Effects of Two-Step Cold Rolling on Recrystallization Behaviors in ODS Ferritic Steel

Abstract

The recrystallization behaviors of Fe–15Cr ODS ferritic steels underwent two different processing routes were compared; (a) 1st 70% cold rolling + intermediate annealing, (b) 1st 70% cold rolling + intermediate annealing at 1100°C to make a recrystallization structure +2nd 70% cold rolling + final annealing. Hardness and texture changes during rolling and isochronal annealing were investigated. Results show that the recrystallization temperature of 70% cold rolled specimen is 950°C and the recrystallization texture is {111}<112>. On the contrary, in the case of specimen which was cold rolled for two times, the recrystallization temperature increases to 1100°C, and the recrystallization texture changes to {111}<110>. These changes are ascribed to the different routes of crystalline rotation during 1st and 2nd cold rolling, which produce different cold rolling texture. Higher {100}<110> content induced by 2nd cold rolling after intermediate recrystallization which has low stored energy increases the recrystallization temperature. And the difference in texture intensity along γ fibre after 1st and 2nd cold rolling results in different recrystallization texture.