scholarly journals Optimization on Reducing Slag Entrapment in 150 × 1270 mm Slab Continuous Casting Mold

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1774 ◽  
Author(s):  
Yang Wang ◽  
Shufeng Yang ◽  
Feng Wang ◽  
Jingshe Li
Keyword(s):  
Numerical Simulation ◽  
Continuous Casting ◽  
Casting Speed ◽  
Surface Velocity ◽  
Continuous Casting Mold ◽  
Slab Continuous Casting ◽  
Eddy Simulation ◽  
Submerged Entrance Nozzle ◽  
Dynamics Simulations ◽  
Slag Entrapment

To reduce slag entrapment in 150 × 1270 mm slab continuous casting molds at the Tang Steel Company, the effect of submerged entrance nozzle (SEN) depth and casting speed on the phenomenon was studied by computational fluid dynamics simulations. Then, the slag entrapment behavior in continuous casting molds, utilizing Large Eddy Simulation (LES) by coupling the volume of fluid (VOF) method, was also used. Finally, the effect of several common oils usually used to simulate slag in water modelling on slag entrapment was discussed and the water modelling results were used to validate the numerical simulation findings. The results showed that the optimum scheme is a submerged depth of SEN 90 mm and a casting speed of 1.6 m/min. Under optimal conditions, the maximum surface velocity is smallest (0.335 m/s) and the maximum slag entrapment ratio (0.44%) appears in the position of 0.1 m below the meniscus after 15 s. The water modelling results were in good agreement with the numerical simulation results.

scholarly journals Influence of M-EMS on Fluid Flow and Initial Solidification in Slab Continuous Casting

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3681
Author(s):  
Guoliang Liu ◽  
Haibiao Lu ◽  
Bin Li ◽  
Chenxi Ji ◽  
Jiangshan Zhang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Field ◽  
Continuous Casting ◽  
Casting Speed ◽  
Liquid Pool ◽  
Industrial Test ◽  
Magnetic Flux Density ◽  
Continuous Casting Mold ◽  
Slab Continuous Casting ◽  
Initial Solidification

A mathematical model coupled with electromagnetic field has been developed to simulate the transient turbulence flow and initial solidification in a slab continuous casting mold under different electromagnetic stirring (EMS) currents and casting speeds. Through comparing the magnetic flux density, flow field with measured results, the reliability of the mathematical model is proved. The uniform index of solidified shell thickness has been introduced to judge the uniformity of the solidified shell. The results show that a horizonal recirculation flow has been generated when EMS is applied, and either accelerated or decelerated regions of flow field are formed in the liquid pool. Large EMS current and low casting speed may cause the plug flow near the mold narrow face and a suitable EMS current can benefit to the uniform growth of solidified shell. Meanwhile, an industrial test exhibits that EMS can weaken the level fluctuation and number density of inclusion. Overall, a rational EMS current range is gained, when the casting speed is 1.2 m/min, the rational EMS current is 500–600 A.

scholarly journals Influence of EMS on Asymmetric Flow with Different SEN Clogging Rates in a Slab Continuous Casting Mold

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1288
Author(s):  
Bin Li ◽  
Haibiao Lu ◽  
Yunbo Zhong ◽  
Zhongming Ren ◽  
Zuosheng Lei
Keyword(s):  
Flow Field ◽  
Continuous Casting ◽  
Submerged Entry Nozzle ◽  
Casting Process ◽  
Continuous Casting Mold ◽  
Continuous Casting Process ◽  
Slab Continuous Casting ◽  
Safe Level ◽  
Mold Flow ◽  
Slag Entrapment

Submerged entry nozzle (SEN) clogging is a troublesome phenomenon in the continuous casting process that can induce the asymmetric mold flow, and thus, lowering the steel product quality. In this paper, a mathematical model coupling the electromagnetic and flow fields, was developed to investigate the influence of the SEN clogging rate on the flow field and the influence of electromagnetic stirring (EMS) on the asymmetric mold flow. Slag entrapment index Rc was introduced to quantify the possibility of slag entrapment, and symmetric index S was introduced to quantify the symmetry of the flow field. The results show that as the SEN clogging rate increased, the slag entrapment index Rc increased, while the symmetric index S decreased. EMS can greatly improve the symmetry of the flow field with SEN clogging, but it cannot remove the asymmetric phenomenon completely because the stirring intensity should be controlled below the safe level to avoid slag entrapment.

scholarly journals Measurement of Molten Steel Velocity near the Surface and Modeling for Transient Fluid Flow in the Continuous Casting Mold

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 36 ◽  
Author(s):  
Tao Zhang ◽  
Jian Yang ◽  
Peng Jiang
Keyword(s):  
Continuous Casting ◽  
Molten Steel ◽  
Casting Speed ◽  
Surface Defects ◽  
Transient Flow ◽  
Flow Behavior ◽  
Surface Velocity ◽  
Phase Method ◽  
Mold Surface ◽  
Continuous Casting Mold

