Bainite transformation during continuous cooling of low carbon microalloyed steel

The evolution of the final microstructure for a low carbon Nb-Ti microalloy ed plate steel was studied during a simulation of thermomechanical processi ng for hot rolling following by accelerated cooling. The effects of austeni te deformation below the non-recrystallisation temperature T-NR, cooling ra te, and interrupt temperature on the formation of conventional (intergranul ar) bainite (CB), acicular ferrite (intragranular) (AF), and martensite-aus tenite (MA) constituents were determined. With increases in austenite defor mation and cooling rate, and decrease in the interrupt temperature, the fin al microstructure changed From a mixture of CB-CMA through CB + AF + MA to a dual phase AF + MA.