Effect of Alloying Elements (Sb, B) on Recrystallization and Oxidation of Mn-Containing IF Steel

The effects of minor alloying elements (antimony, boron) on the recrystallization and oxidation of Mn-containing interstitial free (IF) steels were investigated using confocal scanning laser microscope (CSLM) under controlled atmosphere of 95% Ar and 5% H-2 (volume percent) at different temperatures. The results indicated that oxidation and recrystallization were primarily controlled by the grain boundaries, which moved due to release of the stored energy or acted as the fast path diffusion of alloying elements. It was found that the addition of antimony suppressed both surface oxidation and internal oxidation, whereas boron addition accelerated surface oxidation but decreased internal oxidation. The reasons caused were that the alloying elements of antimony or boron were known to segregate on the surfaces or grain boundaries to occupy the surface adsorption sites, which were expected to be less catalytic than bare iron on the transportation of alloying elements. The recrystallization was also retarded through adding minor antimony and boron elements. The oxidation kinetics of formation of grain boundary oxides were studied through calculating the areas along grain boundaries, and it was found that the areas parabolically increased with increasing time.