Knowledge Base In Aluminium
Aluminium is light with a density one third of that of steel.
Aluminium is strong with a tensile strength of 70 to 700MPa depending on the alloy and manufacturing process. Extrusions of the right alloy and design are as strong as structural steel.
The Young's modulus for aluminium is a third that of steel (E=70,000 Mpa). this means that the moment of inertia has to be three times as great for an aluminium extrusion to achieve the same deflection as a steel profile.
Aluminium has a good formability, a characteristic that is fully utilized in extruding. Aluminium can also be cast, drawn and milled.
Aluminium is very easy to machine. Ordinary machining equipment can be used such as saws and drills. Aluminium is also suitable for forming in both the hot and cold condition.
Aluminium can be joined using all the normal methods available such as welding, soldering, adhesive bonding and riveting.
- Corrosion resistance
A thin layer of oxide is formed in contact with air, which provides very good protection against corrosion, even in corrosive environments. This layer can be further strengthened by surface treatment such as anodising or powder coating.
The thermal and electrical conductivities are very good, even when compared to copper. Furthermore, an aluminium conductor weighs half that of an equivalent copper conductor.
- Linear expansion
Aluminium has a relatively high coefficient of linear expansion compared to other metals. This should be taken into account at the design stage to compensate for differences in expansion.
Aluminium is not poisonous and is therefore highly suitable for the preparation and storage of food.
Aluminium is a good reflector of both light and heat
What is an alloy?
Aluminium alloys are alloys in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable. About 85% of aluminium is used for wrought products, for example rolled plate, foils and extrusions. Cast aluminium alloys yield cost-effective products due to the low melting point, although they generally have lower tensile strengths than wrought alloys. The most important cast aluminium alloy system is Al–Si, where the high levels of silicon (4.0–13%) contribute to give good casting characteristics. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required.
Alloys composed mostly of aluminium have been very important in aerospace manufacturing since the introduction of metal-skinned aircraft. Aluminium-magnesium alloys are both lighter than other aluminium alloys and much less flammable than alloys that contain a very high percentage of magnesium.
Aluminium alloy surfaces will develop a white, protective layer of aluminium oxide if left unprotected by anodizing and/or correct painting procedures. In a wet environment, galvanic corrosion can occur when an aluminium alloy is placed in electrical contact with other metals with more positive corrosion potentials than aluminium, and an electrolyte is present that allows ion exchange. Referred to as dissimilar-metal corrosion, this process can occur as exfoliation or as intergranular corrosion. Aluminium alloys can be improperly heat treated. This causes internal element separation, and the metal then corrodes from the inside out. Aluminium alloys with a wide range of properties are used in engineering structures. Alloy systems are classified by a number system (ANSI) or by names indicating their main alloying constituents (DIN and ISO).
General alloy natural properties
The 6000 series has good extrudability and can be solution heat treated at the extrusion temperature. Furthermore, these alloys have medium to high strength, are easy to weld and offer good resistance to corrosion, even in marine environments. The bulk of the extruded material for load bearing constructions is made from these qualities. They are used for load bearing constructions both on land and at sea.
Choose the right alloy
EN AW-6060 - ISO: AIMgSi Composition: Al 0,5Mg 0,5Si Fe
Applications: Architectural sections for windows, doors, curtain walls. Interior fitting, frame system, lighting, ladders, railings,fences. Heat sink sections, electronic modules, electro motor housings. Flexible assembly systems, special machinery elements. Truck and trailer flooring, pneumatic installation, railway, inside applications. Irrigation, heating and cooling pipes. Furniture, office equipment.
Characteristic properties: Very good corrosion resistance. Very good weldability. Good cold formability especially in temper T4. Medium strength heat treatable alloy with a strength slightly lower than 6005A. Medium fatigue strength. Commonly used alloy for very complex cross sections. Standard decorative anodizing quality
Product Forms: Bar, Profile section shape, Rod, Slugs impacts, Tube, Wire.
- EN AW - 6063 - ISO: Composition: AlMg0,7Si Al 0,7Mg 0,4Si
Applications: Architectural sections for windows, doors, curtain walls. Interior fittings, frame systems, lighting, ladders, railings etc. Heat sink sections, electronic modules, electro motor housings. Flexible assembly systems, special machinery elements; Truck and trailer flooring, pneumatic installation, railway, inside applications. Irrigation pipes. Furniture, office equipment. Radiator and other heat exchanger applications.
Characteristic properties: Very good corrosion resistance. Very good weldability. Medium strength heat treatable alloy slightly lower than 6005A. Medium fatigue strength. Good cold formability especially in temper T4. Suitable for very complex cross sections. Standard decorative anodizing quality.
Product Forms: Bar, Profile section shape, Rod, Slugs impacts, Sheet, Tube, Wire.
- EN AW-6005A- ISO: AlSiMg(A) : Al 0,6Mg 0,7Si Mn Cr
Applications: Railway and bus profile structures with complex sections (integral structures). Structural engineering, pylons, platforms, pipeline. Applications in the electrical and mechanical precision industries. Extruded sections for various purposes requiring strength greater than 6060 and 6063. Masts for sailing boats. Furniture.
Characteristic properties: Very good corrosion resistance. Very good weldability. Medium high strength heat treatable extrusion alloy, strength slightly higher than 6060 and 6063. High fatigue strength. Better extrusion characteristics than 6082 and 6061 for complex cross sections.
Product Forms: Bar, Profile section shape, Tube.
- EN AW-6082 - ISO: AlSi1MgMn Composition: Al 0,9Mg 1,0Si 0,7Mn
Applications: Heavy duty structures in rail coaches, truck frames, ship building, offshore, bridges, military bridges, bicycles, boiler making. Machinery: platforms, flanges, hydraulic systems, mining equipment, pylons and towers, motorboats. Nuclear technology. Masts and beams for ship building (especially for sweet water). Tubes for scaffolding, framework for tents and halls, piping, tubing Screw machine products. Rivets.
Characteristic properties: Very good corrosion resistance. Very good weldability (lowered strength values in the zone of welding). Good machinability. Good cold formability in T4 temper after a stabilizing heat treatment. Heat treatable medium high strength construction. Alloy with a strength somewhat higher than 6061. Medium high fatigue strength. Not suitable for complex sections.
Product Forms: Bar, Forging, Profile section shape, Plate, Slugs impacts, Sheet, Tube, Wire.