Effect of cold rolling and mode of annealing on textures, mechanical properties and formability limit diagrams in interstitial free steel sheets

Formability limit diagram (FLD) and strain limits are determined along with mechanical properties and the same are correlated with textural characterization as a function of degree of rolling in an interstitial free (IF) steel. Around 65-70% and 85-90% hot deformation were given in austenitic region. It was found that 85-90% deformation developed strong hot band texture and the texture was dominated by {112}< 110 > and {332}< 113 > orientations. Hot rolled steel sheets were then cold rolled to 50%, 70%, 80% and 90%, where the perfect alpha-fiber and gamma-fiber textures were developed at 80% cold reduction. Excellent formability was obtained by batch as well as continuous mode of annealing. The new gamma-fibers were developed after annealing. It was observed that IF steel sheet has to be cold rolled between 80% and 90%. From FLD plots, it was observed that IF steel sheets were highly formable.