Evolution of recrystallization texture in nonoriented electrical steels

Whereas much research has been carried out on the texture development of Fe–Si steels or low carbon steels, very little attention has been given to the texture formation and investigation of the underlying mechanisms in Fe–Cr steels. Ferritic stainless steels containing between 11 and 17%Cr establish an important group of alloys owing to their good mechanical behaviour and corrosion resistance. Various industrial problems, such as roping or optimisation of deep drawability, can be tackled by means of quantitative texture analysis. Therefore, fundamental aspects concerning the inhomogeneity of the hot and cold rolled band, the origin of Goss texture after annealing, and selective particle drag during recrystallisation of alloys with finely dispersed Nb and Ti carbonitrides have been discussed.MST/1678

Textures of ferritic stainless steels

Experimental evidence concerning the evolution of textures and substructures during cold rolling of low–carbon steel is presented and reviewed with some reference to the importance of these during subsequent annealing. Attention is paid to the orientation dependence of microstructure and stored energy of deformation. These are considered in relation to the Taylor factors for grains of different orientations in homogeneous deformation, and to the occurrence of different types of heterogeneity. Certain grain–scale heterogeneities appear to be important in defining the textures, which can now be predicted with some success using so–called relaxed constraint models. Intragranular heterogeneities also play a role and these especially affect the variation in substructure between grains. The strain–rate sensitivity of flow stress is an important parameter, which, depending on its sign and magnitude, may cause either severe strain localization in shear bands or lead to very homogeneous deformation structures where the influence of crystal orientation almost disappears.

Deformation microstructures and textures in steels

Retention of the Goss orientation between microbands during cold rolling of an Fe3%Si single crystal

Recrystallisation textures in iron resulting from nucleation at grain boundaries

A number of experiments involving cold rolling and annealing have been carried out on polycrystalline and single crystal silicon iron. It is shown that the microstructural state just beneath the surface of the sheet before cold rolling is an important factor in the successful development of Goss texture during simulated processing. A coarse grained surface zone encourages formation of shear bands during rolling and these become preferential sites for nucleation during primary recrystallization. Nucleation of secondary grains, which also occurs just beneath the sheet surface, appears to be dependent on the prior existence of the shear band structure. Single crystals with the orientation (111)[112] are prone to shear banding during cold rolling especially when strain aging conditions are established. During subsequent annealing the shear bands recrystallize first, producing new grains which have the Goss orientation. The texture after complete recrystallization is the same as that of the shear band ...

W. B. Hutchinson

Papers

Contribution of shear banding to origin of Goss texture in silicon iron