Q1: Classification of metal forming processes into hot and cold working is based on the following parameters.

ANS:B - Recrystallisation temperature.

The classification of metal forming processes into hot and cold working is primarily based on the recrystallization temperature of the material. Explanation:

1. Hot working: Hot working processes involve deforming metals at temperatures above their recrystallization temperature but below their melting point (solidus temperature). At these elevated temperatures, the metal is more ductile and exhibits lower strength and higher deformability. Hot working processes include forging, rolling, extrusion, and hot stamping. These processes are typically used for materials that are difficult to deform at room temperature, such as steel and aluminum alloys.
2. Cold working: Cold working processes involve deforming metals at temperatures below their recrystallization temperature. In cold working, the metal is deformed at room temperature or slightly elevated temperatures, leading to strain hardening and increased strength. Cold working processes include cold rolling, cold forging, cold extrusion, and drawing. These processes are commonly used to produce parts with tight tolerances, smooth surface finish, and improved mechanical properties.

While other parameters such as stacking fault energy and transformation temperature may influence the behavior of materials during metal forming, the primary determinant for classifying processes into hot and cold working is the recrystallization temperature. Processes performed above this temperature are classified as hot working, while those performed below this temperature are classified as cold working.