Effect of trace Si on MgO·Al_(2)O_(3)inclusion in ultra-low-carbon steel

摘要

There are four types of Mg–Al–Si–O inclusions observed in the Mg-treated Al-deoxidized ultra-low-carbon steel con-taining trace Si,including SiO_(2),2MgO·SiO_(2),3Al_(2)O_(3)·2SiO_(2),and 2MgO·Al_(2)O_(3)·5SiO_(2)and their composite inclusions.Using FactSage,the phase relationship of Mg–Al–Si–O system at 1473–2073 K was calculated using FactSage software,and the change in Si content can change the stable region range of different Mg–Al–Si–O-based inclusions.Based on the types of inclusions observed experimentally,the formation pathways of inclusions were predicted and a kinetic model was established to describe the formation process of the xMgO·yAl_(2)O_(3)–Mg–Al–Si–O and xAl_(2)O_(3)·ySiO_(2)–Mg–Al–Si–O inclusions.