What is the difference between hot working and cold working of metals?

Hot working is performed above the recrystallization temperature of the metal, allowing easier deformation, no strain hardening, and refinement of grain structure. Cold working is done below recrystallization temperature, resulting in strain hardening, improved surface finish, tighter tolerances, but requires more force and may cause residual stresses. Hot working is used for primary shaping while cold working is for finishing operations.