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The magnetic properties of nonoriented electrical steels are influenced by grain size and texture. During the final annealing process, heating rate, annealing temperature and time, and cooling rate are the main factors which can influence the formation of annealing texture. Among these parameters, heating rate is more effective in controlling texture development through changes in the recovery and recrystallization processes. Therefore, it can provide the means to decrease core loss and increase permeability. In nonoriented electrical steels with different initial grain sizes, the effect of heating rate on texture development during final annealing is examined, and the reasons for texture changes are discussed. The average grain size decreases with the increase in heating rate both in the coarse-grained and in the fine-grained specimens. In the coarse-grained specimen, the Goss texture is significantly strengthened but the {111}‹112› texture component is slightly weakened as heating rate increases. On the other hand, in the fine-grained specimen, the {111}‹112› intensity is greatly decreased but the Goss intensity is slightly increased as the heating rate increases. The heating rate up to the annealing temperature affects texture formation differently depending on the initial grain size prior to cold rolling. These differences are mainly related to the difference in the number of shear bands formed during cold rolling in grains having different sizes.

This study investigated the effect of the initial solidified structure on the ridging phenomenon and the texture in type 430 ferritic stainless steel sheets that have α+γ two-phases at high temperature. The initial solidified structure with equiaxed or columnar grains was used and the effect of annealing of hot-rolled sheet on the texture formation during cold rolling and annealing was investigated. The effect of the initial solidified structure on the ridging phenomenon differed depending on annealing of hot-rolled sheet. With annealing of hot-rolled sheet, the columnar grain specimen exhibited severer ridging than the equiaxed grain specimen. On the other hand, without annealing of hot-rolled sheet, there was no effect of the initial solidified structure, and both specimens showed slight ridging. The columnar grain specimen with {001}‹uv0› initial texture had strong {001}‹110› texture after hot rolling and annealing, and the grain colonies with {001}‹110› and {112}‹110› orientations were identified after cold rolling and annealing. However, without annealing of hot-rolled sheet, the equiaxed and columnar grain specimens showed roughly random textures. In the case without annealing of hot-rolled sheet, the deformation zone forming around the hard α′ phase during cold rolling was effective for no influence of the initial solidified structure and the microstructure before cold rolling.

In a conventional production of deep-drawable steel sheets, a hot rolling in austenite and a cold rolling at room temperature together with a subsequent recrystallization annealing are applied to achieve a desired texture in the final cold strip. As a cost saving replacement for this, a thin-gauge hot strip with a required deep-drawability can be employed by applying the ferritic rolling with the finishing shifted down into the temperatures below Ar 1 . To optimize the process parameters, laboratory tests on an IF steel were carried out by using the hot deformation simulator WUMSI. By the measurements of the texture development as well as by the computing of r-values, the texture formation in a hot strip after ferritic rolling could be optimized achieving a deep-drawability in hot strips comparable to that of a cold strip.

In order to clarify the texture of TiN diposited onto (011) [100] single crystals of silicon steel, TiN ceramic coating by the HCD method was done on the surface of polished silicon steel samples. Pole figures of the TiN films and related silicon steel samples were measured simultaneously using an SSD auto pole figure apparatus. (111)TiN pole figure of the TiN film showed the dominant texture of (111) [110] orientation, and (100)Si-steel pole figure of the (011) [100] single crystal of silicon steel showed the dominant texture of (011) [100] orientation. The orientation relationship between the TiN films and a single crystal of silicon steel is considered to be (111)TiN//(011)Si-steel, [110]TiN//[100]Si-steel. It should be noted that the dominant texture of TiN with (111) [110] orientation was formed preferentially on the surface of (011) [100] single crystal of silicon steel, and the orientation relationship between the TiN films and a single crystal of silicon steel was very good misfit within several percent.

The mechanism of improving r-value of continuously annealed steel sheets by high temperature hot-coiling in Cu-bearing ultra low C interstitial-free (IF) steel has been investigated, by using the hot-bands heat-treated at different temperatures from 500 to 800°C in order to change the morphology of pre-precipitates in hot-bands. By the ODF analysis of recrystallization texture, it was clarified that the γ-fiber texture ( //ND) extremely developed by the heat-treatment at the temperature ranging from 720 to 760°C. TEM observations also revealed that the complex-precipitates composed of Ti-carbosulfide and Cu were observed only in the same range of heat-treating temperature. Improvement of r-value by high temperature hot-coiling is caused by the precipitation of Cu combined with coarse Ti-carbosulfides which avoids the detrimental influence of fine pre-precipitation of Cu in matrix.

To realize a remarkable improvement of the deep drawability of steel sheets, the formation of texture of Ti-bearing IF steel sheets has been investigated throughout the rolling and annealing processes. Initially, the formation of hot band textures has been investigated in terms of the influence of rolling temperature and reduction. A low carbon steel sheet has been also studied to clarify the features of IF steel sheets. Subsequently, the textures formed by rolling and annealing has been studied at the surface and the midplane of IF steel sheets. The formation of the recrystallization texture has been discussed taking into consideration of the stored energy and the crystal rotation relationship around the axes between the orientation of the recrystallized grain and the surrounding deformed matrix. It was also shown that the consideration of the local crystal rotations in the vicinity of grain boundaries due to rolling facilitates the understanding of the formation of the recrystallization texture. The obtained results led to the conclusion that the α-region hot rolling under cartain conditions is a very effective means of improving the deep drawability of IF steel sheets.

The mechanism of the texture formation in low carbon steels is not fully understood as yed. To clarify this, a series of systematic investigations has been made. Summarizing these results and comparing these with those of other investigations, possible mechanisms of texture formation are discussed. In polycrystalline iron, deformation and recrystallization in grain boundary regions play the most important role in the texture formation. In this respect, results obtained on single and bi-crystals do not provide much informations. In polycrystals, crystal rotation occurs during rolling along different paths from that observed in single crystals, affected by grain boundary constraints significantly. Approaches to the stable end orientation seems to be closely related with the development of the stable dislocation substructures. The development of the rolling texture is therefore strongly affected by the metallurgical factors that influence the evolution of the dislocation substructures. {111} recrystallized grains seem to be formed from the grain boundary regions of the same orientation through the subgrain growth mechanism.

Effects of inhomogeneous shear strain on the texture variation through the thickness of hot rolled ferritic stainless steel sheets are studied. The changes in texture with the progress of recrystallization are also investigated. Sheet specimens of AISI430 stainless steel are rolled at 1 000°C at a rolling speed of 20 m/s without lubrication and quenched into water at an interval of 3.5 to 250 ms after rolling. The redundant shear deformation by friction produces a severely sheared region beneath the surface, where a band of extremely fine recrystallized grains is formed when the strain exceeds a critical value.‹110› || ND axis density increases and ‹111› || ND axis density decreases with increasing shear strain. The deformation texture in the severely sheared region mainly consists of {110}‹001›, {110}‹112› and {112}‹111›. At the mid-thickness, it consists of ‹111› || ND and ‹100› || ND components. Only shear deformation is required for the formation of {110}‹001› texture. The sharpness of the preferred orientation decreases by the progress of recrystallization, but some components of deformation texture are retained throughout the thickness after recrystallization is completed.