Fostering deep drawability through recrystallization texture strengthening in aluminum-rich interstitial free steel

Abstract

The development of strong normal direction (ND)║〈111〉 fiber texture is crucial for deep drawability in interstitial free steels used for automotive applications. The present work focuses on comparative investigations on texture development, Lankford parameter measurement, microstructural evolution, recrystallization kinetics, and grain growth kinetics of titanium‑niobium stabilized interstitial free steels with different aluminum (Al) content. Industrially hot-rolled interstitial free steels with 0.06 wt% Al and 0.17 wt% Al were cold-rolled (∼90%), followed by isothermal annealing at 650 °C, 675 °C, and 700 °C for various time intervals. Texture studies using electron backscatter diffraction and X-ray diffraction showed the formation of a stronger ND fiber texture in 0.17 wt% Al steel compared to 0.06 wt% Al Steel after full recrystallization. A high r m value in 0.17 wt% Al steel than in 0.06 wt% Al Steel indicates the beneficial effects of Al addition in interstitial free steel. The study of recrystallization kinetics depicted faster recrystallization kinetics in interstitial free steel with 0.17 wt% Al. The grain growth kinetics of recrystallized grains illustrated similar behavior in both steels. At the onset of recrystallization in 0.06 wt% Al steel, a transient strengthening of the {001} 〈110〉 component (an effect of stress-induced boundary migration) was observed, which obstructed the nucleation of ND fiber grains. In contrast, the initial rapid nucleation of ND fiber grains in the 0.17 wt% Al steel was responsible for stronger ND fiber texture development. • Aluminum-interstitial-free steel developed stronger {111} <uvw> fiber texture. • Aluminum-interstitial-free steel showed high r m value. • Aluminum-interstitial-free steel possesses faster recrystallization kinetics. • Strain-induced boundary migration is dominant initially in normal interstitial free steel. • Rapid nucleation of {111} <uvw> grains occurs in Aluminum-interstitial free steel.