Thin Oxide Film Growth during Final Annealing of Stainless Steels

After the cold rolling sequence of the production line,stainless steels strips present highly disordered structure and have to be annealed to recover their crystalline structure.This operation takes place by passing the moving strip through a furnace heated by combustion of natural gas with little air excess.Although the time at high temperature is short(<1 min),the formed surface oxide is thick enough to modify the surface aspect of the steel,making necessary subsequent chemical pickling.The present work explores the oxidation step of various stainless steels during final annealing in order to better understand the mechanisms involved and make further improvements in the pickling sequence.