Magnesium Non-metallic Inclusions in Non-oriented Electrical Steel Sheets

Petrovič, Darja Steiner; Arh, B.; Tehovnik, Franc; Pirnat, Miran

doi:10.2355/isijinternational.51.2069

Cited by 11 publications

(8 citation statements)

References 37 publications

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“…This steel is broadly comparable (lower in Al, higher in Si) to the NGO electrical steels for which Steiner Petrovic et al 3) reported highly unusual Mg-rich NMI. The production of this type of steel involves alloying of large amounts of FeSi and Al-wire additives and it is well known that the obtained steel melts can be difficult to cast due to their aggressivity with respect to conventional refractories and the potential occurrence of CaS in the NMI population leading to CaS-induced clogging.…”

Section: Introductionsupporting

confidence: 58%

“…For (ii) approach, i.e. the simplified matrix inversion method, we used a phase model of spinel (MgAl2O4), CaS, MnS, CaO and Al with densities of 4.0, 2.58, 3.99, 3.345, and 3.3 g/cm 3 respectively (Al as a proxy for AlN). From the data in Table 5, which are expressed in inclusion-bound elements as ppm of a bulk-steel composition, it can be seen that the agreement between the methods is generally acceptable.…”

Section: Inclusion Mass Balancementioning

confidence: 99%

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Analysis and Significance of Non-metallic Inclusions in Non Grain-oriented Electrical Steel

et al. 2013

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NMI in electrical steels are known to have a very complex chemical makeup and history of formation, and exert a large influence on the handling of this steel in secondary metallurgy and casting. We have developed routines to analyse the non-metallic inclusion contents of non grain-oriented electrical steels by automated FEG-SEM analysis. We automatically analyze NMI of sizes down to 0.08 μm 2 in a steel that has significant amount of alloyed Si (2.3 wt%) by employing a matrix spectrum subtraction routine that leaves only the signal of the NMI itself to be quantified. We describe data reduction procedures for the NMI populations that consist out of duplexing oxides, sulfides, and nitrides. The chemical complexity can be represented and understood in terms of using a multicomponent projection technique, and based on the analysis of the particles it is possible to calculate quantitatively the amount of elements contained in the NMI assemblage of a steel sample. We find that this mass balance gives results in good to excellent agreement with bulk steel analyses for elements that are dominantly inclusion bound, such as Ca, if the complete inclusion size range above 0.08 μm 2 is taken into account. Based on these data analysis methods, we compare the NMI development in two heats through the secondary metallurgy process. Although the same steel composition was alloyed, the NMI developed vastly different depending on the details of treatment on the ladle furnace.KEY WORDS: electrical steel; non-metallic inclusions; automated inclusion analysis; ladle metallurgy.

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Section: Introductionsupporting

confidence: 58%

Section: Inclusion Mass Balancementioning

confidence: 99%

Analysis and Significance of Non-metallic Inclusions in Non Grain-oriented Electrical Steel

et al. 2013

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“…The existence of this new nitride in silicon steels has only been mentioned previously by Petrovič et al. [19] Li et al. [20] also indicated the solid solution with AlN–Mg 3 N 2 in MgO/AlN composite.…”

Section: Resultsmentioning

confidence: 72%

“…Instead, it was observed a new nitride consisting of aluminium and magnesium. The existence of this new nitride in silicon steels has only been mentioned previously by Petrovič et al[19] Li et al[20] also indicated the solid solution with AlN-Mg 3 N 2 in MgO/AlN composite. Zhukov et al[21] reported the formation of three aluminium magnesium nitrides by mixing and annealing AlN-Mg 3 N 2 powders at 1200°C; AlMg 3 N 3 , Al 2 Mg 3 N 4 and Al 3 Mg 3 N 5 .…”

mentioning

confidence: 66%

Precipitation of nitrides in non-oriented silicon steel

Yong

Zhang

Yang

et al. 2017

Ironmaking & Steelmaking

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In the current work, the effect of rolling process in a plant and cooling rate during the solidification process under laboratory conditions on the formation of precipitation has been investigated. It has been found that a new homogenous nitride is formed by aluminium and magnesium. The formation of nitrides has been described according to a thermodynamic analysis and the values of Al/Mg mass ratio have ranged from 20 to 58 using a model based on data from automatic scanning electron microscopy. Further, MgO refractories have been identified as the main source of Mg for the formation of aluminium magnesium nitrides. In addition, cooling rate has a significant effect on the number density of nitrides. In order to decrease the number density and obtain a larger particle size, reducing cooling rate during solidification can promote a higher grain size and improve the magnetic properties of non-oriented silicon steels.

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“…In addition, MgO inclusion has a different thermal expansion coefficient from the matrix, and forms a void around the inclusions due to the different shrinkage speeds during rapid cooling, forming a source of thermal fatigue cracks. 34) Therefore, the presence of MgO inclusions leads to more defects during processing.…”

Section: Resultsmentioning

confidence: 99%

Inclusion Removal in Molten Magnesium by Pulsed Electric Current

2020

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The effect of pulsed electric current on the removal of MgO inclusions, which deteriorate mechanical and corrosion properties of magnesium alloys, was investigated. Through characterizing the number and size distribution of MgO inclusions, it's found that the MgO inclusions were expelled to the surface (bottom and top) of the magnesium alloy melt and then absorbed by the coating agent, treated by the electropulsing. Besides, the electropulsing also promoted the aggregation of the inclusions, but the large size inclusion only exists on the surface of the sample. Based on the differences in electrical properties between the inclusions and the magnesium alloy melt, a force from electric current to electrically neutral MgO inclusion has been identified to drive the particles' movement. Further, the results of numerical calculation show that under the action of pulse current, the migration of inclusions to the surface can reduce the system free energy, and the aggregation tendency between two inclusions with a relatively large radius is significantly stronger than the two inclusions with a smaller radius. The excellent agreement between numerical calculations and experimental data demonstrates that employing the electropulsing to separate the particles from the liquids is a fantastic new method in metal melt purification.

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Magnesium Non-metallic Inclusions in Non-oriented Electrical Steel Sheets

Cited by 11 publications

References 37 publications

Analysis and Significance of Non-metallic Inclusions in Non Grain-oriented Electrical Steel

Analysis and Significance of Non-metallic Inclusions in Non Grain-oriented Electrical Steel

Precipitation of nitrides in non-oriented silicon steel

Inclusion Removal in Molten Magnesium by Pulsed Electric Current

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