LAUSR

Abstract Recrystallization is important for steel processing because it modifies microstructure along the process route and thus determines the final properties of steel products. Loads in various deformation operations and consistency of dimensions and shape of deformed steels are also influenced by recrystallization and its homogeneity. These factors are especially important in hot rolling that aims at uniform refined hot rolled microstructure. This can be achieved by avoiding dynamic recrystallization (DRX) of austenite during hot rolling passes and static recrystallization between them and before cooling. Alternatively, microstructure can be refined by stimulating recrystallization. Experimental data and constitutive analysis show that for a given steel there exist two limiting values of Zener-Hollomon parameter Z that delineate three temperature – strain ranges for DRX: no-DRX range (high Z) where DRX cannot be initiated irrespective of the applied strain, full DRX range (low Z) and partial DRX range (intermediate Z). Avoiding DRX in finishing rolling sequence implies setting up rolling speeds and temperatures in no-DRX range of Z. Alternatively, for roughing sequence the mill settings should be such as to keep rolling speeds and temperatures in the full DRX range. In any case it is imperative to avoid partial DRX, i.e., to avoid rolling speeds and temperatures that correspond to intermediate Z range. This approach can be directly utilized to control DRX in hot strip mills and plate mills based on the experimental data.