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In metallurgy, cold forming or cold working is any metalworking process in which metal is shaped below its recrystallization temperature, usually at the ambient temperature.. Such processes are contrasted with hot working techniques like hot rolling, forging, welding, etc. [1]: p.375 The same or similar terms are used in glassmaking for the equivalents; for example cut glass is made by "cold ...
Cold working generally results in a higher yield strength as a result of the increased number of dislocations and the Hall–Petch effect of the sub-grains, and a decrease in ductility. The effects of cold working may be reversed by annealing the material at high temperatures where recovery and recrystallization reduce the dislocation density.
Cold working of metal increases the number of dislocations by the Frank–Read mechanism. Higher dislocation density increases yield strength and causes work hardening of metals. The mechanism of dislocation generation was proposed by and named after British physicist Charles Frank and Thornton Read .
Forming is the process of reshaping metal without adding or removing material.. Hot working. Hot rolling; Carburizing; Drawing; Forging; Forge weld; Oxidising; Extruding; Cold working ...
Metals can be heat treated to alter the properties of strength, ductility, toughness, hardness or resistance to corrosion. Common heat treatment processes include annealing, precipitation hardening, quenching, and tempering: annealing softens the metal by allowing recovery of cold work and grain growth.
The manufacturing process involves forming the material by either press-braking or cold roll forming to achieve the desired shape. When steel is formed by press-braking or cold rolled forming, there is a change in the mechanical properties of the material by virtue of the cold working of the metal.
Thus, the process may be introduced as a deliberate step in metals processing or may be an undesirable byproduct of another processing step. The most important industrial uses are softening of metals previously hardened or rendered brittle by cold work, and control of the grain structure in the final product. Recrystallization temperature is ...
Hot working or cold working after the annealing process alters the metal structure, so further heat treatments may be used to achieve the properties required. With knowledge of the composition and phase diagram , heat treatment can be used to adjust from harder and more brittle to softer and more ductile.