Effect of Nitrogen Content on Deep Drawability of Rimmed Low Carbon Cold Rolled Steel Sheet

Abstract

In the production of rimmed steel sheet, its nitrogen content converged to a constant level at box annealing process. Therefore increased nitrogen in steel making did not affect the strain aging properties of the sheet, but deteriorated the drawability or the r-value of the sheet.
To clarify the effect of nitrogen on recrystallization texture formation, the nitrogen content at cold rolling and that at recrystallization annealing were varied by atmospheric reaction at 350-400°C after cold rolling and then recrystallization textures were compared. Amounts of {111} and {110} components of the recrystallization texture were markedly affected by the nitrogen content at annealing, whereas they were not affected by that at cold rolling. Meanwhile, neither the amount of {100} component nor recrystallized grain size was influenced by nitrogen content.
It was supposed that high nitrogen content at the ladle in steel making induced larger amounts of nitrogen atoms as interstitials at recovery or recrystallization stage of the cold rolled steel, which promoted the recrystallization of {110} component and suppressed the development of {111} component at recrystallization annealing.