Answer:
(d) Spheroidizing
Explanation:
Spheroidizing
This is the heat treatment process for steel which having carbon percentage more than 0.8 %.As we know that a hard and brittle material is having carbon percentage more than 0.8 %.That is why this process is suitable for the hard materials.
In this process a hard and brittle materials convert into soft and ductile after this it improve the machine ability as well as improve the tool life.
In this process grain become spheroidal and these grains are ductile.
