Deep drawable ultra low carbon Ti IF steels hot rolled in the ferrite region

The control of the amount of solute carbon in ultra low carbon Ti IF steels during ferrite rolling and subsequent recrystallization is of prime importance for the development of an appropriate recrystallization texture and for the production of thin deep drawable hot strips. In the present work, the effect of the solute carbon content and the rolling conditions on the recrystallization texture after ferrite rolling and on the corresponding Lankford value was quantified. Therefore, ultra low carbon Ti IF steels with different sulphur and titanium contents were rolled in the ferrite region, in order to obtain a variation in solute carbon content (from 0 to about 10 ppm) at the ferritic rolling temperatures. It was shown that a deep drawing grade (r_mean> 1.4) can be obtained if the chemical composition of the steel guarantees a complete stabilisation of the solute carbon in the austenitic temperature region and if sufficient strain (85%) is given in the finishing train at temperatures lower than about 800°C. It can be concluded that the sulphur and titanium contents have to be chosen slightly higher in comparison to the conventional Ti IF steel grades used for cold rolling and annealing.