Effect of hot-band annealing condition on secondary recrystallization of ultra-low carbon 2.3%Si-1.7%Mn steel

The effect of hot-band annealing temperature on secondary recrystallization was investigated using the hot-rolled steel sheets containing 2.3%Si-1.7%Mn-0.01%sol.Al of 2.3 mm thick. The followings were found and concluded. (1) Grain growth behavior in final annealing was strongly affected by the hot-band annealing condition. Namely it was considered to depend on the heterogenous microstructure along the thickness direction after hot-band annealing. (2) When the hot-band did not recrystallize after the hot-band annealing, secondary recrystallization did not occur. On the other hand, secondary recrystallization was evolved completely and magnetic induction B8 indicated the highest value when only near surface layer of hot-band recrystallized after the hot-band annealing. However, fully recrystallized hot-band led to imperfect secondary recrystallization and lower B8 value.