scholarly journals Combined Effects of EMBr and SEMS on Melt Flow and Solidification in a Thin Slab Continuous Caster

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 948
Author(s):  
Changjun Wang ◽  
Zhongqiu Liu ◽  
Baokuan Li
Keyword(s):  
Continuous Caster ◽  
Solidification Rate ◽  
Potential Method ◽  
Suppressive Effect ◽  
Thin Slab ◽  
Dispersion Effect ◽  
Melt Flow ◽  
Simultaneous Application ◽  
Iron And Steel ◽  
Slab Continuous Caster

Electromagnetic fields have emerged as powerful tools for addressing current problems in thin slab continuous casting processes in the iron and steel industry. Substantial studies have been undertaken on the fundamental effects of electromagnetic brakes (EMBr) and strand electromagnetic stirring (SEMS). However, little attention has been focused on melt flow and solidification in a thin slab continuous caster with the simultaneous application of an EMBr and SEMS. The present study aimed to predict transient fields in the caster using a large eddy simulation and an enthalpy-porosity method. The electric potential method was applied in the braking process, and the conductivity change with solidification was considered. The suppressive effect on the intensity of the nozzle jet, the balance effect on the mold flow, and a dispersion effect could be observed. The dispersion effect was a novel finding and was beneficial to a flatter nozzle jet. In contrast, SEMS caused a highly turbulent flow in the strand. A large vortex could be observed in the casting direction. The solidified shell became more uniform, and the solidification rate became obviously slower. These findings supported the view that a high-quality thin slab can be produced by the application of an EMBr and SEMS.

scholarly journals Physical simulation of liquid steel motion in a thin-slab continuous caster mold

2019 ◽  
Vol 75 (4) ◽  
pp. 454-459
Author(s):  
V. M. Safonov ◽  
V. G. Borisevich ◽  
V. V. Kislitsa ◽  
D. V. Morov
Keyword(s):  
Liquid Steel ◽  
Steel Casting ◽  
Physical Simulation ◽  
Continuous Caster ◽  
Dead Volume ◽  
Mold Surface ◽  
Thin Slab ◽  
Direct Flow ◽  
Deep Layers ◽  
Slab Continuous Caster

Industrial experience of steel casting at the thin-slab continuous caster (CC) revealed processes, having negative effect on the quality of internal structure and surface of CC thin slab. The main problems are as follows: flat streams of liquid steel, flowing through submerged snorkel into restricted dead volume, form circulating flows of extremely high velocity in both liquid core and on the slab surface. This circumstance makes specific requirements to the design and parameters of the submerged snorkel to supply the metal into the thin-slab CC mold. Despite the more than 25 years’ experience of the snorkel form and geometric parameters development, there is no single opinion on its optimal design. Results of physical simulation of the liquid motion processes in a thinslab Caster mold presented (for slab maximum width 1800 mm, thickness – 90 mm) of JSC “Vyksa Steel-works” casting and rolling complex. Description of the physical model facility quoted, as well as description of the experiment methodology and its results. The speed was measured and structure of liquid steel flows revealed in depth and sub-surface layers, as well as in slag-forming mixture at the mold surface. The comparison of two principally different variants of liquid steel feeding into the mold made. The two variants were as follows: by a flat down-directed stream with a narrow central divider (direct-flow submerged snorkel) and by four streams , two of them directed down under an angle relating the vertical axe, and the other (about 20% of total liquid consumption) – directed upward to the bath mirror (the snorkel of “hammer” type). It was determined, that steel casting with technological speed through the direct-flow snorkel was most effective into the slab of 1400 mm width and less, since in this case the sub-surface flows speed did not resulted in the intensive waves formation, constant whirls formation and slag particles dragging into deep layers of the slab. For steel casting into slab of width more than 1400 mm, it is reasonable to use a snorkel of the “hammer” type, which enables to create a favorable stable structure of circulation and decrease the tendency of slag particles dragging in the deep layers of the slab.

Mathematical Modeling of Transport Processes in Funnel Shaped Mold of Steel Thin Slab Continuous Caster

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
A. Hajari ◽  
S. H. Seyedein ◽  
M. R. Aboutalebi
Keyword(s):  
Flow Pattern ◽  
Casting Speed ◽  
Continuous Caster ◽  
Transport Processes ◽  
Inlet Temperature ◽  
High Heat Flux ◽  
Thin Slab ◽  
Surface Turbulence ◽  
Submergence Depth ◽  
Slab Continuous Caster

In this work a three-dimensional fluid flow and heat transfer model was developed to predict the flow pattern and superheat dissipation in funnel shaped mold of a thin slab continuous caster with a novel tetrafurcated design for the submerged entry nozzle. Low Reynolds k−ε turbulent model was adopted to account for the turbulent effect. The transport equations were solved numerically using finite volume method. The results were compared with a full scale water model of the caster. Good agreement between mathematical and physical models was obtained. Parametric studies were carried out to evaluate the effect of casting speed, nozzle submergence depth, and inlet temperature on the superheat dissipation, flow pattern, and surface turbulence in the mold region. The results indicate a special flow pattern and heat distribution in the caster while using a tetrafurcated nozzle. Aiming to achieve more product capacity, in the case of casting with lower superheat temperature, a higher casting speed, together with higher submergence depth, is recommended in order to avoid surface turbulence and high heat flux across the narrow face.

