Page 134 - WCS - Electrical

WORKSHOP CALCULATION & SCIENCE - CITS

• Steels and Alloy steels

Different processes are used to produce iron and steel.
Pig-iron (Manufacturing process)
Pig-iron is obtained by the chemical reduction of iron ore. This process of reduction of the iron ore to Pig-iron is
known as SMELTING.
The main raw materials required for producing Pig-iron are:
• Iron ore
• Coke
• Flux
Iron ore

The chief iron ores used are:
• magnetite
• hematite
• limonite

• carbonite.
These ores contain iron in different proportions and are naturally available.
Coke
Coke is the fuel used to give the necessary heat to carry on the reducing action. The carbon from the coke in the
form of carbon monoxide combines with the iron ore to reduce it to iron.
Flux
This is the mineral substance charged into a blast furnace to lower the melting point of the ore, and it combines
with the non-metallic portion of the ore to form a molten slag.
Limestone is the most commonly used flux in the blast furnace.
Properties and use of Pig-iron
Pig-iron is, therefore, refined and remelted and used to produce other varieties of iron and steel.
Cast Iron (Manufacturing process)

The pig-iron which is tapped from the blast furnace is the crude form of raw material for the cupola, and should
be further refined for making castings. This refining is carried out in the cupola furnace which is a small form of
a blast furnace.
Generally cupolas are not worked continuously like blast furnaces but are run only as and when required.
Cast Iron (Types)
Cast iron is an alloy of iron, carbon and silicon. The carbon content ranges from 2 to 4%.
Types of cast iron

The following are the types of cast iron.
• Grey cast iron
• White cast iron
• Malleable cast iron

• Nodular cast iron
Grey cast iron
This is widely used for the casting of machinery parts and can be machined easily.

121

CITS : WCS - Electrical - Exercise 11