Texture Development in Low Carbon Sheet Steels for Automotive Application

Abstract

The development of recrystallization texture in three low carbon sheet steels, conventional IF steel, fine grained IF steel, and DP steel, for automotive application was investigated using EBSD technique. The recrystallization texture at the early stage of recrystallization was very similar to that at the final stage in all three steels. A strong α-fiber texture with {112} peak and weaker γ-fiber texture with {111} peak were developed during the deformation of all three low carbon steels. After recrystallization, they changed to a strong γ-fiber texture with strong {111} component. However, the intensity of the texture components varied in the different steels. The grains of γ-fiber orientations developed from deformed grains of similar orientations and grew rapidly, consuming the neighboring grains to form a strong γ-fiber texture. In conventional IF steels, some recrystallized grains formed at grain boundaries showed weak correlation with {111} orientation, however, the growth rates of these random grains were too slow to affect the final recrystallization texture. In the fine grained IF steel, the intensity of the {001} component after recrystallization was higher than that in the conventional IF steel. Strain induced boundary migration (SIBM) was observed in the fine grained IF steel. The intensity of the γ-fiber texture was much weaker in the DP steel than in the IF steels. Nucleation of the {110} and {001} recrystallized grains from the shear bands in {111} or {110} grains was expected. The austenite transformation during the intercritical annealing of the DP steel was found to have little effect on the formation of its final recrystallization texture.