Effects of warm rolling on the texture and formability of low carbon and interstitial-free steels

The effect of changing the rolling temperature from the cold range to the warm on the properties of rolled and annealed sheet is far greater in low carbon (LC) than in interstitial-free (IF) steels. The former contain much lower densities of shear bands than the latter, when warm rolled (WR) wider the same conditions. This is attributed to the higher rate sensitivities and other physical properties of the LC grades, which arise, in turn, from the additional dynamic strain aging (DSA) that accompanies an increase in strain rate. The conventional {111} "deep drawing" textures of cold rolled and annealed grades are present after the WR and annealing of IF steels. By contrast, the {111} or ND texture is absent in WR and annealed LC steels. This is attributed to the absence of shear bands in WR LC steels and, therefore, to the absence of the {111} nuclei that form in the vicinity of these bands. Conversely, it is the presence of shear bands in WR IF steels that makes the replacement of cold rolling in these materials possible.