The effect of three heat processes with different calcium contents on the evolution of inclusions during the ladle furnace refining process of AISI 321 stainless steel was investigated.The size,morphology,and composit...The effect of three heat processes with different calcium contents on the evolution of inclusions during the ladle furnace refining process of AISI 321 stainless steel was investigated.The size,morphology,and composition of the inclusions were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy.After the addition of aluminum and titanium,the primary oxide in the AISI 321 stainless steel was an AbOs—MgO—TiOx complex oxide,in which the mass ratio of AbOs/MgO was highly consistent with spinel(MgO・AbO3).After calcium treatment,the calcium content in the oxide increased significantly.Thermodynamic calculations show that when the Ti content was 0.2wt%,the Al and Ca contents were less than 0.10wt%and 0.0005wt%,respectively,which was beneficial for the formation of liquid inclusions in molten steel.Moreover,the modification mechanism of calcium on TiN-wrapped oxides in combination with temperature changes was discussed.展开更多
To avoid the volume expansion of basic oxygen furnace (BOF) slag for use in building materials, a hot slag modification process was proposed to reduce free CaO (f-CaO) in the molten slag. A transient 3D numerical mode...To avoid the volume expansion of basic oxygen furnace (BOF) slag for use in building materials, a hot slag modification process was proposed to reduce free CaO (f-CaO) in the molten slag. A transient 3D numerical model of BOF molten slag modification by SiO_(2) particles was established. The flow and heat transfer of molten slag, movement and dissolution of the modifier, and concentration distribution of f-CaO in slag during the modification of BOF were studied. The distribution of f-CaO concentration is inhomogeneous all over the molten slag. The mixing effect at the slag surface is weaker than that at the half-height plane of the slag. To consume the f-CaO below 2.0 wt.% in the slag, the optimum quantity of the SiO_(2) modifier is 10.0% of the mass of the slag. The fine SiO_(2) particles help attain a lower final mass fraction of f-CaO and a higher SiO_(2) utilization ratio.展开更多
基金supported by the State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,China.
文摘The effect of three heat processes with different calcium contents on the evolution of inclusions during the ladle furnace refining process of AISI 321 stainless steel was investigated.The size,morphology,and composition of the inclusions were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy.After the addition of aluminum and titanium,the primary oxide in the AISI 321 stainless steel was an AbOs—MgO—TiOx complex oxide,in which the mass ratio of AbOs/MgO was highly consistent with spinel(MgO・AbO3).After calcium treatment,the calcium content in the oxide increased significantly.Thermodynamic calculations show that when the Ti content was 0.2wt%,the Al and Ca contents were less than 0.10wt%and 0.0005wt%,respectively,which was beneficial for the formation of liquid inclusions in molten steel.Moreover,the modification mechanism of calcium on TiN-wrapped oxides in combination with temperature changes was discussed.
基金the National Natural Science Foundation of China(Grant Nos.U1860205 and 52204352)Young Elite Scientist Sponsorship Program by China Association for Science and Technology(Grant No.YESS20200210)Youth Project of Hubei Natural Science Foundation(Grant No.2022CFB593).
文摘To avoid the volume expansion of basic oxygen furnace (BOF) slag for use in building materials, a hot slag modification process was proposed to reduce free CaO (f-CaO) in the molten slag. A transient 3D numerical model of BOF molten slag modification by SiO_(2) particles was established. The flow and heat transfer of molten slag, movement and dissolution of the modifier, and concentration distribution of f-CaO in slag during the modification of BOF were studied. The distribution of f-CaO concentration is inhomogeneous all over the molten slag. The mixing effect at the slag surface is weaker than that at the half-height plane of the slag. To consume the f-CaO below 2.0 wt.% in the slag, the optimum quantity of the SiO_(2) modifier is 10.0% of the mass of the slag. The fine SiO_(2) particles help attain a lower final mass fraction of f-CaO and a higher SiO_(2) utilization ratio.
