Mechanical Engineering - Workshop Technology - Discussion

The correct answer is: below the recrystallisation temperature.

Cold working of metals is carried out at a temperature below the recrystallization temperature. This is because cold working involves deforming the metal at a temperature where the metal's crystal structure is stable, and the metal behaves elastically.

Recrystallization temperature is the temperature at which the metal's crystal structure begins to change, and the metal starts to soften. Working below this temperature ensures that the metal retains its strength and hardness.

Here's why the other options are incorrect:

- At the recrystallization temperature (option 1), the metal starts to soften, making it unsuitable for cold working.
- Above the recrystallization temperature (option 3), the metal is in the hot working range, where it becomes softer and more prone to deformation.
- At any temperature (option 4) is incorrect because cold working requires a specific temperature range, below the recrystallization temperature.

Cold working is used to improve the mechanical properties of metals, such as strength, hardness, and ductility while maintaining their original shape and structure.

The temperature at which Deformed grain crystal structure replace by new stress free grains.

What is recrystallization temperature?