Investigation on New Submersed Entry Nozzle in Slab Caster

2011 ◽  
Vol 287-290 ◽  
pp. 2768-2771
Author(s):  
Yu Ma ◽  
Jing She Li ◽  
Xiao Chuan Lin ◽  
Li Yuan Sun
Keyword(s):  
Penetration Depth ◽  
Continuous Caster ◽  
Surface Velocity ◽  
Slab Caster ◽  
Slab Continuous Casting ◽  
Outlet Angle ◽  
Surface Turbulence ◽  
Continuous Casting Mould ◽  
Better Than ◽  
Slab Continuous Caster

The fluid flow in the mould of slab continuous caster was investigated by 1:1 ratio water modeling simulation system. The effects of outlet angle of Bilateral and quadripuntal SEN on surface turbulence, penetration depth and surface velocity were discussed and the regularity of the flow field for change of outlet angle in slab continuous casting mould was obtained. The results show that the case C (both α and β are downward angle and α<β) is better than the usual SEN, for this kind of SEN can stabilize surface turbulence and reduce penetration depth and get moderate velocity.

Transport Phenomena and the Associated Humping Formation in Laser Welding

2005 ◽  
Author(s):  
J. Zhou ◽  
H. L. Tsai ◽  
P. C. Wang
Keyword(s):  
Heat Transfer ◽  
Liquid Metal ◽  
Laser Welding ◽  
High Speed ◽  
Solidification Rate ◽  
Transport Phenomena ◽  
Metal Flow ◽  
Welding Process ◽  
Solidification Process ◽  
Melt Flow

Humping is a frequently observed welding defect in laser welding which is caused when the welding speed exceeds a certain limit while the other welding conditions remain unchanged. Humping is characterized by the appearance of unsmooth and discontinuity of humps at the surface of the weld. The formation of humping is generally understood to be caused by the complex heat transfer and melt flow in a high speed welding process. However, so far the fundamental mechanisms causing humping are not fully understood, and research on determining the onset of humping has been based on the “trial-and-error” procedure. In this paper, mathematical models previously developed by the authors for the transport phenomena in laser welding have been extended to investigate the formation of the humping defect. In this study, the transient heat transfer and melt flow in the weld pool during the keyhole formation and collapse, and melt solidification are calculated for a 3-D moving laser welding. Different humping patterns have been predicted by the present study in different laser power levels and welding speeds. From the present study, it was found that the formation of humping in laser welding is caused by the interplay between two important factors: a) the strong liquid metal flow in the real part of the keyhole induced mainly by the laser recoil pressure and b) the rapid solidification rate of the liquid metal. The humping pattern can be well explained by the calculated melt flow and the solidification process.

Measurement and Research of Oscillating State of Hydraulic Oscillation in Slab Continuous Casting

2011 ◽  
Vol 130-134 ◽  
pp. 2280-2283
Author(s):  
Yong Ma ◽  
Yu Cheng Wu ◽  
Wen Lin Chen ◽  
Xin Fang Wang ◽  
Ya Pei Zhao
Keyword(s):  
Continuous Casting ◽  
Evaluation Method ◽  
Continuous Caster ◽  
Slab Continuous Casting ◽  
Mold Oscillation ◽  
Sinusoidal Waveform ◽  
Left And Right ◽  
Hydraulic Oscillation ◽  
The Stability ◽  
Slab Continuous Caster

The stability of mold oscillation can directly influence on slab surface quality and operational safety in continuous casting. In recent years, the hydraulic oscillation is developed and applied as the driven equipment of mold oscillation. In the present work, based on the slab continuous caster of hydraulic oscillations, the displacement and other parameters of hydraulic oscillator are measured and the evaluation method of oscillation is studied. The displacement difference and phase difference of oscillation with sinusoidal waveform and non-sinusoidal waveform are analyzed. Especially, the dynamic characteristics of the driving force of left and right cylinders are evaluated. The results indicated that the hydraulic oscillator is quite a good device in terms of precision. The method proposed may be useful for evaluating oscillators.

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