The cold rolling texture of low and extra low carbon steels is primarily made up of a nearly perfect normal direction (ND) fibre and of two other components, centred at 001 and 112 , which...

Cold rolling and annealing textures in low carbon and extra low carbon steels

Deformation-related recrystallization processes

The evolution in microstructure and local crystallography is described, with emphasis on the behaviour of medium to high stacking fault energy FCC metals deformed at low temperature. This evolution is analysed within a common framework of grain subdivision on different size scales. The largest scale is the macroscopic subdivision of crystals or grains, which will be presented using the behaviour of single crystals as an example. Subdivision on smaller scales is demonstrated for polycrystals, with emphasis on the effects of strain and grain orientation on the evolution in microstructure and local crystallography. This leads to an introduction of structural parameters and their analysis using a scaling hypothesis. A key finding is the correlation between structure and crystallographic orientation, which allows a slip pattern description by standard crystal plasticity models leading to an analysis of the relationship between slip pattern and microstructure. These findings are briefly related to the macroscopic properties of deformed metals.

Development of microstructure in FCC metals during cold work

A thermomechanical process for grain refinement in precipitation hardening aluminum alloys is reported. The process includes severe overaging, deformation, and recrystallization steps. Microstructural studies by optical and transmission electron microscopy of grain refinement in 7075 aluminum have revealed that precipitates formed during the overaging step create preferential nucleation sites for recrystallizing grains. The relationship between precipitate density following severe overaging and recrystallized grain density has been investigated; the results show that the localized deformation zones associated with particles larger than about 0.75 μ m can act at preferential nucleation sites for recrystallizing grains. The density of particles capable of producing nucleation sites for new grains is approximately ten times greater than the density of recrystallized grains. A close relationship between dislocation cell size after the deformation step and recrystallized grain density has also been established. Both quantities saturate for rolling reductions larger than approximately 85 pct. The grain size produced in 2.5 mm thick sheet by the optimum processing schedule is approximately 10 μm in longitudinal and long transverse directions and 6 μm in the short transverse direction.

Grain refinement in 7075 aluminum by thermomechanical processing

The development of texture and plastic anisotropy (γ-value) during the annealing of low-carbon steel is described. The effects of various industrial processing parameters are considered as well as ...

Development and control of annealing textures in low-carbon steels

Transition bands are regions of high lattice distortion which result from inhomogeneous deformation in metals. During annealing of cold-worked metals, nucleation of recrystallization is frequently observed to occur within these bands. An analysis has been made of some of the conditions under which transition bands may develop during deformation, and of the factors which influence their microstructure. A model is proposed for the mechanism by which nucleation of recrystallization occurs in transition bands during annealing. The dependence of these processes on crystallographic orientation is then discussed and related to the formation of recrystallization textures in b.c.c. metals.

W. B. Hutchinson

Papers

Transition Bands and Recrystallization in Metals

Texture Development during Grain Growth in Low Carbon Steel Sheet