Answer :

Solution :

- At 1539°C, iron cools from liquid to solid, it is in BCC structure and it is in δ-Ferrite stage.
- After cooling in temperature range from 1400°C to 910°C it contains FCC structure which is also known as γ-Austenite.
- After again cooling below 910°C, α-ferrite phase will start.
- 768°C temperature line in diagram is known as Curie point temp line, because it distinguishes the metal property as Magnetic and non-magnetic.
- Above 768°C, the metal is non-magnetic and below 768°C the metal is magnetic