Texture characteristics of a warm rolled 0.085 wt%-P interstitial free (IF) steel with and without lubrication

Abstract

A 0.085 wt% P micro - alloyed and Ti-stabilized high strength IF (interstitial free) steel was warm rolled under two conditions: One with lubrication and the other without. The results show that lubrication has a significant effect on texture evolution during warm rolling and the subsequent annealing process. Without lubrication, severe shear deformation occurs in the surface layer, which results in recrystallization and the formation of a //ND (normal direction) texture, while the central layer undergoes plane strain deformation and forms a weak //ND deformation texture (typical of bcc iron). With good lubrication, both the surface and central layer experience plane strain deformation and a strong //ND texture is normally formed. The warm rolling texture (which contains both recrystallized and deformed grains) has a profound effect on the subsequent annealing texture. The final textures influence the draw - ability of the plates, i.e. the r - value (r-value: The ratio of the true width strain to the true thickness strain in a sheet tensile test) and |Dr|-value (planar anisotropy coefficient). After annealing, the lubricated plates are characterized by a higher r - value (1.27) and a much lower |Dr|-value (0.075) than those rolled without lubrication (i.e. 0.96 for the r - value and 0.465 for the |Dr|-value).