and the films are removed at the end of the process.
Since it is possible to obtain surfaces in different tones with primer paint and in different patterns with transfer paper, it is possible to obtain different types of surfaces as “primer tone” x “transfer paper pattern”.
It is recommended that wood patterned profiles have the Qualideco certificate.
Installing Heat Barrier on Aluminum Profiles
In order to provide thermal insulation of aluminum windows, plastic profiles are placed between the inner and outer shells of the aluminum profiles and the formation of thermal bridges is prevented. So how are these thermal insulation barriers mounted on aluminum profiles? How to ensure that the slip values keep the values specified by the standards?
Installation of thermal insulation barrier on aluminum profiles takes place in 4 stages:
Threading (knurling) aluminum profiles
In aluminum profiles, the process of threading the channels where the thermal insulation barriers will enter is done in order to strengthen the shear strength. If this process is not done correctly, the heat barriers will not be squeezed into the aluminum profile channels sufficiently and will cause the profiles not to give the desired values in the stiffness test (shear stress test). Threading (knurling) machines work with the principle of executing 2 hardened special discs on an aluminum profile. In a suitable threading process, sharp teeth should be formed on aluminum profiles and the spaces between these teeth should have 3 times more space than the teeth. Thus, the optimum adhesion between the two materials is achieved.
Insertion of thermal barriers into barrier slots in aluminum profiles (assembly, insertion)
Polyamide insulation barrier manufacturers ship the profiles not only as longitudinal profiles, but also as coils upon request. There are machines developed to facilitate the application of insulation profiles to aluminum profiles, whether in length or as a coil.
Compressing heat barriers to aluminum profiles (curling, crimping, rolling)
The compression process (rolling / crimping) of the thermal insulation profiles applied to the aluminum profile channels is done with the help of machines designed for this job. For a good compaction process, the most suitable settings for the dimensions of the profiles are entered into the machine automatically or manually. Pressure adjustments must be made carefully so that rotations and breaks do not occur during the compression process. The cause of problems such as rotation, breakage or poor compression may be due to thermal insulation barriers, as well as the pressure created by the discs that are not adjusted correctly according to the profile.
Rigidity – Shear strength test (rigidity test)
Whether the heat barriers hold well to aluminum profiles is the stage we test. Thanks to the shear strength test, the correct assembly of the composite profiles is tested. All of these stages are carried out with machines specially designed for the sector.
Aluminum Profile Manufacturers
There are many companies producing aluminum profiles in Turkey. Aluminum profile manufacturers (aluminum profile factories), most of which are in Istanbul, Izmit, Tekirdag and its surroundings, are located all over the country such as Adana, Izmir, Konya, Zonguldak, Kayseri. Global, large system manufacturers, on the other hand, work together with aluminum profile factories in Turkey and choose to have their profiles produced locally in Turkey. Aluminum extrusion (aluminum profile) companies producing in Turkey produce in a quality that meets the needs of global companies. Many of these aluminum profile manufacturers in Turkey also have their own aluminum window, door and facade systems. In other words, they work as both aluminum profile manufacturer and architectural aluminum window, door, facade system house, architectural system designer and manufacturer. For this, these aluminum companies either have their own architectural product development offices or they get design support from outside.
You can reach Sistem House companies and Extrusion companies operating in Turkey from the relevant links.