Modification of Inclusions in Molten Steel by Mg-Ca Transfer from Top Slag: Experimental Confirmation of the ‘Refractory-Slag-Metal-Inclusion (ReSMI)’ Multiphase Reaction Model

Shin, Jae Hong; Park, Joo Hyun

doi:10.1007/s11663-017-1080-z

Cited by 44 publications

(40 citation statements)

References 25 publications

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“…The CaO-Al 2 O 3 inclusion is occasionally observed during the secondary refining of Al-killed steel. [1][2][3][4][5][6][7][8] Todoroki et al 1) studied the change in composition of the inclusions in Al-killed 18%Cr-8%Ni stainless steel through a reaction with the top slag of a CaO-Al 2 O 3 -MgO-F system. They found that alumina or MgO•Al 2 O 3 spinel inclusions were formed immediately after the addition of Al.…”

Section: Introductionmentioning

confidence: 99%

“…A similar phenomenon in which an Al 2 O 3 inclusion was changed into a CaO-Al 2 O 3 -type inclusion through a reaction between Al in the steel and the CaO-containing slag has also been observed. [2][3][4][5][6][7] However, because the equilibrium relation with Ca and oxygen differs widely in individual studies, [9][10][11][12][13][14] the most stable oxide in steel containing a small concentration of Ca (few ppm) remains unclear. Harada et al 8)…”

Section: Introductionmentioning

confidence: 99%

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Change in Composition of Inclusions through the Reaction between Al-killed Steel and the Slag of CaO and MgO Saturation

et al. 2019

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The inclusion of CaO-Al 2 O 3 is occasionally observed during the secondary refining of Al-killed steel. In this study, MgO and CaO saturated slag was reacted with Al-killed steel in a MgO crucible, and the dissolution behaviors of Mg and Ca from the slag and the change in composition of inclusions were considered. Both the MgO and CaO in the slag were reduced from the presence of Al in the steel, and the concentration of dissolved Mg and Ca increased with the reaction time and Al concentration. When the Al concentration in the steel was 0.25 mass%, the concentration of dissolved Mg was 30 ppm or higher, whereas that of Ca was only 0.3 ppm. The initial Al 2 O 3 inclusions transformed into a MgO•Al 2 O 3 spinel, and finally changed into MgO inclusions rather than CaO-Al 2 O 3 type inclusions. When the Al concentration was 0.75 mass%, the dissolved Ca concentration increased to 0.9 ppm, and the CaO-Al 2 O 3 type inclusion with MgO was observed at 120 min. When the Al concentration further increased to 2.5 mass%, the concentrations of dissolved Mg and Ca increased to 110 and 3 ppm, respectively. The initial Al 2 O 3 inclusions transformed into MgO inclusions within 5 min, and a CaO-Al 2 O 3-type inclusion with MgO was observed after a 10 min reaction period. Finally, all inclusions transformed into a CaO-Al 2 O 3-type inclusion with MgO at 120 min. KEY WORDS: inclusion; composition change; slag and metal reaction; Al-killed steel; spinel; CaO-Al 2 O 3-MgO inclusion.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Change in Composition of Inclusions through the Reaction between Al-killed Steel and the Slag of CaO and MgO Saturation

et al. 2019

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“…Alternatively, we recently investigated the formation behavior of inclusions as a function of silica content in the slag using a refractory-slag-metal-inclusion (ReSMI) multiphase reaction model. 32,33) It was confirmed that the evolution of inclusions from alumina to spinel and finally to liquid oxide inclusion was promoted by Mg and Ca transfer from slag to molten steel. Also, the starting and finishing points of the modification of spinel into the liquid oxides were delayed as the content of SiO 2 in the ladle slag increased from 7 to 19 wt%.…”

Section: Introductionmentioning

confidence: 87%

Effect of CaO/Al<sub>2</sub>O<sub>3</sub> Ratio of Ladle Slag on Formation Behavior of Inclusions in Mn and V Alloyed Steel

Shin

Park

2018

ISIJ Int.

