Recrystallization of a Cold Rolled Trip-assisted Steel during Reheating for Intercritical Annealling.

Abstract

A TRIP-assisted steel, with a conventional composition containing 0.11% C, 1.53% Mn and 1.26% Si, and a hot band microstructure composed of ferrite, martensite and carbide particles, was cold rolled with a reduction of 70%. Partially recrystallized samples were obtained by water quenching the cold rolled sheets which were reheated at a constant rate of 10°C/s to temperatures in the range between 525°C (A_c3). It was demonstrated that the recovery and recrystallization behaviour was critically controlled by the carbide formation and growth during the initial stages of the annealing treatment. No interaction was observed between recrystallization and transformation phenomena as the static recrystallization was already completely finished before the start of the α→γ phase transformation. The microtexture observations obtained by orientation imaging microscopy have revealed that the //ND fibre which dominates the annealing texture at the end of the static recrystallization already starts to develop at the initial nucleation stage. The {111} fibre component which is slightly favoured in the recrystallization texture together with other less common BCC annealing components quickly disappear from the ferrite texture after the start of the phase transformation, which could be related to the preferential presence of redissolving carbide particles in these components.