In spheroidising process, the steel is

A. Heated below the lower critical temperature and then cooled slowly

B. Heated up to the lower critical temperature and then cooled in still air

C. Heated slightly above the lower critical temperature and then cooled slowly to a temperature of 600°C

D. None of the above

Answer: Option C

Solution(By Examveda Team)

Spheroidizing of high carbon steel is a method of prolonged heating at a temperature below the eutectoid temperature.
By heating at this temperature pearlite, which is the lowest energy arrangement of steel, gets converted to ferrite and cementite. .
However, the process of spheroidizing does consume a lot of energy.