Kylmävetäminen

Kylmävetäminen, or cold drawing, is a metalworking process used to improve the mechanical properties of wires, rods, and tubes. It involves pulling a metal workpiece through a die at or near room temperature. This process plastically deforms the metal, elongating it and reducing its cross-sectional area.

The primary benefit of cold drawing is work hardening, also known as strain hardening. As the metal is deformed, dislocations within its crystalline structure become entangled, making it more difficult for them to move. This increased resistance to dislocation movement translates into higher tensile strength, yield strength, and hardness. It also often improves surface finish and dimensional accuracy.

However, cold drawing also increases the brittleness of the metal, reducing its ductility. To counteract this, cold-worked parts may undergo annealing, a heat treatment process that softens the metal by allowing recrystallization and reducing dislocation density.

Common materials that undergo cold drawing include steel, aluminum, copper, and brass. The process is widely used in manufacturing fasteners, springs, automotive parts, and structural components where precise dimensions and enhanced strength are required. The specific die shape and reduction in area are carefully controlled to achieve desired material properties and final product dimensions.