Aluminium

 ALUMINIUM

Aluminium is a silvery-white metal, which is widely used in building because of its inherent properties of lightness and corrosion resistance. It's the most widespread metal on earth, making up more than 8% of the earth's core mass. It's also the third most common chemical element on our planet after oxygen and silicon.

PROPERTIES OF ALUMINIUM

The different properties of aluminium are discussed below:

❖ Durability: Aluminium building products are made from alloys, which are weather-proof, corrosion-resistant and immune to the harmful effects of UV rays, ensuring optimal performance over a very long serviceable lifetime.

❖ Design flexibility: The extrusion process offers an almost infinite range of forms and sections, allowing designers to integrate numerous functions into one profile. Rolled products may be manufactured flat, curved, shaped into cassettes, or sandwiched with other materials. In addition, aluminium can be sawn, drilled, riveted, screwed, bent, welded and soldered in the workshop or on the building site.

❖ Hundreds of surface finishes: Aluminium can be anodized or painted in any colour, to any optical effect, using any number of surface touches, in order to meet a designer's decorative needs. Such processes also serve to enhance the material's durability and corrosion resistance, as well as providing an easy-to-clean surface.

❖ High reflectivity: This characteristic feature makes aluminium a very efficient material for light management. Aluminium solar collectors can be installed to lower energy consumption for artificial lighting and heating in winter, while aluminium shading devices can be used to reduce the need for air conditioning in summer.

❖ Fire safety: Aluminium does not burn and is therefore classed as a non- combustible construction material. Aluminium alloys will nevertheless melt at around 650°C, but without releasing harmful gases. Industrial roofs and external walls are increasingly made of thin aluminium cladding panels, intended to melt during a major fire, allowing heat and smoke to escape and thereby minimizing damage.

❖ Optimal security: Where high security is required, specially designed, strengthened aluminium frames can be used. While the glass for such applications may well be heavy, the overall weight of the structure remains manageable thanks to the light weight of the aluminium frame.

ALUMINIUM ALLOYS

Aluminum is commonly alloyed with copper silicon, magnesium, or zinc to improve its mechanical properties. Some aluminum alloys also contain one or more of the metals manganese, lead, nickel, chromium, titanium, and beryllium. A large part of the aluminum production is utilized in making light, stiff, corrosion-resistant alloys with these metals. Aluminum alloys may be classed as the cast alloys, which are shaped by casting and wrought alloys, which are worked into different shapes by mechanical operations. Cast alloys are generally binary alloys containing copper or silicon, and sometimes magnesium. Wrought alloys contain copper, magnesium, silicon, and manganese that form precipitation hardening alloys with aluminum. Following are some of the aluminum alloys.

❖ Magnesium is an alloy of aluminum and magnesium (6 per cent). It has got very good mechanical properties and is a little lighter than pure aluminum. It is easy to work, exceptionally strong, and ductile and is widely used as deoxidizers in copper smelting operations.

❖ Y-alloy: It contains 4% copper, 20% nickel and 1.5% magnesium. Toughness and hardness are achieved by heating it to 500° C for six hours and then cooling it down in boiled water. Its relative density is 2.80 and resists corrosion better than duralumin. Y-alloy has good thermal conductivity and can sustain high temperature. It is used for making pistons of I.C. engines, cylinder head, connecting rod and propeller blades.

❖ Aluminium Bronze contains less than 11% of aluminium and is highly ductile when aluminium is less than 7.3%. As the aluminium increases, ductility decreases and at 12% the alloy is very brittle. Bronzes containing less than 7.3 per cent aluminium are highly resistant to torsional stress, readily rolled, forged, cold drawn, exhibit toughness under impact and resistance to alternate bending stress.

❖ Light Alloy contains 3% copper and 12% zinc. It is used for castings such as crank and gear housings.

❖ Aluminium-Copper Alloy contains copper up to 4%. Less liable to burning the alloy produces light castings that are stronger and tougher than that made from aluminium. It is mainly used in automobile industry for casting.

