Effect of Slag Protection System and Sample Geometry on Homogeneity of Total Oxygen Content in Samples from Liquid Steel

Ericsson, Ola; Karasev, Andrey; Jönsson, Pär G.

doi:10.1002/srin.201000136

Cited by 10 publications

(10 citation statements)

References 6 publications

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“…Specimens of molten steel and top slag were taken with pail samplers at the AOD-end of every heat, LF-start, after calcium-treatment, tundish and mold. The distribution of non-metallic inclusions in different positions into the samples can be heterogeneous, as was reported in some articles [20][21]. Therefore, the same positions into the samples were selected for analysising.…”

Section: Sampling and Analysis Approachmentioning

confidence: 99%

Thermodynamics and transient behavior of the inclusion in Si deoxidized stainless steel for high-grade plate

Wang

Xue

Zhang

et al. 2019

Metall. Res. Technol.

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The experiments were carried out to determine the transient behavior of the inclusion in Si-deoxidized stainless steel for high-grade plate. The samples were taken from three heats of the steel during the whole production process from the AOD to the mold, which were subsequently examined by an automatic scanning electron microscope with field energy dispersive spectrometer (FE-SEM&EDS). It can be summarized that appropriate calcium treatment intensity could modify inclusions into liquid ones. Excessive calcium treatment above ([Ca] = 25 ppm) will increase the melting point of the inclusions, which cannot keep in the liquid region at the solidification temperature. Therefore, the calcium addition in Si-deoxidized stainless steels should be controlled to a relatively lower value ([Ca] = 10 ppm). In addition, the content of aluminum in steel also has an important influence on the control of inclusion. When the content of aluminum ([Al] = 0.012%) is too high, the inclusions in steel are difficult to be controlled within the liquid phase. The chemical evolution of the inclusions in steel at high temperature and during solidification process were comprehensively calculated, considering all types of inclusions such as calcium oxide, aluminum oxide, silicon oxide, calcium aluminate, calcium silicate, mullite, and liquid inclusion. The thermodynamic calculations are in good agreement with experimental results, which can predict the formation of the inclusions in Si-deoxidized stainless steels.

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Section: Sampling and Analysis Approachmentioning

confidence: 99%

Thermodynamics and transient behavior of the inclusion in Si deoxidized stainless steel for high-grade plate

Wang

Xue

Zhang

et al. 2019

Metall. Res. Technol.

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“…In the last decades, several methods of offline investigations, such as light optical microscopy (LOM), scanning electron microscopy (SEM), the automatic software INCA-Feature and ASPEX, chemical extraction (CE), and electrolytic extraction (EE), have been developed to study the characteristics of NMIs. [1][2][3][4][5][6][7][8][9] However, the investigation results could only be obtained after several hours, days, or even months. It means that no efforts could be made online directly during the process, based on the investigation results.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Nonmetallic Inclusions in Low‐Alloyed Steels Using Pulse Distribution Analysis Optical Emission Spectroscopy and Offline Investigation Methods

Yang

Karasev

et al. 2021

steel research int.

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The characteristics of nonmetallic inclusions (NMIs) in low-alloyed steel samples taken during ladle treatment before and after Ca treatment are evaluated using the pulse distribution analysis optical emission spectroscopy (PDA/OES) method, INCA-Feature investigations of inclusions on a polished surface of steel samples, and 3D investigations of NMIs after electrolytic extraction (EE) of steel samples. The investigation results of NMIs using the different methods were compared. The PDA/OES results show a clear tendency of a change in the average composition and quantity of NMIs during ladle treatment, which correlates well with the results obtained from the other two methods. Overall, it is found that the application of the PDA/OES method is appropriate to enable a fast online evaluation of inclusion compositions and their behaviors during steelmaking. This, in turn, provides the means for establishing an online control and correction of technological operations of the ladle treatment to implement necessary modification of NMIs to improve the cleanliness of steels and avoid clogging problems during casting.

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“…Since then our group has carried out many studies focusing on determining how the inclusion characteristics vary during ladle treatment, based on plant trials [2][3][4][5][6]. Plant trials have also been made to study the following aspects of ladle refining operations: i) the effect of deoxidation praxis and ferroalloy additions on the inclusion characteristics [7][8][9], ii) the influence of the slag on the inclusion characteristics and sulphur content [10][11][12][13], iii) the influence of stirring on the inclusion characteristics [14][15][16][17] and the influence of sampling on determining the inclusion characteristics in process samples [18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

The role of process control on the steel cleanliness

Steneholm¹,

Andersson

Tilliander

et al. 2016

Ironmaking & Steelmaking

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The possibilities of obtaining a good process control in order to reach a good cleanliness of the steel were studied based on plant trials. Steel and slag samples were taken from two steel grades with a slightly different composition, but with similar processing conditions. Thereafter, the chemical compositions of the steel and slag samples were determined. The results show that the sum of the FeO and MnO was found to be a clear indicator for when reoxidation had taken place. No conclusive indicator was found to predict the extent of slag carry-over from the electric arc furnace. However, most of the variation in deoxidation seem to originate from the accuracy of the slag raking. Steel grades with low amounts of deoxidisers such as C and Si naturally were found to result in higher oxygen contents at the start of deoxidation. Furthermore, calculations of oxygen activities in the steel melt were made and the results were compared to measurements with varying results. Overall, the results indicate that calculation of oxygen activities with multivalence slag species such as Fe and Cr requires additional measurements to obtain accurate results.

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Effect of Slag Protection System and Sample Geometry on Homogeneity of Total Oxygen Content in Samples from Liquid Steel

Cited by 10 publications

References 6 publications

Thermodynamics and transient behavior of the inclusion in Si deoxidized stainless steel for high-grade plate

Thermodynamics and transient behavior of the inclusion in Si deoxidized stainless steel for high-grade plate

Characterization of Nonmetallic Inclusions in Low‐Alloyed Steels Using Pulse Distribution Analysis Optical Emission Spectroscopy and Offline Investigation Methods

The role of process control on the steel cleanliness

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