coldworking

Coldworking, or cold forming, refers to shaping metal below its recrystallization temperature, typically at or near room temperature. It is contrasted with hot working, which is performed above recrystallization temperature.

The primary mechanism is work hardening (strain hardening): plastic deformation introduces dislocations that impede further movement, increasing yield strength and hardness while reducing ductility and toughness. Cold work can also introduce residual stresses and cause surface hardening, enabling tighter tolerances and improved surface finish.

Common processes include cold rolling, drawing, extrusion, pressing, bending, punching, and metal spinning. These processes generally produce parts with better dimensional accuracy and surface finish and with higher strength, but at the cost of higher forming forces, greater tool wear, and increased risk of cracking in susceptible alloys.

Many metals are suitable for cold working, notably steel, aluminum, copper, brass, nickel alloys, titanium, and gold used in jewelry. The degree of work hardening varies by material; brittle or highly alloyed metals may require care to avoid cracking or fracture.

Post-processing often involves annealing or stress-relief heat treatment to restore ductility and reduce residual stresses, depending on alloy and end-use requirements.

Applications include wires, tubes, sheets, automotive components, fasteners, and decorative items such as jewelry that benefit from improved surface finish and dimensional accuracy.