cold work, Cold work - Theory, Cold work - Dislocations and Lattice Strain Fields, Cold work - Elastic and Plastic Deformation, Cold work - Example, Cold work - Increase of dislocations and <b>Cold Work</b>, Taxonomy of manufacturing processes for various cold work processes, Cold rolling, Work hardening
Temperare (to mix correctly) is the Latin origin of words like "temperature" and "tempering"; it and "tempo" come, in turn, from tempus (time or season). Thus, the word "temper" can refer (at least informally) to any time- and temperature-sensitive process (as for chocolate tempering or tempered glass), a material's thermo-mechanical history (including cold work and cryogenic hardening), or even its composition.
Temper may mean:
Tempering, in metallurgy, a heat treatment technique for metals and alloy
Cryogenic hardening is a heat treatment in which the material is cooled to cryogenic temperatures, usually using liquid nitrogen. It can have a profound effect on the mechanical properties of certain steels, provided their composition and prior heat treatment are such that they retain some austenite at room temperature. It is designed to increase the amount of martensite in the steel's crystal structure, increasing its ...
Work hardening is an increase in mechanical strength due to plastic deformation. In metallic solids, permanent change of shape is usually carried out on a microscopic scale by defects called dislocations which are created by stress and rearrange the material by moving through it. At low temperature, these defects do not anneal out of the material, but build up as the material is worked, interfering with one another's motion and thereby increasin ...
Texture can be determined directly by Laue photography or the EBSD-method (electron backscatter diffraction) in Scanning Electron Microscopes. Other methods of x-ray crystallography and of diffraction in general offer indirect measures of texture.
Texture is often represented using a pole figure, in which a specified crystallographic axis (or pole) from each of a representative number of crystallites is plotted in a stereographic projection, along with directions relevant to the material's processing history such as th ...
Cold work also serves to harden the material's surface. This makes cracks less likely to form at the surface and provides resistance to abrasion. 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. When a material has a great number of dislocations, plastic deformation is hindered, and the material will continue to behave in an elastic way well beyond the elastic yield s ...
Plastic deformation induces a residual compressive stress in a peened surface, along with tensile stress in the interior. This stress state resembles the one seen in toughened glass, and is useful for similar reasons.
Surface compressive stresses confer resistance to metal fatigue and to some forms of corrosion. The tensile stresses deep in the part are not as problematic as tensile stresses on the surface because crack ...
