The Morphology and Chemistry Evolution of Inclusions in Fe-Si-Al-O Melts

Kwon, Youjong; Choi, Ju-Han; Sridhar, Seetharaman

doi:10.1007/s11663-011-9523-4

Cited by 14 publications

(5 citation statements)

References 13 publications

(28 reference statements)

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“…No silica inclusion or Si‐bearing inclusions was found. According to a research from the literature (laboratory experimental work), the dominant kind of inclusion depends on the order of deoxidant addition. For example, when Al and Si are used as deoxidants, if aluminum is added before silicon, silicon oxide and aluminum oxide are found.…”

Section: Resultsmentioning

confidence: 99%

Castability and Inclusions in a Low Sulfur Ca‐Treated Peritectic Steel for Two Deoxidation Techniques

Leão

Klug

Carneiro

et al. 2019

steel research int.

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Liquid inclusions are important to avoid nozzle clogging during continuous casting of steel. To minimize clogging tendency at a Brazilian steelworks for a low‐sulphur Ca‐treated peritectic steel, deoxidation technique is changed from only Al addition as deoxidant to Fe–Si ferroalloy followed by Al addition, reducing the amount of Al by 20 wt%. Calcium treatment procedure is not changed. According to steelworks data, clogging occurrences are drastically reduced with this process change. In this context, quenched steel samples are collected from the tundish before and after the aforementioned process change. Nonmetallic inclusions characterization is manually performed using scanning electron microscope. For both conditions—before and after the industrial process changes—the inclusions are typically globular ones. However, before the changes, the inclusion modification is not complete because the core of the inclusions is composed by polygonal spinel. After the changes, the inclusions become homogeneous. Computational thermodynamics is applied to calculate the castability windows; they show that the amount of calcium dissolved in liquid steel is too low before the process changes, and this fact explains the blockage of the tundish nozzles, which is observed at steelworks, due to the deposition of high melting point spinel inclusions.

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Section: Resultsmentioning

confidence: 99%

Castability and Inclusions in a Low Sulfur Ca‐Treated Peritectic Steel for Two Deoxidation Techniques

Leão

Klug

Carneiro

et al. 2019

steel research int.

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“…In many cases, the behaviour of inclusions in steel melt depends on the sequence of alloy addition. [40] One production route of ultra-low carbon steel can be taken as an example, [41] at which various ferroalloys can be added into the steel during different stages of ladle treatment after tapping from the converter, as shown in Figure 5. In this process, FeP is usually added before deoxidation which is performed at stages 1 and 3 of the ladle refining.…”

Section: Impurities In Ferroalloys and Behaviour Of Nmi From Ferroalloys In The Steel Meltmentioning

confidence: 99%

Non-metallic Inclusions in Different Ferroalloys and Their Effect on the Steel Quality: A Review

Wang

Karasev

Park

et al. 2021

Metall Mater Trans B

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Ferroalloys have become increasingly important due to their indispensable role in steelmaking. In addition, the demand for improved steel qualities has increased considerably, which in turn highlights the quality of ferroalloys. This is due to the fact that the impurities in ferroalloys directly and significantly influence the quality of steel products. To gain a better understanding of the main trace elements and inclusions in ferroalloys (such as FeSi, FeMn, SiMn, FeTi, FeCr, FeMo, FeNb, FeV, FeB, some complex ferroalloys) and their behaviours in steel melt after the additions of these ferroalloys, information from a large number of previous results on this topic was extensively reviewed in this work. The applications of different ferroalloys and their production trends were discussed. In addition, the effects of some trace element impurities from ferroalloys on the inclusion characteristics in steel were also discussed. The possible harmful inclusions in different ferroalloys were identified. Overall, the results showed that the inclusions present in ferroalloys had the following influence on the final steel cleanliness: (1) MnO, MnS and MnO–SiO2–MnS inclusions from FeMn and SiMn alloys have a temporary influence on the steel quality; (2) the effect of large size SiO2 inclusions (up to 200 μm) in FeSi and FeMo alloys on the steel cleanliness is not fully understood. The effect of Al, Ca contents should be considered before the addition of FeSi alloys. In addition, Al2O3 inclusions and relatively high Al content are commonly found in FeTi, FeNb and FeV alloys due to their production process. This information should be paid more attention to when these ferroalloys are added to steel; (3) except for the existing inclusions in these alloys, the Ti-rich, Nb-rich, V-rich carbides and nitrides, which have important effects on the steel properties also should be studied further; and (4) specific alloys containing REM oxides, Cr–C–N, Cr–Mn–O, Al2O3, Al–Ti–O, TiS and Ti(C, N) have not been studied enough to enable a judgement on their influence on the steel cleanliness. Finally, some suggestions were given for further studies for the development of ferroalloy productions.

