Texture development in cold rolled and annealed C-Mn-Siand C-Mn-Al-SiTRIPsteels

The texture of two transformation induced plasticity steels has been studie d by means of crystallographic orientation mapping. Texture measurements we re carried out on ferrite, bainite, and austenite. The polygonal ferrite an d the bainite texture, both bee, could be distinguished based on the image quality parameter of the electron backscattering diffraction measurement. B oth bee textures were very similar, the main difference being the more pron ounced < 111 > (alpha) \ \ ND (ND=normal direction) and < 110 > (alpha) \ \ RD (RD=rolling direction) fibre textures in the polygonal ferrite. The fee texture was a strong gamma deformation texture, characterised by the beta fibre. The presence of the alpha fibre confirmed the strong < 110 > (gamma) \ \ ND direction, which was previously detected by means of X ray diffract ion (XRD). The measured fee and bee textures were used to calculate orienta tion distribution function transformations according the Bain, Kurdjumov-Sa chs, and Nishiyama-Wasserman orientation relationships. The predicted cube component {001}(gamma) < 100 > (gamma), which was missing in the measured t exture, of gamma (ret) indicates a variant selection for the gamma --> alph a (B) transformation. In addition it was shown that crystallographic orient ation mapping could be used to make reliable phase fraction determinations, which were previously based on the light optical microscopy of colour etch ed specimens. This also proves that XRD determination of gamma (ret) is fla wed owing to the strong texturing of all phases present in the microstructu re.