Application of Mean Age Theory in Multi-strand Tundish

Sheng, Dong-Yuan

doi:10.2355/isijinternational.isijint-2022-286

Cited by 5 publications

(3 citation statements)

References 28 publications

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“…In contrast, adding flow control devices offers a direct and efficient method that involves minimal changes to refractory materials, resulting in lower costs and improved metallurgical outcomes in the tundish. 12,13…”

Section: Introductionmentioning

confidence: 99%

Structural optimisation of three-strand asymmetric tundish for super large round bloom continuous casting

Chen,

Bai,

Feng

et al. 2024

Ironmaking & Steelmaking: Processes, Products and Applicati

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In recent years, there has been significant development in the large-scale utilisation of round bloom continuous casting, which has led to an increase in the strand spacing of the tundish. However, this increase often accompanies issues such as poor consistency among each strand. This study focuses on the three-strand asymmetric tundish used in super-large round bloom continuous casting and uses a combination of numerical simulation and physical experiment to investigate the impact of different dam and retaining wall structures on the flow, temperature and removal of inclusions in the super-large round bloom tundish. The reliability of the model is verified through isothermal Water model experiments. The results indicate that by employing an optimised flow control structure with a U-shaped retaining wall featuring small diversion holes and a dam near each of strands No.1 and No.3, several improvements are achieved compared to the prototype tundish. The dead zone ratio of the tundish is reduced by 16.33%, the standard deviation of average residence time decreases by 167.07 s, the volume of the tundish's low temperature zone decreases by 7.79% and the total inclusion removal ratio increases by 14.44%. By appropriately incorporating dams, reducing the area of diversion holes and modifying the retaining wall structure in the tundish, the flow, temperature and inclusion removal consistency of each strand can be effectively improved. This enhances the overall metallurgical efficiency of the tundish. Even when encountering strand blocking operation, the dead zone ratio can be further reduced to 22.44% using the optimised structure proposed in this study. This demonstrates that the optimised structure not only improves the steady-state metallurgical behaviour of the asymmetric three-strand tundish with large strand spacing for super-large round bloom but is also suitable for addressing unsteady-state metallurgical behaviour caused by on-site working conditions, such as production scheduling or high casting speed. By implementing the findings of this study, it is expected that the efficiency and effectiveness of the super-large round bloom continuous casting process will be significantly enhanced.

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Section: Introductionmentioning

confidence: 99%

Structural optimisation of three-strand asymmetric tundish for super large round bloom continuous casting

Chen,

Bai,

Feng

et al. 2024

Ironmaking & Steelmaking: Processes, Products and Applicati

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“…In order to exert the metallurgical function of the tundish, many approaches have been proposed, such as the application of channel-type induction heating [4][5][6] , the control of the multiphase flow in tundish during ladle exchange 7,8) , the development of an innovative ladle shroud 9,10) and optimization of the flow control devices in tundishes [11][12][13][14][15] . The study of tundish is usually carried out by using physical modeling and/or numerical simulation [16][17][18][19] methods to obtain the expected structure of tundish, then it is applied to industrial practice. This is frequently proved to be effective.…”

Section: Introductionmentioning

confidence: 99%

Flow Control to a T-shaped Five-strand Tundish for Its Overall Enhanced Metallurgical Effects with an Approachable Identical Products Quality

et al. 2023

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In response to the frequent problem of inconsistent quality of billet castings and their rolled products from each strand by a five-strand tundish, the flow field in tundish is optimized by presenting new flow control devices and conducting isothermal physical modelling along with numerical simulation. The results show that the dead volume fraction of the optimized case A6 is reduced from 27.74% to 19%, the stagnation time is prolonged from 12 s to 35 s, and the flow dynamic consistency for each strand is improved as well. In the subsequent industry production tests, the temperature difference of molten steel at the outlet of each strand is reduced to 1~5 ℃.The maximum difference of the as-cast equiaxed crystal rate among five strands is reduced from 5.67% to 2.7%, and the consistency of carbon segregation index is also improved with a basically identical appearance through the billet cross section. The maximum differences in oxygen and nitrogen contents for the rolled products of all strands are 2.7 ppm and 5.7 ppm respectively, which are lower than 5.0 ppm and 13.8 ppm before tundish optimization. The yield strength of rolled products is stabilized with much less divergence as compared to the products with the original tundish. Thus, it is believed that the reasonable flow field optimization to a multi-strand tundish not only will have a well-known positive impact on its tranditional metallurgical effect, but also may bring out an approaching identical steel quality from the same caster as we expected.

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“…The feasibility of applying the mean age theory in the design of multi-strand tundish was confirmed. 22) It is therefore natural to investigate the possibility to use the mean age theory for the design of single-strand tundish since the flow characteristics are different between the single-strand and multi-strand tundish. The criterion of the flow consistency in multi-strand tundish is not valid for the design of singlestrand tundish where the mixing performance is one of the most important factors.…”

Section: Introductionmentioning

confidence: 99%

An Integrated Workflow for Designing a Single-strand Tundish Using CFD-Taguchi Method and Mean Age Theory

Sheng

2023

ISIJ Int.

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The flow control devices (FCD) play an important role to realize the best metallurgical performance of the tundish. An integrated workflow for designing a single-strand tundish equipped with FCD is presented in this paper. Mean age theory was applied to predict the spatial mean age distributions in the tundish. Melt change efficiency (MCE) was used as a key measure to characterize the tundish's mixing performance. Taguchi method was employed to optimize the design factors, i.e. geometrical parameters of the FCD. The fluid flow and mixing of materials were analyzed based on the numerical simulations of a developed computational fluid dynamics (CFD) model. Compared to the residence time distribution (RTD) method, the mean age theory shows advantages in both numerical accuracy and efficiency. In addition, the size and location of undesired mixing zones can be easily identified which is essential for tundish design. The developed workflow that combined the CFD-Taguchi method and mean age theory can be used as an efficient tool for wide industrial applications.

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Application of Mean Age Theory in Multi-strand Tundish

Cited by 5 publications

References 28 publications

Structural optimisation of three-strand asymmetric tundish for super large round bloom continuous casting

Structural optimisation of three-strand asymmetric tundish for super large round bloom continuous casting

Flow Control to a T-shaped Five-strand Tundish for Its Overall Enhanced Metallurgical Effects with an Approachable Identical Products Quality

An Integrated Workflow for Designing a Single-strand Tundish Using CFD-Taguchi Method and Mean Age Theory

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