Dynamic Response of Mold Oscillator Interacting with Steel Slabs

Submerged entry nozzle (SEN) clogging is investigated with an emphasis on the interfacial reaction between the nozzle refractory and the liquid steel. Within the context of carbothermically produced CO(g) being the main cause of the early stage SEN clogging, various SEN refractory materials are assessed in view of their impact on the initial clog deposit formation. A series of high‐temperature experiments are carried out to observe the interfacial reaction between the SEN refractory materials and the liquid steel: three oxide‐based and one oxide‐less refractory materials are employed. Ti‐free and Ti‐added ultra‐low C steel are reacted with these refractory materials. The reactivity of the refractories is assessed by 1) the morphology, composition, and thickness of the initial clog deposit and 2) the evolution of steel compositions. Decreasing SiO2 content in “oxide‐based” refractory is recommended. The “oxide‐less” refractory composed of AlON–BN–AlN is shown to be promising to suppress the early stage of SEN clogging. The present results would provide directions for designing the SEN refractory constitution to suppress the SEN clogging.

Section: Countermeasures Of Sen Clogging During Continuous Casting Of...mentioning

confidence: 99%

Assessment of Reactivity between Submerged Entry Nozzle (SEN) and Ultra‐low C Liquid Steel: Comparison between Oxide‐Based SEN and Oxide‐Less SEN

Lee,

Cho,

Kim

et al. 2024

“…Mold oscillation can improve the lubrication of slab, and prevent the molten steel from sticking to copper mold, making the continuous casting process smooth . However, mold oscillation will introduce surface defects like oscillation marks and its related subsurface defects due to the periodically oscillation of the mold, which significantly affects the surface quality of slabs.…”

Section: Formation Of Oscillation Marks Versus Heat Transfermentioning

confidence: 99%

Initial Solidification and Its Related Heat Transfer Phenomena in the Continuous Casting Mold

Wang

Zhu

Zhou

2017

The initial solidification of molten steel in the mold is very important, as it is the origin of the final slab, which associates with the surface defects and determines the final quality of casting slab. In this article, six main topics, including the initial solidification study method, molten steel solidification, mold flux structure, fluid flow, oscillation marks formation, and breakout are reviewed with the purpose to explore the intrinsic mechanism of the complex initial solidification process and its related multi-phase heat transfer phenomena. The results summarized here can provide a foundational understanding of the initial solidification and heat transfer phenomena occurring in the continuous casting mold.

“…Promoting the formation of calcium ferrite in sinter has always been an important issue for decades for reducing coke ratio and ensuring the smooth operation of blast furnaces. [ 5–8 ] While, due to the stronger bonding force for CaO with SiO 2 than that for CaO with Fe 2 O 3 , the formation of calcium silicate was unavoidable in the sintering process. [ 9,10 ] Compared with calcium ferrite, the calcium silicate phases that were formed in sinter possessed relatively higher melting points (above 1450 °C) and worse reducibility.…”

Section: Introductionmentioning

confidence: 99%

Competitive Formation Behavior of Calcium Silicate and Calcium Ferrite in Sintering of Iron Ore Fines

Du,

Wei,

Guo

2024

Calcium silicate is the undesirable bonding phase in sinter with relatively high melting point and poor reducibility, while the formation mechanism in sinter is ambiguous. Herein, the phase transformation, phase quantification, and morphology evolution of calcium silicate and calcium ferrite in CaO‐SiO2‐Fe2O3‐Al2O3 systems under different n(Fe2O3)/n(CaO) and Al2O3 content are investigated. It is found that with the increase of n(Fe2O3)/n(CaO), the calcium ferrite phases transform from Ca2Fe2O5 (C2F) to complex calcium ferrite, and calcium silicate phases including β‐Ca2SiO4 (β‐C2S) and γ‐Ca2SiO4 (γ‐C2S) are promoted. Moreover, small amount (2%) of Al2O3 can effectively promote the content of silico‐ferrite of calcium and aluminum (SFCA) increasing from 20.95% to 46.69%, whereas inhibiting the β‐C2S from 51.79% to 42.34%. When the content of Al2O3 is over 4%, the Ca2Al(AlSiO7) phase is formed, where both the SFCA and calcium silicate are inhibited. On this base, the competitive mechanism for the formation of calcium silicate and calcium ferrite is revealed, where the Ca2+ and Si4+ are preferred to react with Fe3+ and Al3+ to form liquid phase SFCA, while the amount for β‐C2S or γ‐C2S can be decreased due to the deprivation of Ca2+ and Si4+.