Question

In cold working of steel

• A. Grain structure does not change
• B. Internal stresses disappear
• C. Strength and hardness increases
• D. It is heated above recrystallisation temperature

Hint:

Cold working improves strength and hardness through dislocation accumulation, but it reduces ductility and may introduce residual stresses.

Answer 1

The Correct Option is C

Cold working refers to the plastic deformation of metals below their recrystallization temperature, usually at room temperature. In this process: - Grain structure is distorted, not preserved. - Internal stresses are introduced, not eliminated. - Strength and hardness increase due to strain hardening. - It is not heated above the recrystallization temperature (this would be hot working). Therefore, among the given options, the only correct statement is that strength and hardness increases during cold working.