Effects of Rolling Reduction and Annealing Temperature on the Recrystallization Structure of Solidified Columnar Crystals in a 19% Cr Ferritic Stainless Steel

The cold-rolling and recrystallization behavior of solidified columnar crystals in a 19% Cr ferritic stainless steel has been investigated. As the rolling reduction increased, the recrystallization rate increased and the recrystallized grain size decreased. However, the (001)[110] initially-oriented columnar grains were hard to recrystallize without regard to rolling reduction so that the recrystallization structure was very inhomogeneous in grain size even in a heavily-rolled (90% rolled) specimen. The recrystallization rate of 70% rolled specimens increased as the annealing temperature increased. In particular, at the temperatures where carbides did not precipitate the recrystallization rapidly completed and a coarse-grained structure formed in a short time annealing because of rapid grain growth. As a result, in the Fe-19% Cr ferritic columnar crystals a favorable recrystallization structure with fine and uniform grain size cannot be obtained simply by increasing rolling reduction or by controlling annealing temperature.