Abstract
The high content of aluminum in the steel reacts with the CaO-Si2O-based mold fluxes, resulting in deterioration of the mold slag physical and chemical properties, which cannot be applied to the continuous casting molten slag casting process of high-Mn high-Al steel Herein, the thermodynamic and structural properties of low-reactivity CaO-Al2O3-based mold fluxes were investigated. The thermodynamic properties were studied based on the first principles of quantum mechanics. The results show that the formation of stable structures of B-O and O-B-O in the mold fluxes was beneficial to reduce the probability of structural interconnection, degree of polymerization, and viscosity of the molten slag. The increase in the ratio of CaO/Al2O3 = 0.88–2 led to an increase in the O2− concentration. O2− entered the [AlO4] structure to form a stable structure of [AlO6] and [AlO5], wherein [AlO6] was more stable than [AlO5], reducing the degree of polymerization of the network structure. When cosolvent content B2O3 = 2%–10%, a simple layered structure of [BO3] was formed, and the particle migration resistance, break temperature, and viscous activation energy of the mold fluxes were reduced, while the corrected optical basicity of mold fluxes was gradually increased.
Highlights
With the rapid industrialization of China, the demand for high value-added steel has gradually increased, especially for high-Mn-high-Al steel. e high-Mn-high-Al steel has excellent mechanics such as great strength, superb plasticity, and low density. is steel is widely used in several fields such as automotive, marine, and nonmagnetic steel [1,2,3,4,5,6,7].e production of high-Mn-high-Al steel uses ingot casting technology
E main component silica in CaO-SiO2-based mold fluxes reacts with Al and Mn in high-Mn-high-Al steel as shown in equations (1)–(3). e primary chemical reaction is presented in reaction formula (1). e high aluminum content in high-Mn-high-Al steel is the main reason for the deterioration of physical and chemical properties of traditional CaO-SiO2-based mold fluxes [8, 9]
When the CaO-SiO2-based mold flux is in contact with the hightemperature high-Mn-high-Al steel, there is a significant pickup of alumina and dramatic reduction in silica in the spent mold flux. erefore, the low-reactivity CaO-Al2O3based mold fluxes are replacing the traditional CaO-SiO2based continuous casting mold powder [10,11,12,13]
Summary
With the rapid industrialization of China, the demand for high value-added steel has gradually increased, especially for high-Mn-high-Al steel. e high-Mn-high-Al steel has excellent mechanics such as great strength, superb plasticity, and low density. is steel is widely used in several fields such as automotive, marine, and nonmagnetic steel [1,2,3,4,5,6,7].e production of high-Mn-high-Al steel uses ingot casting technology. To improve the production efficiency and reduce costs, several steel industries use continuous casting technology in production. E reaction with traditional CaO-SiO2-based mold fluxes during continuous casting and pouring is as follows: 4[Al] + 3 SiO2 2 Al2O3 + 3[Si], (1). E main component silica in CaO-SiO2-based mold fluxes reacts with Al and Mn in high-Mn-high-Al steel as shown in equations (1)–(3). E high aluminum content in high-Mn-high-Al steel is the main reason for the deterioration of physical and chemical properties of traditional CaO-SiO2-based mold fluxes [8, 9]. The employment of low-reactivity CaO-Al2O3-based continuous casting mold fluxes can meet the technical requirements of the continuous casting process, ensuring a stable and efficient continuous casting production
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