In the current work, a rod deflection method (RDM) is conducted to measure the velocity of molten steel near the surface in continuous casting (CC) mold. With the experimental measurement, the flow velocity and direction of molten steel can be obtained. In addition, a mathematical model combining the computational fluid dynamics (CFD) and discrete phase method (DPM) has been developed to calculate the transient flow field in a CC mold. The simulation results are compared and validated with the plant measurement results. Reasonable agreements between the measured and simulated results are obtained, both in the trends and magnitudes for the flow velocities of molten steel near the mold surface. Based on the measured and calculated results, the velocity of molten steel near the surface in the mold increases with increasing casting speed and the casting speed can change the flow pattern in the mold. Furthermore, three different types of flow patterns of molten steel in the mold can be obtained. The pattern A is the single-roll-flow (SRF) and the pattern C is the double-roll-flow (DRF). The pattern B is a transition state between DRF and SRF, which is neither cause the vortices nor excessive surface velocity on the meniscus, so the slag entrainment rarely occurs. Argon gas injection can slow down the molten steel velocity and uplift the jet zone, due to the buoyancy of bubbles. Combination of the measurement and numerical simulation is an effective tool to investigate the transient flow behavior in the CC mold and optimize the actual operation parameters of continuous casting to avoid the surface defects of the automobile outer panels.

scholarly journals Large Eddy Simulation of Multi-Phase Flow and Slag Entrapment in a Continuous Casting Mold

Metals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 7 ◽  
Author(s):  
Xianglong Li ◽  
Baokuan Li ◽  
Zhongqiu Liu ◽  
Ran Niu ◽  
Yanqiang Liu ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Continuous Casting ◽  
Vortex Formation ◽  
Three Dimensional ◽  
Particle Model ◽  
Continuous Casting Mold ◽  
Casting Mold ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Slag Entrapment

A transient, three-dimensional mathematical model has been developed to study the slag entrapment in a continuous casting mold. The unsteady turbulent flow is computed using the large eddy simulation (LES). The sub-grid scale structure is modeled by the Smagorinsky–Lilly model. The movements of discrete bubbles, as well as three continuous phases (air–slag–steel), are described by solving the coupled discrete particle model and volume of fraction (DPM+VOF) approach. The bubble transport inside different phases (steel and slag) and the escape near the air–slag interface are well studied. Good agreement is obtained by comparing with the plant observation of the slag eyes on the top surface of the mold. Three main mechanisms of slag entrapment are identified; vortex formation, shear-layer instability, and meniscus fluctuation. Four stages are observed for a slag entrapment: deformation, necking, breaking, and dragging in the mold. The model is helpful for understanding the formation of slag entrapment during continuous casting.

scholarly journals Comparison of the Flow Field in a Slab Continuous Casting Mold between the Thicknesses of 180 mm and 250 mm by High Temperature Quantitative Measurement and Numerical Simulation

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1886
Author(s):  
Yibo Liu ◽  
Jian Yang ◽  
Fuxiang Huang ◽  
Keran Zhu ◽  
Fenggang Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
High Temperature ◽  
Flow Field ◽  
Continuous Casting ◽  
Quantitative Measurement ◽  
Powder Layer ◽  
Mold Surface ◽  
Continuous Casting Mold ◽  
Casting Mold ◽  
Slab Continuous Casting

In the present work, the flow field in a slab continuous casting mold with thicknesses of 180 and 250 mm are compared using high temperature quantitative measurement and numerical simulation. The results of the numerical simulation are in agreement with those of the high temperature quantitative measurement, which verifies the accuracy and reliability of the numerical simulation. Under the same working conditions, the velocities near the mold surface with the thickness of 180 mm were slightly higher than those of the mold with the thickness of 250 mm. The flow pattern in the 180 mm thick mold maintains DRF more easily than that in 250 mm thick mold. The kinetic energy of the jet dissipates faster in the 250 mm thick mold than in the 180 mm mold. For double-roll flow (DRF), as the argon gas bubbles can be flushed into the deeper region under the influence of strong jets on both sides, the argon bubbles distribute widely in the mold. For single-roll flow (SRF), as the argon bubbles float up quickly after leaving the side holes, the bubble distribution is more concentrated in the width direction, which may cause violent interface fluctuation and slag entrainment. The fluctuation at the steel-slag interface in the mold with 180 mm thickness is greater than that in the mold with 250 mm thickness but less than 5 mm. The increase of mold thickness may lead to a decrease of the symmetry of the flow field in the thickness direction and uniformity of mold powder layer thickness. In summary, the steel throughput should be increased in the 250 mm thick mold compared with that in the 180 mm thick mold.

scholarly journals Measurement of Surface Velocity in a 150 mm × 1270 mm Slab Continuous-Casting Mold

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 428
Author(s):  
Yang Wang ◽  
Jie Feng ◽  
Shufeng Yang ◽  
Jingshe Li
Keyword(s):  
Continuous Casting ◽  
Particle Image ◽  
Slag Layer ◽  
Surface Velocity ◽  
Continuous Casting Mold ◽  
Casting Mold ◽  
Slab Continuous Casting ◽  
Image Velocimetry ◽  
Nail Diameter

Surface velocity in the continuous-casting mold needs to be studied to better control the quality of steel products. In this paper, the measurement of surface velocity in a 150 mm × 1270 mm slab continuous-casting mold was investigated. Taking the slag layer into consideration, a numerical simulation was performed which was validated by a particle image velocimetry test. A nail-board experiment was also conducted to measure surface velocity in the continuous-casting mold. The effect of nail diameter used in nail-board experiment on the measurement of the surface velocity was also discussed to improve the precision of nail-board experiment result. The results showed that the maximum surface velocity was 0.739 m/s around the mid-section of the free surface, and the results of nail-board experiments were more accurate when the steel nail diameter was 10 mm.

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