Mechanical Engineering - Engineering Materials - Discussion

Tempering: Tempering reduces the hardness in the martensite by transforming it into various forms of tempered martensite. Tempering is a heat treatment technique applied to ferrous alloys, such as steel or cast iron, to achieve greater toughness by decreasing the hardness of the alloy.

Annealing/Normalising: Annealing is a heat treatment process which alters the microstructure of a material to change its mechanical or electrical properties. Typically, in steels, annealing is used to reduce hardness, increase ductility and help eliminate internal stresses.

There is some confusion, we know that annealing is done for softening a piece of steel, but in question mentioned that what is done to soften a hardening steel?

That means after hardening, we must go for tampering, it is also done for the expanse of hardness.

The process of heat treatment of steel is in order of = annealing - normalizing (equilibrium condition) and hardening-tempering (non-equilibrium condition). So option D is correct.

Annealing is a primary hardening process while tempering is a secondary hardening process. Tempering is done to increase the toughness of the steel by reducing the hardness of the alloy.

It is done after hardening the steel in order to remove the brittleness. Since it it mentioned that hardened steel, tempering would be the answer.

Tempering is hardening process.

Anealing is softening.

Annealing is a process of softening the steel.

Tempering is to reduce internal stress. Annealing is to soften the material.

Tempering is a process of heat treating, which is used to increase the toughness of iron-based alloys. Tempering is usually performed after hardening, to reduce some of the excess hardness, and is done by heating the metal to some temperature below the critical point for a certain period of time, then allowing it to cool in still air.

What is the difference between Annealing and Tempering?

Annealing is also used to soften the hardened steel.

Hardened steels are softened by normalizing.

This all are used for reducing hardness.