Deformation microstructures developed by cold-rolling in Ti-added ultra low carbon steel have been investigated by the same site analyses for dislocation substructures and crystal orientation by employing the techniques of SEM-AsB and SEM-EBSD. Particular attention has been paid on the relationship between the characteristics of deformation microstructures and preferred crystallographic orientations after cold-rolling. Moreover, correlation between the formation of newly observed fine grains around grain boundaries and preferred orientations was also examined, taking into consideration the grain boundary characteristics.

Microstructural characteristics of each crystal orientation observed using AsB and EBSD are as follows: (1) grains with γ-fiber (ND//<111>) have relatively fine cell structures, where the micro bands or shear bands are frequently observed. (2) grains with the orientation of α-fiber (RD//<110>) have coarse cell structures except the case that they are γ-fiber. Nanoindentation tests for those microstructures demonstrated an orientation dependence in which the hardness of γ-fiber is higher than that of the other oriented fibers. Such orientation dependences of microstructures and hardness indicate that work hardening in γ-fiber is more enhanced than that in other fibers.

It is also to be noted that fine grains were observed around some grain boundaries. Many of those boundaries are adjacent to the γ-fiber, which indicates that new grains are formed in the vicinity of boundaries during cold-rolling although they are limited in well work-hardened grains.