Influence of Joint EMSFN and M-EMS on Fluid Flow in the Mold During Continuous Casting

doi:10.1007/s40195-018-0800-y

Abstract

Abstract:

Homogenization of physical properties and the chemical composition through the control of liquid metal flow is essential during the continuous casting production of billets. This work was aimed at obtaining improved finished products via continuous casting that implements two magnetic fields. These fields were realized via two electromagnetic stirring processes implemented in a single process: one in the nozzle and one in the mold. The qualitative effects of applying double electromagnetic stirring (EMS) were verified through numerical simulation of 178 mm?×?178 mm square billets exposed to double electromagnetic fields during the continuous casting process. The accuracy of the numerical calculations was verified via physical experiments. In addition, the final simulation results were compared with the intermediate results, to determine the true effects of different EMS on the metal flow in the mold. The results revealed that casting using EMS with different directions of magnetic field in the mold and the nozzle has the best effect on the distribution of the fluid flow and minimal influence on the stability of the meniscus and yields the minimum metal-jet penetration into the mold.

Key words: Continuous casting, Submerged nozzle, Electromagnetic stirring, Microstructure

Oleksandr Tretiak, Qiang Wang, De-Wei Li, Xiao-Wei Zhu, Chun-Lei Wu, Ming He. Influence of Joint EMSFN and M-EMS on Fluid Flow in the Mold During Continuous Casting[J]. Acta Metallurgica Sinica (English Letters), 2018, 31(12): 1345-1356.

Figures/Tables 18

Fig. 1 Calculation model (unit: mm)

Fig. 2 Simulation of the magnetic field: 1—submerged nozzle, 2—electromagnetic coils, 3—core of the electromagnetic device and its contour

Table 1 Chemical composition of the studied steel (wt%)

C	Si	Mn	P	S	Cr	Ni
0.698	0.201	0.560	0.013	0.013	0.036	0.012

Table 2 Industrial experimental conditions

Sample	Direction of EMS in a submerged nozzle	M-EMS	EMSFN current (A)
(a)	-	Counterclockwise	-
(b)	Counterclockwise	-	200
(c)	Counterclockwise	-	400
(d)	Counterclockwise	Counterclockwise	400
(e)	Counterclockwise	Counterclockwise	600
(f)	Clockwise	Counterclockwise	200
(g)	Clockwise	Counterclockwise	400

Fig. 3 Distribution of velocities in the mold: a without EMS, b EMSFN, c M-EMS

Fig. 4 Distribution of velocities in the meniscus: a without EMS, b EMSFN, c M-EMS

Fig. 5 Distribution of velocities with EMSFN: a 200 A, b 300 A, c 400 A

Fig. 6 Distribution of the maximum tangential velocities in the upper part of the mold a without stirring, and with stirring in the b nozzle, c mold

Fig. 7 Metal-jet penetration into the mold with: C—clockwise, ConC—counterclockwise

Fig. 8 Distribution of the main flows in a the absence, b under the influence of Coriolis forces

Fig. 9 Distribution of velocities in meniscus obtained via double EMS: a clockwise EMSFN and clockwise M-EMS, b counterclockwise EMSFN and clockwise M-EMS, c counterclockwise EMSFN and counterclockwise M-EMS, d clockwise EMSFN and counterclockwise M-EMS

Fig. 10 Distribution of velocities in mold obtained via double EMS: a clockwise EMSFN and clockwise M-EMS, b counterclockwise EMSFN and clockwise M-EMS, c counterclockwise EMSFN and counterclockwise M-EMS, d clockwise EMSFN and counterclockwise M-EMS

Fig. 11 Dependence of jet penetration on the casting direction: a clockwise M-EMS, b counterclockwise M-EMS, c clockwise EMSFN and clockwise M-EMS, d counterclockwise EMSFN and clockwise M-EMS, e counterclockwise EMSFN and counterclockwise M-EMS, f clockwise EMSFN and counterclockwise M-EMS

Fig. 12 Deviation of pearlite dispersion in cross-sectional area from the average dispersion (for conditions shown in Table 2)

Fig. 13 Placement position and nomination of samples

Fig. 14 Elemental distribution of samples shown in Fig. 13 and Table 2

Table 3 Results of hardness measurements

Number	Value of hardness (HRA)					Average
Number	1	2	3	4	5	Average
(a)	65	63	58	63	64	62.6
(b)	58	61	66	65	60.5	62.1
(d)	65	63	61	62	63	62.8
(e)	67.5	63	63	63	60	63.3
(g)	62	65	61	66	66.5	64.1

Fig. 15 Images of different samples taken from the central zone (point 5 in Fig. 13, condition Table 2)

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