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“…7,8) In addition, Si/Al complex deoxidation process has been widely used, in which case the composite oxides with different contents of (SiO 2 ) and (Al 2 O 3 ) are easy to be formed. [9][10][11] In a word, the deoxidization treatment determines the type of deoxidized products. Rare earth (RE) elements have been widely used in high-quality steel to improve the heat resistance, corrosion resistance, and mechanical properties of products, [12][13][14][15] which is usually added after deoxidization of molten steel.…”

Section: Introductionmentioning

confidence: 99%

Agglomeration Characteristics of Various Oxide Inclusions in Molten Steel Containing Rare Earth Element under Different Deoxidation Conditions

Wang

Liu

2021

ISIJ Int.

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Comprehensive investigation of agglomeration behavior of oxide inclusions in steel-containing rare earth (RE) under different deoxidation conditions is essential for improving the nozzle-clogging problem during continuous casting. The present study first optimized the thermodynamic model by supplementing thermodynamic data of the RE-compound to study the formation of various inclusions in the Ce-Si-Al-O system. On this basis, laboratory-scale experiments with different deoxidation conditions were designed to obtain samples containing one single type of inclusions, viz., SiO 2 , SiO 2 -Ce 2 O 3 or SiO 2 -Al 2 O 3 -Ce 2 O 3 , respectively. Subsequently, the agglomeration behavior of inclusions was observed in situ by confocal laser scanning microscopy (CLSM), and the corresponding attractive forces were calculated to compare the agglomeration tendency of various inclusions. The results indicate that, in the Si deoxidized samples, SiO 2 -Ce 2 O 3 inclusions agglomerate to form clusters with the attractive force of 4.3 × 10 − 17 N to 4.2 × 10 − 15 N, which is weaker than that of Al 2 O 3 and Al 2 O 3 -Ce 2 O 3 inclusions after Al deoxidation. Although SiO 2 inclusions can agglomerate, their attractive force is only 6.3 × 10 − 19 N to 1.2 × 10 − 16 N, which is the weakest of the above inclusions. In the case of Si/Al complex deoxidization, spherical SiO 2 -Al 2 O 3 -Ce 2 O 3 liquid inclusions are formed after Ce treatment, and no agglomeration of such inclusions was observed in situ. The study could provide theoretical guidance for improving the nozzle-clogging problem of RE-containing steel from inclusion-controlling perspective under different deoxidation conditions.

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The Morphology and Chemistry Evolution of Inclusions in Fe-Si-Al-O Melts

Cited by 14 publications

References 13 publications

Castability and Inclusions in a Low Sulfur Ca‐Treated Peritectic Steel for Two Deoxidation Techniques

Castability and Inclusions in a Low Sulfur Ca‐Treated Peritectic Steel for Two Deoxidation Techniques

Non-metallic Inclusions in Different Ferroalloys and Their Effect on the Steel Quality: A Review

Agglomeration Characteristics of Various Oxide Inclusions in Molten Steel Containing Rare Earth Element under Different Deoxidation Conditions

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