Effect of Initial Orientation on the Recrystallization Behavior of Solidified Columnar Crystals in a 19% Cr Ferritic Stainless Steel

The effect of the initial orientation of each grain on the recrystallization behavior at 973 K after 70% cold-rolling of solidified columnar crystals in a 19%Cr ferritic stainless steel have been investigated. It was demonstrated that the recrystallization kinetics, the recrystallization microstructure and the orientation of recrystallized grains in each columnar grain strongly depend on the initial orientation. The (001)[100] initially-oriented grains which showed the cold-rolled structure composed of fine elongated deformation bands readily recrystallized and formed fine recrystallized grains. On the other hand, the (001) [110] initially-oriented grains which showed a smooth-etching deformation structure were difficult to recrystallize and formed coarse recrystallized grains after long-time annealing. Because of this difference in the recrystallization behavior among columnar grains, the fully recrystallized structure of the columnar crystal specimen was extremely inhomogeneous in grain size. The fully recrystallized structure was also characterized by the “cube” texture (i.e., (001)[100] texture) which has been scarcely reported in polycrystalline bcc metals and alloys. Most of the recrystallized grains with cube orientation appeared in the (001) [100] initially-oriented grains. These features are discussed relative to the inhomogeneous cold-rolled microstructures of columnar crystals.