How does cold forging affect a metal's properties?

Cold forging is a process that involves deforming metal at room temperature, which results in a significant alteration of its physical properties. When metal is cold forged, the dislocation density within its crystal structure increases. This means that the internal lattice structure becomes more complex and entangled, which impedes the movement of dislocations during deformation. As a result, the metal exhibits an increase in strength and hardness, a phenomenon known as strain hardening or work hardening.

In addition to strength and hardness improvements, cold forging generally leads to better surface finish and dimensional accuracy due to the control that can be exerted during the forming process. However, while cold forging does enhance strength and hardness, it does not typically improve ductility and flexibility, as those properties often decrease with increased strength. Moreover, the weight of the metal does not change significantly due to cold forging, nor does the process inherently improve corrosion resistance.

These attributes make cold forging a valuable method in manufacturing processes where high-performance, strong components are necessary. Such properties are desired in various applications, from automotive parts to aerospace components, where both strength and precise dimensions are critical.