Formation Mechanism of Oxide-Sulfide Complex Inclusions in High-Sulfur-Containing Steel Melts

Shin, Jae Hong; Park, Joo Hyun

doi:10.1007/s11663-017-1152-0

Cited by 36 publications

(24 citation statements)

References 35 publications

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“…Silicon oxide is the least stable of the analysed oxides and is a common de-oxidation agent. Our samples 15 In our particular case the spinel-type inclusions were found as part of the fractured alumina stringers (the low magnesium content is shown in Figure 6a). Ca is also common and is either the result of Ca modification or slag/melt interaction.…”

Section: Electron Microscopymentioning

confidence: 74%

“…The high oxide number is attributed to the lower oxidation states of the REMs as they form different oxides. 14 Another difference between the REM modified and unmodified inclu- sions is that the oxysulphides in sample 1 (0 μg/g REM) are in fact complex (multi-phase) inclusions, as is common for steels, 15,16 while the REMs form oxysulphide compounds. 14,17 The REM non-metallic inclusions have high atomic numbers Z, so they appear bright in the backscattered electron images.…”

Section: Electron Microscopymentioning

confidence: 99%

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Modification of non-metallic inclusions with rare-earth metals in 50CrMoV13-1 steel

Šuler¹,

Burja²,

Medved³

2019

Mater. Tehnol.

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The potential use of the rare-earth metals in clean steel production was investigated. Reactions between the non-metallic inclusions and the rare-earth metals were investigated in a cold-work tool-steel grade (50CrMoV13-1). A rare-earth metal alloy misch metal (Ce, La, Nd, Pr) was used for the inclusion modification. Aluminium oxide non-metallic inclusions that have a negative effect on the mechanical properties usually occur in the investigated steel. The experimental melts were made in a vacuum induction furnace with different rare-earth metal additions (50, 150, 340, 950 and 2900) ppm. The laboratory cast ingots were hot forged and analysed with light and electron microscopy. It was found that misch metal additions influence the size, composition and type of the non-metallic inclusions in the steel. Most importantly, very small inclusions are formed at lower rare-earth metal additions (up to 340 ppm), but at high additions large non-metallic inclusions are formed (2900 ppm).

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Section: Electron Microscopymentioning

confidence: 74%

Section: Electron Microscopymentioning

confidence: 99%

Modification of non-metallic inclusions with rare-earth metals in 50CrMoV13-1 steel

Šuler¹,

Burja²,

Medved³

2019

Mater. Tehnol.

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“…MnS nucleated around pure oxides and complex oxides-CaS inclusions heterogeneously after about 1350 • C, as illustrated in Figure 10d-f. The calculation of lattice disregistry based on Equation (5) [40] indicated that the disregistry between MgAl 2 O 4 and MnS had the lowest value of 4.1 [15] and that for Al 2 O 3 was 26.9, which facilitated the heterogeneous nucleation of MnS. The formation mechanism of inclusions is illustrated in Figure 10 and different types of inclusions can be explained as following: Figure 10.…”

Section: Formation Mechanism Of Inclusionsmentioning

confidence: 99%

“…Thermodynamic calculations also have been performed to predict the type of calcium aluminates and reliable stability phase diagram of various calcium aluminates were obtained [13]. However, the reactions in the molten steel are complex and inclusions containing CaS would form as the existence of S and CaS inclusions are undeformable [14,15]. Verma and Pistorius et al [16,17] investigated the composition evolution of inclusions in liquid steel modified by calcium and found that CaS may form as an intermediate reaction product, which can subsequently react with Al 2 O 3 to form calcium aluminates as reaction [1].…”

Section: Introductionmentioning

confidence: 99%

“…Sridhar et al [20] observed an inclusion core surrounded by a ring composed of Ca and S. Choudhary et al [21] developed a thermodynamic model for predicting the formation of oxide-sulfide duplex inclusions arising out of competitive reactions between [O], [S], and [Ca] in Al-killed steel. Shin et al [15] discussed the formation mechanism for "spinel + CaS" complex inclusions.…”

