珪素鋼熱延板表面近傍の板厚方向への組織変化

抄録

Computer color mapping of the crystallographic orientation and lattice strain was performed on elongated and recrystallized grains at various thickness positions in the hot-rolled silicon steel sheet.
(1) At the 1/20 depth beneath the surface, in addition to the grains elongated in the rolling direction, “plate-like” elongated grains formed, with a rotation in the crystallographic plane of (110). These elongated grains comprised transverse deformation bands across a grain. Many recrystallized grains with random orientations formed preferentially at the grain boundary and in the deformation band, and were large, with an average grain size of 136 μm.
(2) At the 1/10 depth beneath the surface, the size of the elongated grains was heterogeneous. The elongated grains with Goss orientation were extremely large, and many small areas free from strain were present in the Goss-oriented grains.
(3) At the 3/20 depth beneath the surface, the grains elongated in the rolling direction and small-sized grains in the transverse direction formed with high frequency, and the elongated grains with Goss orientation became scarce. Recrystallized grains formed mainly at the grain boundary, but were small in size and relatively infrequent.
(4) The average size of the elongated grains at the 1/10 depth beneath the surface, where the elongated grains with Goss orientation formed, was the largest. These grains were smaller in the order of 3/20 and 1/20 depth.
(5) The formation frequency of recrystallized grains was smaller and less as the depth from the surface of the hot-rolled silicon steel sheet increased.