Metals as Building Materials

Metals are mostly used in construction. Building metals can be classified as ferrous or non-ferrous.

FERROUS METALS:

A ferrous material is a type of material that has iron as its main component. To create ferrous materials, iron ore is first turned into pig iron and then subjected to various metallurgical processes. These processes are used to mix different percentages of carbon to produce the following three useful ferrous materials:
1) Cast iron, which has a carbon content ranging from 1.7% to 4.5%,
2) Wrought iron, which has a carbon content ranging from 0.05% to 0.15%, and
3) Steel, which has a carbon content ranging from 0.25% to 0.25%. All ferrous materials have approximately 0.5% to 3% silica, less than 2% manganese, 0.15% sulfur, and 0.6% phosphorous.

1. Cast Iron:

Important properties of cast iron are:

The material in question has a compression strength of 700 N/mm2 and a tensile strength of 150 N/mm2.
It is brittle and, therefore, unable to absorb shocks.
Its specific gravity is 7.5.
The structure of the material is coarse, crystalline, and fibrous.
It is not magnetic and does not rust easily.
Additionally, it has a low melting point of approximately 1200°C.

 Uses of Cast Iron: 

Cast iron is used for various purposes, like making rainwater and sanitary pipes, sanitary fittings, manhole covers, railings, spiral staircases, fire gratings, covers for pumps and motors, and brackets.

2. Wrought Iron:

It is almost pure iron with less than 0.15% carbon. Other impurities are reduced during manufacturing.

Properties of Wrought Iron:

The material has an ultimate compressive strength of 200 N/mm2 and an ultimate tensile strength of 375 N/mm2.
It exhibits both ductile and brittle properties.
The unit weight of the material is 77 kN/m3.
It melts at approximately 1500°C and becomes malleable at 900°C, allowing two pieces to be joined by hammering.
The material is excellent at absorbing shocks.
Although it can form temporary magnets, it cannot be magnetized permanently.
It is prone to rusting.

Uses of Wrought Iron: 

• It is used for making nails, nuts, boots, wires, chains, roofing sheets, grills, fences, window guards, and more.

3. Steel:

Steel is a widely used building material. Three varieties of steel are commonly used:

1. Mild steel
2. High-carbon steel and
3. High tensile steel

1. Mild Steel:

The material has a maximum of 0.25% carbon, 0.055% sulphur, and 0.55% phosphorus.

Properties of Mild Steel:

It is a material that is both malleable and ductile.
It has higher elasticity and can be magnetized permanently.
Its specific gravity is 7.8
Its Young’s modulus is 2.1 × 10^5 N/mm2.
This material can be easily welded and is equally strong in both tension and compression.

Uses of Mild Steel:

Round bars are commonly used as reinforcement in reinforced concrete works.
Rolled sections such as I, T, L, C, plates, and others are utilized in constructing steel columns, beams, trusses, and more.
Tubular sections are used as poles and truss members.
Plain and corrugated mild steel are popular roofing materials.
Lastly, mild steel sections are used in fabricating parts of various machinery.

2. High-carbon steel: 

The steel contains carbon ranging from 0.7% to 1.5%.

 Properties of Carbon Steel:

It is tougher and more elastic than mild steel but difficult to weld. It can be magnetized permanently and is stronger in compression than in tension. It also withstands shocks and vibrations better.

Uses of High Carbon Steel:

High-carbon steel is used for making tools, such as drills, files, and chisels.
It is also commonly used to make machine parts due to its ability to withstand shocks and vibrations.

3. High Tensile Steel:
   

The steel contains 0.8% carbon and 0.6% manganese and is known for its high strength. It is commonly used for prestressed concrete works to make high-tensile steel wires.

ALUMINIUM

Most rocks and clay contain aluminum, but bauxite is the ideal ore to produce aluminum metal.

 Properties of Aluminum 

It has a silver color and a bright luster.
It is very lightweight and an excellent conductor of electricity.
It also has exceptional resistance to corrosion.
Its melting point is at 660°C.
Additionally, it is highly ductile and malleable, with a high strength-to-weight ratio.

Uses of Aluminum 

Aluminum is used for making door and window frames, structural members, wires, foils, and pigments in paints.

 COPPER

Copper is a metal that is found in nature in the form of ores which contain small amounts of iron and sulphur. The impurities are removed from the ores, and the metal is then processed electrolytically to obtain the purest form of copper. This metal is known for its durability and is almost indestructible. Copper scrap can also be processed to obtain the original copper.

Properties of Copper              

The material in question has a reddish-brown color and a crystalline structure. It is highly ductile and malleable and can resist corrosion. Furthermore, it can be easily welded at a red heat condition and dents can be hammered out. Additionally, it is known for its high electric and thermal conductivity and has a melting point of 1083°C.

Uses of Copper 

Copper is a versatile metal that has various applications.
It is commonly used as an electric wire and cable, as well as a lighting conductor.
Copper plates are also used to waterproof construction joints.
Additionally, copper tubes are utilized for hot and cold water supply, gas, and sanitation connections.
Moreover, copper is a significant component of brass and bronze.