Recrystallization and Related Phenomena. Texture Evolution during Cold Rolling and Recrystallisation of IF Steel with a Strong {111} Hot Band Texture.

Abstract

For a new industrially processed, hot rolled Ti+Nb IF steel, finished in the ferrite region and subsequently annealed, the texture development during cold rolling and annealing is investigated. The strong hot band texture is of the {554} <225> peak type. During cold rolling, the absolute maximum shifts from {554} <225> to {111} <112> along the ε-fibre and the local maximum along the α-fibre shifts from {111} <110> to {223} <110>. During recrystallisation, the weaker α+stronger γ-fibre cold rolling texture is transformed to a very strong γ-fibre annealing texture. Hereby, {111} <110> and, to a much lesser extent, {554} <225> develop at the expense of {111} <112>. Orientation Imaging Microscopy (OIM) reveals that γ-fibre grains nucleate and grow in the beginning of recrystallisation by consuming γ-fibre components of the deformed matrix. Already after 23% recrystallisation, the texture of the recrystallised grains is very similar to the one obtained after full recrystallisation. Moreover, {111} <110> grains are found to be larger and more numerous than {554} <225> grains. The former therefore have an advantage over the latter for consuming the partial α-fibre grains during the final stage of recrystallisation and for further development during grain growth. As a result, a very strong {111} <110> peak type annealing texture is obtained in the present material, resulting in extremely good deep drawability.