Comparison of Transverse Uniform and Non-Uniform Secondary Cooling Strategies on Heat Transfer and Solidification Structure of Continuous-Casting Billet

Abstract

Water flux distribution largely influences the heat transfer and solidification of continuously-cast steel billets. In this paper, a secondary cooling strategy of transverse non-uniform water flux (i.e., higher flux density on billet center), was established and compared with the uniform cooling strategy using mathematical modeling. Specifically, a heat transfer model and a cellular automaton finite element coupling model were established to simulate the continuous casting of C80D steel billet. The water flux was measured using different nozzle configurations to assist the modeling. The mathematical results were validated by comparing the surface temperature and the solidification structure. It is shown that the non-uniform cooling strategy enables the increase of corner temperature and reduction in surface temperature difference, while a higher reheating rate is found on the surface center of the billet. Moreover, the non-uniform cooling strategy can enhance the cooling effect and refine the solidification structure. Accordingly, the liquid pool length is shortened, and the equiaxed crystal density is increased along with the decreased equiaxed crystal ratio. The uniform cooling strategy contributes to reducing internal cracks of billet, and the non-uniform one is beneficial for surface quality and central segregation. For C80D steel, the non-uniform cooling strategy outperforms the uniform one.

Refining and Casting of Steel

“…The uniform cooling strategy contributes to reducing internal cracks of billet, and the non-uniform one is beneficial for surface quality and central segregation. For C80D steel, the non-uniform cooling strategy outperforms the uniform one [14].…”

“…Three papers are based on the studies, regarding the processes taking place in the mold from the viewpoint of heat transfer and multiphase flow influenced by deep submerged entry nozzle (SEN) immersion [9], nozzle clogging [10], and mold flux interaction with steel [11]. Finally, the authors contributed to this Special Issue by also focusing their attention on the complex phenomenon connected to steel cooling, its solidification and quality [12][13][14][15]. All published contributions and their briefly commented upon abstracts are organized based on the technological flow valid for modern steel production in the next subchapters.…”

“…Han et al [14] reported results from the comparison of different secondary cooling strategies from the viewpoint of heat transfer and the solidification structure of billets. Water flux distribution largely influences the heat transfer and solidification of continuously cast steel billets.…”

Optimization of Thermal Soft Reduction on Continuous-Casting Billet

“…22,23) To consider the effect of the gap on the heat transfer, a decreasing heat flux was used from the billet center to the corner, and the heat flux at the corner decreased with the increase of distance from the meniscus. 24)…”

Defects of the steel billet in continuous casting

“…Steel continuous casting is now very popular to produce semi-finished products (slabs, blooms or billet) in the most suitable cross-section for further shaping [1][2][3][4]. Improving the steel quality and the steelmaking process has been a target of metallurgical engineers and steelmaking companies in a demanding market for better products at highly competitive price [5][6][7][8][9].…”