Question

Which of the following heat treatment processes is used for softening hardened steel?

• A. Carburizing
• B. Normalizing
• C. Annealing
• D. Tempering

Hint:

Annealing involves heating steel to a temperature above its recrystallization point, holding it at that temperature, and then allowing it to cool slowly in a furnace.

Answer 1

The Correct Option is C

Heat treatment processes are used to modify the mechanical properties of steel. When steel becomes hardened due to previous heat treatment or work hardening, it can be softened using specific processes. Step 1: Understanding Different Heat Treatment Processes - Carburizing (Option A): A surface hardening process that increases the carbon content in the outer layer of steel, making it harder.
- Normalizing (Option B): A process used to refine grain structure and improve toughness but does not primarily soften hardened steel.
- Annealing (Option C): A heat treatment process that softens steel by heating it to a high temperature and then slowly cooling it. This relieves internal stresses and increases ductility.
- Tempering (Option D): Used to reduce brittleness and improve toughness but does not significantly soften hardened steel.


Step 2: Identifying the Correct Answer Since annealing is specifically used to soften hardened steel, the correct answer is option (C) Annealing.