The heat treatment process used for softening hardened steel is
A. Carburising
B. Normalizing
C. Annealing
D. Tempering
Answer: Option C
Solution (By Examveda Team)
Definition: Annealing is a heat treatment process in which hardened steel is heated to a temperature above its critical point, held for a specific duration, and then cooled slowly, usually in a furnace.Purpose: The primary aim of annealing is to soften hardened steel, improve its ductility, relieve internal stresses, and refine the grain structure for better machinability.
Reason: Slow cooling during annealing transforms the steel’s microstructure into a softer and more workable form, making it suitable for further machining or shaping operations.
Why not tempering: Tempering also reduces hardness but its main purpose is to reduce brittleness and improve toughness while retaining most of the hardness; it does not fully soften the steel like annealing.
Conclusion: For complete softening of hardened steel, annealing is the correct and standard heat treatment process.
This Question Belongs to Mechanical Engineering >> Engineering Materials
The correct answer is ANNEALING
The heat treatment process used to soften hardened steel is called annealing. Annealing involves heating the steel to a specific temperature, holding it there for a period, and then slowly cooling it down. This process reduces hardness, relieves internal stresses, and improves ductility and machinability.
Both option C and D are correct.