| Abstract Scope |
Nb-microalloying has a significant effect on microstructure evolution during hot rolling. Metallurgical benefits of niobium is associated with the formation of Nb(C,N) in ferrite and austenite, retardation of austenite recrystallization, and further austenite to ferrite phase transformation. Precipitation and microstructure control are therefore important features to achieve better strength and toughness simultaneously. Hot rolling conditions, e.g., temperature, roll force and cooling rate, on strength and toughness is of great interest due to the rolling parameters contribute to strengthening mechanism of micro-alloyed steels. Grain refinement is the most practical way to enhance the niobium-bearing steels by strain-induced precipitation hardening below the non-recrystallization temperature. This rolling research involves residual stress variation associated with parallel-flange section geometry. Therefore, repetitive hardening-softening mechanism could be an important feature to predict the final mechanical properties. Computational and experimental analysis has been used to determine flow stress according to the temperature change in hot rolling. The recrystallization behavior is experimentally observed through the multiple rolling. |