Synergistic Effects of Crucibles and Low‐Basicity Refining Slag on Inclusions in Si‐Mn Killed Steel

To explore the synergistic effect and mechanism of crucibles and low basicity refining slag on inclusions in silicon‐manganese (Si‐Mn) killed steel, four crucibles were used to smelt Si‐Mn killed steel. The effects of different crucibles on inclusions and the corrosion resistance of molten steel/refining slag were investigated by SEM‐EDS, an inclusion of an automatic analysis system, and other equipment. The results show that the use of an MgO crucible is more conducive to the control of the size and quantity of inclusions. The Al 2 O 3 and MgO–MgAl 2 O 4 crucibles cause the proportion of Al 2 O 3 in inclusions to substantially increase. The inclusions in the steel using the ZrO 2 crucible are mainly composite inclusions containing ZrO 2 as the core and SiO 2 –MnO–Al 2 O 3 as the outer layer. In terms of the erosion resistance of molten steel, ZrO 2 crucible shows the lowest erosion degree. MgO crucible reduces further erosion of molten steel owing to the formation of a dense reaction layer. In terms of resistance to refining slag erosion, ZrO 2 crucible has better performance. An Al‐containing crucible is not suitable for smelting Si‐Mn killed steel, whereas ZrO 2 crucible is suitable for smelting Si‐Mn killed steel. MgO crucible can also be used as an economical and reliable crucible for smelting Si‐Mn killed steel.