COMPUTER COLOR MAPPING ANALYSES OF DEFORMATION BANDS AND RECRYSTALLIZED GRAINS INSIDE ELONGATED GRAINS NEAR-SURFACE OF HOT-ROLLED SILICON STEEL SHEET

Computer color mapping of elongated grains near the surface of hot-rol led silicon steel sheet was performed with an image analyzer, using th e data of crystallographic orientation and strain obtained from a Koss el pattern examination. Matrix bands having two equivalent orientation s of near (210) [<(1)over bar 23>] and (210) [1(2) over bar3$] elongat ed grains formed alternately near the surface of hot-rolled silicon st eel sheet. The characteristic morphology comprised transverse deformat ion bands across a grain elongated in the rolling direction. The misor ientation between the matrix bands separating the deformation bands wa s 40 degrees (max.), whereas that inside each matrix band was 3-12 deg rees. Most deformation bands are bordered by high angle grain boundari es with a width of 3 pixels, and are of complicated and highly curved form inside the elongated grain. The elongated grains which were of ne ar {111}[112] orientation had a large amount of strain and formed smal l recrystallized grains by strain induced boundary migration from the high energy area at the grain boundaries or from the deformation bands within the elongated grains. The type and formation mechanism of the recrystallized grains can easily be observed by color mapping.