Abstract：In order to study the aggregation behavior of MgAl2O4 inclusions, single MgAl2O4 inclusions and multi-particle MgAl2O4 inclusions in magnesium-treated aluminum deoxidized mild steel were observed by metallographic sample method and organic solution electrolytic separation method combined with field emission scanning electron microscope. Thermodynamic calculation results indicate that MgAl2O4 inclusions are precipitated in the liquid phase. FactSage calculated the phase transformation law of inclusions in steel, and the predicted types of inclusions were consistent with the experimental observations. The analysis of the multi-particle MgAl2O4 inclusions shows that the cavity bridge force is much greater than the capillary force, van der Waals force, and viscous force. Therefore, the cavity bridge force is the main force that causes the aggregation of MgAl2O4 inclusions. The molten steel condition is that temperature increase and the low aO and low [pct S], cavity bridge force value is small, which causes the weakest aggregation ability of MgAl2O4 inclusions.
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2020, Vol. 55 
