Effect of Slag on Inclusions During Electroslag Remelting Process of Die Steel

Dong, Yun; Jiang, Zhouhua; Cao, Yulong; Yu, Ang; Hou, Dong

doi:10.1007/s11663-014-0070-7

Cited by 81 publications

(56 citation statements)

References 12 publications

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“…13) Extensive research studies have been performed to investigate the effect of operating conditions to the steel cleanliness during ESR process. [14][15][16][17] ESR Operating conditions have been gradually modified to control the steel cleanliness to improve the ingot quality in recent years. 14,15) Dong et al 16) studied the effect of slag composition on the inclusions in ESR ingots based on the experiment of interaction between slag and metal and electroslag remelting.…”

Section: Introductionmentioning

confidence: 99%

Effect of Operating Conditions on Inclusion of Die Steel during Electroslag Remelting

Wang

2018

ISIJ Int.

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The current paper focuses on the effect of different operating conditions on the content of inclusions and cleanliness of remelting ingots. For these investigations, eight ingots were remelted with two slag amount and with two current intensity under otherwise comparable remelting conditions. A twodimensional (2D) coupled mathematical model was employed to simulate the velocity field, solidification and inclusion motion for a system of electrode, slag and ingot in electroslag remelting (ESR) processes, to reveal the inclusion removal mechanism. The results showed that the content of large-sized inclusions in ESR ingot was decreased by approximately 66.18% when the slag amount was increased from 17.85 kg to 20.50 kg. Because of the increase of slag amount, the metal and slag flow faster and the maximal velocity increases by 10.3%, thus there is an increasing trend in trajectories of inclusions (i.e., inclusion motion) in slag pool resulted from the stronger natural convective flow, which is beneficial for the inclusion removal. When the average current was increased from 4 kA to 5 kA, the content of large-sized inclusions in ESR ingot was decreased by approximately 51.38%. Because of the increasing of current, the flow in the middle of the slag pool becomes stronger and the maximal downward velocity increases by 2.7%, thus there is an increasing trend in the renewal rate of the metal film surface due to the stronger washing by slag flow, which can promote the inclusion removal.

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Section: Introductionmentioning

confidence: 99%

Effect of Operating Conditions on Inclusion of Die Steel during Electroslag Remelting

Wang

2018

ISIJ Int.

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“…33 Normally, inclusions easily initiate micro-voids and cracks at the inclusion/steel interface, which can be the origin of fatigue fracture or other defects. Also, ESR steel is not an exception.…”

Section: Solidification and Structurementioning

confidence: 99%

“…41,42 The removal efficiency of inclusions increases with the reduced melting speed. 43 The research work of Y.-W. Dong et al 44 was focused on the impact of fluoride-containing slag and interactions at the slag-metal interface on the non-metallic inclusions in steel. Results indicate that a multi-component slag (CaF 2 , CaO, Al 2 O 3 , SiO 2 , MgO) has a better capacity for controlling the amount of inclusions.…”

Section: Solidification and Structurementioning

confidence: 99%

Electroslag remelting: A process overview

Arh¹,

Podgornik²,

Burja³

2016

Mater. Tehnol.

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The electroslag remelting process (ESR) is important because it provides better control of the solidification microstructure and chemical homogeneity; it also enables greater cleanliness and better mechanical properties. The manufactured high-alloyed steels and other alloys with a controlled chemical composition are used in aerospace, in thermal-and nuclear-power plants, in chemical engineering, for military equipment, special tools, etc. An overview and the basics of the ESR process are presented in this paper.

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“…[5] and [6], magnesium fluoride is generated when fluorine ions destroy the magnesia structure. However, it is volatile under the condition of high temperature and vacuum.…”

Section: Analysis Of Loss Of Fluorinementioning

confidence: 99%

“…[1][2][3][4][5][6][7][8] During the industrial production of magnesium using the Pidgeon process in China, calcium fluoride may be added at a nominal rate of 0.2 kg per 1 kg of pure magnesium. [9] Calcium fluoride also obviously enhances the reaction rate of magnesia in the preparation of magnesium using vacuum carbothermic reduction method.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Calcium Fluoride Acceleration for Vacuum Carbothermic Reduction of Magnesia

Jiang

Liu

et al. 2015

Metall Mater Trans B

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The use of a small amount of calcium fluoride as an additive greatly accelerated the reduction of magnesia during the preparation of magnesium from magnesia using the vacuum carbothermic reduction method. At 1573 K (1300°C), the magnesia reaction rates of the samples with 1, 3, and 5 pct CaF 2 were all approximately 26 pct, three times that of free CaF 2 , and they were arranged in order of the calcium fluoride weight percentages at 1673 K (1400°C). The residues were analyzed using chemical analysis, XRD, SEM, EDS, and XRF. The possible acceleration mechanism was discussed. Calcium fluoride combined with magnesia and silicon dioxide to form a eutectic that melted as a channel to aid the solid-solid reaction between carbon and magnesia at approximately 1573 K (1300°C). Calcium fluoride in the molten state offered free calcium ions and fluorine ions. Fluorine ions entered and distorted the magnesia crystal lattice. The structural strength and chemical stability of the magnesia crystal lattice decreased, which facilitated the magnesia reduction by carbon. Calcium ions were employed to generate the calcium and magnesium silicate. The easyly evaporating fluorides, including magnesium fluoride and silicon tetrafluoride, were regarded as the main reason for the loss of fluorine.

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Effect of Slag on Inclusions During Electroslag Remelting Process of Die Steel

Cited by 81 publications

References 12 publications

Effect of Operating Conditions on Inclusion of Die Steel during Electroslag Remelting

Effect of Operating Conditions on Inclusion of Die Steel during Electroslag Remelting

Electroslag remelting: A process overview

Mechanism of Calcium Fluoride Acceleration for Vacuum Carbothermic Reduction of Magnesia

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