The evolution of inclusions that contain Al, Mg, and Ti was studied through industrial-grade experiments. Field emission scanning electron microscopy, energy dispersive spectrometry,
inductively coupled plasma atomic emission spectrometry, and FactSage software were used to analyze the evolution mechanisms of inclusions in
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The evolution of inclusions that contain Al, Mg, and Ti was studied through industrial-grade experiments. Field emission scanning electron microscopy, energy dispersive spectrometry,
inductively coupled plasma atomic emission spectrometry, and FactSage software were used to analyze the evolution mechanisms of inclusions in Al-killed titanium alloyed interstitial free (IF) steel. The research found that the evolution of inclusions during the smelting process of IF steel is results in ‘
large sphere-like SiO2-CaO-FeO-MgO-MnO’ and ‘small cluster spherical FeO-MnO’ change to cluster-like Al
2O
3 and irregular MgO·Al
2O
3, then change to Al
2O
3·TiO
x and Al
2O
3, and finally change to Al
2O
3. It is difficult for Al
2O
3·TiO
x to stably exist in the IF molten steel. It is the key to extend the holding time properly after Ruhrstahl Heraeus (RH) to ensure the removal of Al
2O
3 inclusion. With the increase of Mg content, the change path of MgAl
2O
4 inclusion in IF steel is that Al
2O
3 changes to MgO·Al
2O
3, and finally changes to MgO. It is difficult to suppress MgO·Al
2O
3 spinel formation by controlling the oxygen in the steel, but Ca can modify part of the MgO·Al
2O
3 spinel inclusions during RH refining. In order to ensure the removal of 6–10 μm inclusions, the holding time is suitable for 19–42 min.
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