Effect of Annealing on Microstructure and Hardness of Hot and Cold Rolled Zr705

The annealing behaviors of hot and cold rolled Zr705 were investigated in a wide temperature range of 200∼850 °C. Compared to the cold rolled specimens, the hot rolled specimens exhibited lower hardness at temperatures < 500 °C and a shift of the temperature for the maximum hardness to a higher value. Microstructural examination showed that the transformation rate from β to ω phase in the hot rolled specimens was lower than that in the cold rolled specimens. Recovery and recrystallization occurred at a lower temperature in the hot rolled specimens than in the cold rolled specimens. Partial recrystallization occurred in both the specimens at 500 °C, and more recrysatllized grains were observed in the hot rolled specimens. The recrystallization process was completed at 700 °C in both the specimens.