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The effect of CaO/Al 2 O 3 ( = C/A) ratio of the ladle slag on the formation behavior of non-metallic inclusions in the Mn-V-alloyed steel was investigated using both the experimental method and refractory-slagmetal-inclusion (ReSMI) multiphase reactions simulation. The formation behavior of inclusion was strongly affected by the activity of MgO in the initial slag at the early stage of the reaction. However, since the MgO activity converged to unity due to MgO dissolution from refractory to slag during the reaction, the formation behavior of inclusion was affected by the activity of CaO and Al 2 O 3 in the slag rather than that of MgO at the final stage of the reaction. From the experimental results and ReSMI multiphase reaction model, the formation behavior of inclusions could be divided into three cases according to the C/A ratio of the slag as follows; 1) C/A < 1.5; Alumina → Spinel → Spinel + Liquid oxide, 2) 1.5 < C/A < 2.5; Alumina → Spinel → Liquid oxide, 3) C/A > 3.0; Alumina → Spinel → Liquid oxide → Magnesia. Therefore, it was concluded that the C/A ratio of the ladle slag should be controlled from about 1.5 to 2.5 in order to suppress the harmful solid inclusions such as spinel during secondary refining processes.KEY WORDS: Mn-V-alloyed steel; non-metallic inclusions; secondary refining; ladle slag; refractory-slagmetal-inclusion (ReSMI) multiphase reactions simulation; MgAl 2 O 4 spinel.

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“…Many efforts have been done to optimize steelmaking technologies to control the amount, size, and chemical compositions of non-metallic inclusions in molten steel, such as the formation, [5][6][7][8][9][10][11][12][13] modification, [14][15][16][17][18][19] and removal [20][21][22][23] of inclusions in molten steel. Less attention has been paid to the formation mechanism of oxide inclusions during the solidification of steel.…”

Section: Introductionmentioning

confidence: 99%

The Formation Mechanism of Mn–Al–O Inclusions in Fe–Cr–Mn Stainless Steel during Continuous Casting

Cheng

Li³

et al. 2018

steel research int.

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The formation mechanism of Mn–Al–O inclusions in Fe–Cr–Mn stainless steel during continuous casting is investigated by industrial trials and thermodynamic calculation. The morphology, composition, and size distribution of inclusions in steel specimens are analyzed by scanning electron microscopy and energy dispersive spectroscopy. The main inclusions change from spherical Ca–Si–O and Ca–Si–Mn–O inclusions during LF refining to Mn–Al–O inclusions in continuous casting slab and hot‐rolled sheet. The size of most Mn–Al–O inclusions containing high MnO content is smaller than 4 µm. The formation of these inclusions is consistent with thermodynamic calculation, which indicates that MnO and Al2O3 inclusions are formed during continuous casting process. The calculation results of MnO and Al2O3 inclusions growth shown that the size of MnO inclusion (4 µm) is much larger than that of Al2O3 inclusion (0.4 µm) at the end of solidification, which also accords with the characteristics of inclusions in continuous casting slab and hot‐rolled sheet.

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Modification of Inclusions in Molten Steel by Mg-Ca Transfer from Top Slag: Experimental Confirmation of the ‘Refractory-Slag-Metal-Inclusion (ReSMI)’ Multiphase Reaction Model

Cited by 44 publications

References 25 publications

Change in Composition of Inclusions through the Reaction between Al-killed Steel and the Slag of CaO and MgO Saturation

Change in Composition of Inclusions through the Reaction between Al-killed Steel and the Slag of CaO and MgO Saturation

Effect of CaO/Al<sub>2</sub>O<sub>3</sub> Ratio of Ladle Slag on Formation Behavior of Inclusions in Mn and V Alloyed Steel

The Formation Mechanism of Mn–Al–O Inclusions in Fe–Cr–Mn Stainless Steel during Continuous Casting

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