Evolution of Texture at the Initial Stages of Continuous Annealing of Cold Rolled Dual-Phase Steel: Independent of Heating Rate

The performance of cold rolled dual phase (DP) steels depends on their microstructure, which results from the thermomechanical processing conditions, involving hot rolling, cold rolling and continuous annealing. The knowledge on the influence of each annealing stage on the microstructure formation is essential for manufacturing high quality DP steels. In the present work, the effects of some intercritical annealing parameters (heating rate, soaking temperature, and soaking time on the texture and microstructure of a cold rolled DP steel (0.08%C-1.91%Mn) were investigated. The soaking temperature was chosen in a way that all the ferrite got recrystallized before the temperature was reached. The three different heating rates allowed the samples to get recrystallized in three different ways: below Ac1, just around Ac1 and above Ac1. The microstructure of specimens quenched after heating stage and slow cooling stage, simulated on a Gleeble, was analyzed using optical and transmission electron microscopy. {332} fiber texture along with {112}<111> texture component were observed after heating to the soaking temperature as well as after slow cooling. The overall intensity of the texture as well as textural component was observed to be nearly independent of the heating rate as well as cooling rate. The textural evolution was correlated with the volume fractions and morphology of carbides, which depend on the annealing processing parameters