Developments in Macro and Micro Texture during Plane Strain Channel Die Compression of IF Steel.

Abstract

Textural developments in plane strain channel die compressed IF (interstitial free) steel were investigated for 7–75% reduction in thickness. Developments in macro texture were investigated by X-ray ODFs (orientation distribution functions) and were simulated by Taylor type models, while actual microtextural developments were studied by OIM (orientation imaging microscopy). Although a gradual increase in α-fiber (RD// ) was observed with increased reductions, γ-fiber (ND// ) increased till 40–50% reduction and then remained almost the same. At the earlier stages of deformation and in general for relatively larger grains, areas around grain boundaries were relatively more deformed (i.e. with more frequent low angle boundaries) and more rotated (as tested in split samples at 7 and 18% reduction) than the grain interior. Till 50% reduction, deformation substructures among deformed grains of different orientations were not significantly different. Above 50% deformation, relatively intense strain localizations (in the form of higher frequencies and larger misorientations of grain boundaries) were observed to form at an angle of about ≈ 37° with RD (rolling direction), somewhat more preferentially in the γ-fiber deformed grains of F {111} and E {111} components. The appearance of such strain localizations increased the stored energies of F/E bands and also possibly accounted for the formation of new high angle boundaries (as evident from increased grain splitting factors).