Külmtöötlus

Külmtöötlus, also known as cold working, is a metal forming process that occurs below the recrystallization temperature of the metal. This means that the material is deformed at a temperature where it does not recrystallize or regain its original grain structure. Common cold working processes include rolling, drawing, bending, and extrusion.

The primary advantage of cold working is that it significantly improves the mechanical properties of the metal, such as its tensile strength, yield strength, and hardness. This is due to the introduction of dislocations within the metal's crystal lattice, which impede further dislocation movement, a phenomenon known as work hardening or strain hardening. Cold working also results in a superior surface finish and often tighter dimensional tolerances compared to hot working.

However, cold working also has drawbacks. The increased strength comes at the expense of ductility, making the material more brittle and prone to fracture. Higher forces are required for deformation, necessitating more robust machinery. Furthermore, internal stresses are introduced into the material, which may require a subsequent annealing process to relieve. Despite these limitations, cold working is widely employed in industries like automotive, aerospace, and manufacturing for producing components that require high strength, precision, and good surface quality.