külmtöötlemine

Külmtöötlemine is an Estonian term referring to cold working processes in materials science and manufacturing. It encompasses a range of metal forming techniques performed at or near room temperature, below the material's recrystallization temperature. The primary goal of cold working is to shape a metal component while simultaneously improving its mechanical properties, such as strength and hardness, through strain hardening.

Common cold working processes include cold rolling, cold drawing, cold forging, and stamping. Cold rolling involves passing metal between rollers at room temperature to reduce its thickness and improve its surface finish and dimensional accuracy. Cold drawing is used to produce wires, bars, and tubes by pulling metal through a die with a smaller opening. Cold forging shapes metal by applying compressive forces at room temperature, often resulting in strong and precise parts. Stamping utilizes dies and punches to cut, bend, or form sheet metal into desired shapes.

The key advantage of külmtöötlemine is that it avoids the oxidation and scaling associated with hot working, leading to superior surface quality and tighter tolerances. However, it requires more force than hot working and can induce residual stresses in the material. The extent of strain hardening is dependent on the amount of deformation. If the deformation is too large, the material may become brittle and prone to fracture. Therefore, annealing may be required between cold working stages to restore ductility. Külmtöötlemine is widely used in industries like automotive, aerospace, and electronics for producing components with demanding specifications.