Question

What is the difference between pig iron and steel?

Answer 1

Pig iron and steel mainly contain iron. Pig iron is obtained by the smelting process of iron in the blast furnace. Steel is an ally of iron. Steel contains carbon, sulphur, silicon, phosphorus, manganese in small amounts. The main content of pig iron and steel is iron only the proportion varies.

Complete answer:
The differences in the properties of pig iron and steel are summarized in the table as follows:

Pig Iron	Steel
Pig iron contains more than 2 % carbon.	Steel contains less than 2 % carbon.
Pig iron is obtained by processing of iron ore in the blast furnace in presence of coke.	Steel is obtained by the processing of pig iron.
Pig iron is brittle in nature i.e. it breaks easily.	Steel is tough in nature.
Pig iron cannot be welded	Steel can be welded.
Pig iron cannot be rolled into sheets.	Steel can be rolled into sheets i.e. it is malleable.
Pig iron cannot absorb shock.	Steel can absorb shock.
Pig iron can rust.	Steel does not rust.
Pig iron melts at ${1200^ \circ }{\text{C}}$.	Steel melts at ${1300^ \circ }{\text{C - 140}}{{\text{0}}^ \circ }{\text{C}}$.

Note: Pig iron cannot be used for different engineering applications as it is brittle. But steel is used widely.
Pig iron is thus only used for making steel.
Steel has various uses like construction of roads, railways, buildings, etc. The maintenance of steel is easier as it does not rust.