Section: Introductionmentioning

confidence: 99%

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Inclusion Characteristics in 95CrMo Steels with Different Calcium and Sulfur Contents

Long

Wang

et al. 2020

Materials

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In order to study the effect of Ca and sulfur contents on the characteristics of inclusions, industrial experiments using 95CrMo steel were conducted. SEM-EDS detections and stereological analysis were used to probe the characteristics of inclusions, including their compositions, morphologies, size, number density, and distribution. The results indicate that there were mainly three types of inclusions in 95CrMo steel billets with 6–18 ppm Ca and 30–100 ppm S: inclusions with single-phased morphology mainly composed of oxides; isolated MnS/CaS-only inclusions; inclusions with multi-phased morphology. The three-dimensional inclusion size distribution suggests that there were more Type-1 inclusions with a small size in low S containing steels. The average diameter of all types of inclusions increased with increasing Ca or S content in 95CrMo steel, indicating that the formation of MnS and CaS coarsened their size. The density distribution of inclusions indicates that the more inclusions there are, the more easily they aggregate and collide. Moreover, it is presumably concluded that the formation of sulfide in the outer layer of oxide inclusions weaken the attraction between oxide inclusions. The equilibrated transformation and formation of inclusions during the cooling process of 95CrMo steel was discussed based on thermodynamic calculation. The equilibrated transformation trajectory of inclusions in 95CrMo steel during the cooling process was Ca2SiO4 + MgO → Ca3MgSi2O8 → Spinel + CaS, which was corresponding to the detected results. The precipitation regular of sulfide was obtained. The formation mechanism for three types of inclusions was discussed.

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Effect of Al on the Solid Reaction between 3CaO·Al₂O₃ Oxide and Fe–S–O–Al Alloy at 1373 K

Wang

Zhang

Ren

et al. 2021

steel research int.

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Diffusion couples of 3CaO•Al 2 O 3 and Fe-S-O-(Al) alloys are prepared to investigate the transformation of calcium aluminate reacting with solid sulfurcontaining alloys. Diffusion behaviors and solid reaction between the alloy phase and the slag phase under 1373 K are studied. Product layers of 12CaO•7Al 2 O 3 and CaS are formed at the interface. After heating for 10 h, the average thickness of CaS layer in samples with and without Al in the alloy phase is 2.10 and 0.71 μm, respectively, while it increases to 3.76 and 1.75 μm after 50 h heating. Aluminum in the alloy makes the solid reaction at the interface easier to happen, meanwhile inhibits the formation of CaS layer by promoting the formation of 12CaO•7Al 2 O 3 layer and suppresses the diffusion of sulfur.

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Formation Mechanism of Oxide-Sulfide Complex Inclusions in High-Sulfur-Containing Steel Melts

Cited by 36 publications

References 35 publications

Modification of non-metallic inclusions with rare-earth metals in 50CrMoV13-1 steel

Modification of non-metallic inclusions with rare-earth metals in 50CrMoV13-1 steel

Inclusion Characteristics in 95CrMo Steels with Different Calcium and Sulfur Contents

Effect of Al on the Solid Reaction between 3CaO·Al₂O₃ Oxide and Fe–S–O–Al Alloy at 1373 K

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Formation Mechanism of Oxide-Sulfide Complex Inclusions in High-Sulfur-Containing Steel Melts

Cited by 36 publications

References 35 publications

Modification of non-metallic inclusions with rare-earth metals in 50CrMoV13-1 steel

Modification of non-metallic inclusions with rare-earth metals in 50CrMoV13-1 steel

Inclusion Characteristics in 95CrMo Steels with Different Calcium and Sulfur Contents

Effect of Al on the Solid Reaction between 3CaO·Al2O3 Oxide and Fe–S–O–Al Alloy at 1373 K

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Effect of Al on the Solid Reaction between 3CaO·Al₂O₃ Oxide and Fe–S–O–Al Alloy at 1373 K