Mechanism of annealing in interstitial free steels

Annealing behaviour of two high formable ultra low carbon steel grades, IF and IF-HS has been studied using thermoelectric power and resistivity techniques along with conventional methods. The present study points to the fact that, the dominant mode of annealing is recovery, rather than recrystallisation for these steels. Greater degree of deformation results in faster kinetics of recovery in IF and IF-HS steels. Phosphorus does not appear to affect the recovery process, but recrystallisation seems to get sluggish. Resistivity at liquid nitrogen temperature and thermoelectric power at room temperature appear to be effective tools in studying cold rolling and annealing processes of these steels.