Alキルド鋼の等温焼鈍中での再結晶過程

抄録

In order to investigate the role of AlN precipitates on the texture development in a low carbon, Al-killed steel, crystallographic orientation dependences of recrystallization and of recovery have been studied during isothermal annealing.
At lower temperatures AlN precipitation occurs at a recovery stage and retards the further evolution of recovery or recrystallization. On the other hand, such a retardation phenomenon does not exist at high temperatures because recrystallization precedes AlN precipitation. The influence of the acid-soluble aluminium content and a reduction in cold rolling on the retardation phenomenon can qualitatively be explained by the changes in the difference of activation energy between recrystallization and AlN precipitation.
There is a crystallographic dependency of recovery rate such that {111}≥{110}>>{100}, and a retardation occurs at an early stage of AlN precipitation. In the case where recrystallization precedes AlN precipitation, the changes in intensity of X-rays diffracted from {hkl} planes are quite similar to those of rimmed steel. On the other hand, characteristic behaviours of Al-killed steel appear when AlN precipitation occurs at the recovery stage. One of them is a marked decrease of {100}-oriented grains during recrystallization. Recrystallization in the {100} grains is suppressed more strongly than the other oriented grains such as the {111} grains, and this decreasing process is carried out by the growth of {111} recrystallized grains into {100} unrecrystallized grains, for example. Another characteristic behavior is the generation of {111} recrystallized grains without a decrease of diffraction intensity and with a small increase in {110} recrystallized grains. Accordingly, it is considered that AlN precipitation at the recovery stage supresses the generation of {110} recrystallized grains from the {111} oriented grains.