Formation of CaO•TiO2-MgO•Al2O3 dual phase inclusion in Ti stabilized stainless steel

The formation of CaO center dot TiO(2)-MgO center dot Al(2)O(3) dual phase inclusion in 321 stainless steel was investigated in the laboratory. The result indicated that the condition for the formation of CaO center dot TiO(2)-MgO-Al(2)O(3) in 321 steel is [Ca]> 0.001wt%, [Ti]> 0.1 wt%, and [Al] > 0.01 wt%. The mechanism is the following: Al(2)O(3) inclusion turns into CaO-Al(2)O(3) after Ca-Si wire is fed into the molten steel; [Mg] is then obtained by reducing MgO in slag or crucible wall by [Al] and [Ti]; finally CaO-Al(2)O(3) inclusion is changed into CaO center dot TiO(2)-MgO center dot Al(2)O(3) by the reaction with [Mg], [Ti], and [O] in the molten steel simultaneously.