The Transient Evolution of Inclusions in De-Oxidized Fe-Ti-AI-O Melts

摘要

Interstitial free (IF) steel was firstly introduced in Japan in the 70s as a replacement to low carbon steel sheets and since then IF steels have been widely used in automobile applications. This is due to that IF steels offer high formability and non-aging at a low price, IF grade steels are produced by the sequence of (1) decarburization to remove C as much as possible, (2) deoxidation by Al, and finally (3) addition of alloying elements, mainly Ti to bind interstitial elements such as N and C. This is carried out in order to avoid these interstitial atoms from preventing dislocation rearrangement which causes low formability or age-hardening. Steps (2) and (3) are carried out in the ladle.