Uses of aluminium:
- Aircrafts:
  - Airplanes use aluminium alloys and carbon fibres for stronger, lighter airframes.
  - Aluminium is used in aircrafts because it is strong and has a low density.
  - Aluminium has low density as it is not part of the transition metals.
    - Transition metals have high densities and are thus too heavy to be made into aircraft.
  - Since weight savings are extremely important on an aircraft, aluminium is used.
- Food containers:
  - Aluminium is used in making food containers because it does not corrode, while iron rusts.
  - For this reason, aluminium is also used for food packaging.
  - Aluminium containers can be used to bake food in the oven as well because aluminium has a high melting temperature.
  - Hence, aluminium is used in cookware because it is light, strong, heat resistant as well as a good conductor of heat.
- Overhead electrical cables:
  - Aluminium is used in the manufacture of overhead electrical cables as well because of its low density and relatively good electrical conductivity.

Uses of copper:
- Cooking utensils:
  - Copper is used in making cooking utensils, such as pots and pans due to its high thermal conductivity.
  - Copper has the second highest heat conductivity among metals.
  - Additionally, copper is very unreactive towards water, oxygen, steam, and acids, making it suitable for cookware.
- Electrical wires:
  - Copper is used in making electrical wires because of its high electrical conductivity.
  - Copper is ductile and can be drawn into thin wire without breaking.
  - Also, copper can be bent and rolled into copper wire rolls without breaking.
  - Hence, copper is used in electrical wiring since it conducts electricity well, and is ductile and malleable.

Iron and steel:
- Pure iron consists of only iron metal, while steel is an alloy of iron and carbon, and sometimes other metals.
- However, items made of pure iron are rare, since pure iron is too soft to be made useful.
- Hence, most iron will have some carbon content, which leads to creation of steel.

Steel:
- Steel is an alloy of iron and carbon.
- There are different types of steel with different levels of carbon content.
- When the carbon content rises, steel becomes harder and stronger, but less malleable and ductile, in other words, more brittle.
- A higher carbon content also lowers the melting point.

Types of steel:
- Steel is broken down into four classes based on carbon content.
- Low-carbon steel:
  - It has about 0.20% carbon content.
  - The low-carbon steel is commonly known as mild steel.
- Medium-carbon steel:
  - It has about 0.5% carbon content.
  - Medium-carbon steel balances ductility and strength and has good wear resistance.
- High-carbon steel:
  - It has about 1% carbon content.
  - High-carbon steel is very strong and is commonly known as hard steel.
- Ultra-high-carbon steel:
  - It has about 2% carbon content.
  - This type of steel can be tempered to great hardness.

Uses of different types of steel:
- Low-carbon steel:
  - Mild steel is very important and used in many things.
  - It is used as structural steel, which is used in construction to strengthen concrete.
  - Mild steel is also used for car bodies, because it is malleable and can be beaten to different shapes.
  - Since mild steel is malleable and tough, it is used to make machinery for manufacturing.
- Medium-carbon steel:
  - Medium-carbon steel is used to make large bars because of its balance of ductility and strength.
  - In addition, it is used for steel forging and automotive components because it has a good wear resistance.
- High-carbon steel:
  - Because it is very strong, high-carbon steel is used in springs and edged tools, like knives.
  - High carbon steel is also used for high-strength wires.
- Ultra-high-carbon steel:
  - Ultra-high-carbon steel is used for ultra-high-carbon steel, axles or punches, where hardness really matters.

Stainless steel:
- Stainless steel is a steel alloy with a minimum of 10.5% chromium and a maximum of 1.2% carbon by mass.
- Stainless steel is corrosion resistant because of the chromium content.

Uses of stainless steel:
- Stainless steel is resistant to corrosion and very unreactive, so it is used for chemical and petrochemical plants.
- Since it is very unreactive, stainless steel is also used in hospitals, such as surgical instruments and tools.
- Stainless steel is also used for cutlery since it’s ideal for use for food preparation.
- Resistance to corrosion, the ease of cleaning, and unnecessary need for surface coatings means that stainless steel can be used in commercial kitchens and food processing plants.
- Stainless steel is mostly used for its strength, unreactivity, lustre, and resistance to corrosion and staining.

Galvanized steel:
- Galvanized steel is a steel alloy that has been coated with zinc.
- Galvanization is done to prevent rusting.

Brass:
- Brass is an alloy of copper and zinc.
- The proportions of copper and zinc can be varied to achieve varying mechanical and electrical properties.
- Compared to copper, brass is harder and has slightly worse electrical conductivity than copper.
- Brass is used to make instruments, electrical accessories as well as pipe fittings or connectors.

9.06 - Uses of Metals

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