ABSTRACT
The transformation of inclusions in solid Al-killed steels with different total calcium (T.Ca) contents during the heat treatment process at 1473 K was investigated through laboratory experiments. Calcium aluminate inclusions transformed to Al2O3-CaS during the heat treatment due to reactions between dissolved aluminum and sulfur in the steel matrix and CaO in inclusions. With the T.Ca content in steel reached to 0.003 wt-%, CaO inclusions can hardly transform to CaS inclusions completely due to the insufficient sulfur content. After the heat treatment, the content of CaO in inclusions in steel with 0.0002 wt-% T.Ca was less than 5 wt-%, while it was roughly 30 wt-% with 0.003 wt-% T.Ca in molten steel. The effect of T.Ca content on the transformation of inclusions was calculated using FactSage. Moreover, a kinetic model was developed to predict the transformation of inclusions with different T.Ca contents at heat treatment temperature.
Disclosure statement
No potential conflict of interest was reported by the author(s).