❖ Aluminium-Zince Alloy contains zinc up to 15% and is used for light casting which can be easily machined or forged into desired form. These are very sensitive to high temperatures in melting and in solid form exhibit low strength and brittleness when heated above 50° C. Alloys containing 15 to 25% zinc are harder, stronger, but less ductile and more difficult to roll or draw.

❖ Aluminium-Silicon Alloy: Aluminium alloys containing 5 to 15% silicon are important because of their excellent casting qualities and fluidity. It is free from hot-shortness and permits the pouring of thin intricate sections. They also have high resistance to corrosion and are good conductors of heat having low thermal expansion .

MARKET FORMS OF ALUMINIUM

Common products and applications of aluminium are stated as follows:

1. Fenestration (Windows and Openings) Casing Profiles

The major usage of aluminium can be observed in building fenestration casings like door and window frame profiles. These are easy to extrude sections and executed on-site and are readily available as per requirement. They are light in weight, yet strong. These are rigid in composition but flexible enough to use for design executions. They are available in various finishes like anodised colours, raw mill finishes with different hardness according to the alloy used in the extrusion process.

2. Facade Cladding (Aluminium Composite Panels- ACP)

Exterior facades are prone to weather hazards and building designs are now preferably shifted towards added aesthetics. Aluminium cladding is the most used type of cladding for building exteriors for economical, functional and aesthetical reasons. Aluminium composite Panels (A.C.P.) are widely used because of variety of colours and ease of installation with low maintenance.

3. Structural Glazing and Curtain Walls

These glazings provide a smooth look to the design with extremely low heat-gain coefficient through glazing solutions. Curtain wall systems are typically designed with aluminium framing members. These frames are infilled with glass for pleasing finishes and better daylighting effect.

4. Light Weight Partitions

Aluminium section profiles can create partitions that are easy to alter and are functionally considerable. They are better options for designing partitions at low cost and better aesthetics. They can be customized on-site and are readily available in different section profiles for different infill options like glazing, net or solid panels of acrylic.

5. Architectural Hardware and Shop Fittings

Architectural fittings like handles, knobs, clamps, holding fixtures are easy to produce in aluminium and are light weighted option. It is a cost-effective solution when compared to wood and steel with similar strength and lesser strength to weight ratio. Thus they can be produced in larger quantities in similar weight productions.

6. Aluminum Shutters for Cladding

Aluminium shutters can be considered as a viable long term investment as they don't require frequent servicing and does not require replacing regularly. These are durable and are fairly resistant to possible impacts. These can be sturdy, strong and rigid structures with variable available colour option to choose with your choice of colour scheme.

7. Aluminium Long Span Roof System

Use of aluminium in large-span structures is useful and effective. These large- span structures are light-weight when constructed in aluminium composition. Generally, Halls and auditoriums that require clear spaces of large spans can opt for aluminium bracing and frames for structural form. Complex structures of large spans can be divided into simpler units in aluminium sections for construction purposes.

8. Aluminium in Electrical Transmission Towers

Electrical transmission Structures that are constructed at inaccessible places where transportation is tough, simpler units of aluminium are transported through air and assembled. Aluminium is used for reduced weight construction in such construction processes.

9. Aluminium Ladders, Scaffoldings and Mezzanine Frames

Aluminium ladders, scaffoldings are stable and secure options when produced in adequate diameters. It is easy to mantle and dismantle. These are light-weight than all other available options. Aluminium is a viable option here than wood or steel because it needs less maintenance.

USES OF ALUMINIUM

❖ Aluminum is used in external facades, roofs and walls, in windows and doors, in staircases, railings, shelves, and other several applications.

❖ Aluminium is widely used in the packaging industry for the production of coils, cans, foils, and other wrapping materials.

❖ Aluminium bronze is used for pump lines, tubes, springs, screws, rivets, ornamental works, marine engineering castings, motor boat shafting, musical instruments, and as a substitute of mild steel to resist corrosion, grill works, etc.

❖ It is also a component of many commonly used items such as utensils and watches.

❖ It is used in the transport industry for the production of cycles, spacecraft, car bodies, aircraft and marine parts.

❖ Aluminium also finds applications in the production of paints, reflective surfaces, and wires.