Work Hardening

Work hardening, also known as strain hardening or cold working, is the strengthening of a metal by plastic deformation. This strengthening occurs because of dislocation movements and dislocation generation within the crystal structure of the material. Most non-brittle metals with a reasonably high melting point as well as several polymers can be strengthened in this fashion. Alloys not amenable to heat treatment, including low-carbon steel, are often work-hardened. Some materials cannot be work-hardened at normal ambient temperatures, such as indium, however others can only be strengthened via work hardening, such as pure copper and aluminum.

Work hardening may be desirable or undesirable depending on the context.

  • An example of undesirable work hardening is during machining when early passes of a cutter inadvertently work-harden the workpiece surface, causing damage to the cutter during the later passes. Certain alloys are more prone to this than others; superalloys such as Inconel require machining strategies that take it into account.
  • An example of desirable work hardening is that which occurs in metalworking processes that intentionally induce plastic deformation to exact a shape change. These processes are known as cold working or cold forming processes. They are characterized by shaping the workpiece at a temperature below its recrystallization temperature, usually at the ambient temperature. Cold forming techniques are usually classified into four major groups: squeezing, bending, drawing, and shearing. Applications include the heading of bolts and cap screws and the finishing of cold rolled steel.

Read more about Work HardeningHistory, Theory, Empirical Relations, Processes, Advantages and Disadvantages

Other articles related to "work hardening, work, hardening":

Strengthening Mechanisms Of Materials - Strengthening Mechanisms in Metals - Work Hardening
... The primary species responsible for work hardening are dislocations ... Dislocations interact with each other by generating stress fields in the material ...
Yield (engineering) - Factors Influencing Yield Stress - Strengthening Mechanisms - Work Hardening
... The governing formula for this mechanism is where is the yield stress, G is the shear elastic modulus, b is the magnitude of the Burgers vector, and is the dislocation density. ...
Handloading - Cost Considerations - Case Life Maximization
... generally last longer, as they will not be work hardened or flow under pressure as much as cases loaded to higher pressures ... Work hardening can cause cracks to occur in the neck as the hardened brass loses its malleability, and is unable to survive swaging back into shape during the resizing operation ... is often thought to greatly shorten case life by work hardening the full length of the case, which can cause the case neck to split, although some studies show that the number of reloads possible ...
Peening - Work Hardening
... Cold work also serves to harden the material's surface ... When a metal undergoes strain hardening its yield strength increases but its ductility decreases ... Strain hardening actually increases the number of dislocations in the crystal lattice of the material ...
Work Hardening - Advantages and Disadvantages
... into the metal Contamination problems are minimized The increase in strength due to strain hardening is comparable to that of heat treating ... Therefore, it is sometimes more economical to cold work a less costly and weaker metal than to hot work a more expensive metal that can be heat treated, especially ... During cold working the part undergoes work hardening and the microstructure deforms to follow the contours of the part surface ...

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