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In the first Part of our Story of Aluminum, we learnt how aluminum and its alloys are sourced and produced. Now we will turn to its uses and why?

Aluminium began to see increased usage in engineering and construction at the turn of the 20th Century and, in the two World Wars, where the metal was developed extensively as a strategic material. Global production grew from about 7,000听metric听tons in the early 1900鈥檚 to almost 3,000,000听metric听tons by the mid 1950鈥檚. Over time, the introduction of methods for the mass production of aluminium has led to extensive use of this metal in industry and in our everyday life

In the second half of the 20th century, aluminium gained usage in transportation and packaging as the use of the metal in recycling exploded, backed by serious environmental concerns. Global production has since continued to rise, reaching 69,000,000听metric听tons by 2022. Now, production of aluminum and its alloys exceeds those of all other the other non-ferrous metals combined.

Aluminum and its alloys have important and special properties, not the least of which are:听

• their toughness at low temperatures

• their light weight,听

• their corrosion resistance听

• their electrical conductivity.

• their high thermal conductivity and

• their formability

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Their Low Temperature Toughness

The good low temperature ductility properties (referred to as cryogenic properties) of aluminum make certain alloys suitable for the storage and transport of liquefied natural gas (LNG) at a temperature of minus 161掳C, when natural gas becomes a liquid. Liquefied Natural Gas (LNG) is a large source of energy along the chain in the transition to a greener world. However, it is also a hazardous substance that requires careful handling and storage.听 Aluminum alloys are widely used in the construction of the aforementioned LNG storage tanks, both land and ship borne, due to their excellent corrosion resistance, relatively high strength, and their low temperature properties.听

An LNG ship is designed to transport LNG from a liquefaction plant to a receiving station. The storage tanks of LNG ships are a special structure, independent of the hull. Figure 1听shows a typical LNG ship illustrating Aluminum alloy storage domes. The spherical design is to reduce stress concentrations and makes the resistance to stress uniform throughout the surface.

Figure 1 LNG Ship with On-Board Spherical Storage Tanks

Among the most commonly used aluminum alloys for this purpose are 5083 and 5454.These alloys will be discussed in a later note on the 鈥淪tory of Aluminum鈥�

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Their Light Weight and Corrosion Resistance

Aluminum alloys are an excellent material for luggage, as shown in Figure 2. The alloy is听lightweight, weather-resistant and is generally more durable than polycarbonate luggage. Aluminum is strong enough to withstand being carted around airports, thrown into overhead bins or being tossed into the trunk many hundreds of times. It is also easy to clean and these advantages have made it a popular choice with business travelers.

Figure 2 A typical lightweight Roll On/Roll Off Suitcase that can be made in Aluminum Alloy

When aluminum听 alloys are used for transportation, less energy is required for moving both people and/or merchandise. The energy and/or weight savings in many instances can justify the higher cost of aluminum alloys relative to those of steel.听

An example of this is transportation on our roads by truck. Using aluminum alloys, the lighter vehicles can travel on otherwise weight restricted roads, are able to carry more cargo and, as a consequence can gain more revenue from their activities.听

An important use of aluminum alloys is in the fabrication of high-speed Search and Rescue Vessels (SAR鈥檚) for the Canadian Coast Guard. These vessels are fast, with speeds up to 25 knots. Since they do not suffer from the same corrosion problems as steel vessels in salt water environments they may not need to be drydocked as regularly for maintenance on the hulls.

Other significant transportation areas where weight is critical include aircraft , aerospace launch vehicles/fuel tanks, trains for the transport of goods, fire trucks and catamaran fast ferries powered by water jets where, similar to aircraft, the weight has to be reduced to a minimum.听

Additive to the light weight of Aluminum alloys is the great corrosion resistance which makes the material suitable for pipes and tanks in specialty chemical plants such as the production of hydrogen peroxide.

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Their Electrical and Thermal Conductivity

The high electrical conductivity of aluminum makes it ideal for electrical delivery systems. Many听

overhead transmission lines that carry power from the power-generating facilities to cities or plants are made from aluminum wires with a steel core for strength.听

The high thermal conductivity of aluminum is used for the extraction of heat. For this application it is commonly used in the form of an extrusion having a shape with many fins to facilitate the transfer of heat to the atmosphere or other cooling medium.听

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Their Formability

The formability of certain alloys allows for the making of beverage cans. Globally,听around 370 billion听aluminum cans are produced each year to hold pop, beer and many other beverages. That鈥檚 about 45 aluminum cans per person per year. This is an incredible number.听

Here in the America鈥檚, we produce about annually about 120 billion of these cans, about one third of the world鈥檚 needs. Another staggering number.

When we turn to the joining, the welding of certain aluminum alloys can be difficult depending on the alloy itself, and there are a number of pointers we need to discuss as we progress in our story. The alloys can be split into two types, those that derive their properties from heat treatment and those which do not.

In future articles we will discuss these alloy differences and then, turn to their weldability.

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