Abstract

Abstract Most traditional mold fluxes are Newtonian fluids, and their constant viscosity has certain limitations in continuous casting. A new non-Newtonian fluid mold flux with shear-thinning behavior, i.e., a mold flux with a relatively high viscosity at lower shear rates and a relatively low viscosity at higher shear rates, is required to satisfy the mold-flux performance requirements for high-speed continuous casting. The addition of a certain amount of B2O3 to a CaO–SiO2–Na2O-based mold flux can result in a shear-thinning property. To obtain an improved understanding of the mechanism of this characteristic, a molecular-dynamics simulation method was used to study the microstructural changes of the mold flux. Structural changes of mold-flux samples were analyzed and verified by Raman spectroscopy. The results of the two methods were almost the same, both resulted from the addition of B2O3 and changed the microstructure and degree of polymerization of the mold flux, which resulted in the shear-thinning property of the mold flux. This non-Newtonian fluid mold flux was used in square-billet casting tests, and the quality of the slab was improved effectively.

Highlights

  • Most traditional mold fluxes are Newtonian fluids, and their constant viscosity has certain limitations in continuous casting

  • The results of the two methods were almost the same, both resulted from the addition of B2O3 and changed the microstructure and degree of polymerization of the mold flux, which resulted in the shearthinning property of the mold flux

  • Few studies exist on non-Newtonian fluid mold fluxes, only a few researchers from Japan and South Korea [8, 9] have found that the addition of a certain amount of B2O3 to traditional mold flux can allow it to exhibit a shear-thinning property

Read more

Summary

Introduction

Abstract: Most traditional mold fluxes are Newtonian fluids, and their constant viscosity has certain limitations in continuous casting. The results of the two methods were almost the same, both resulted from the addition of B2O3 and changed the microstructure and degree of polymerization of the mold flux, which resulted in the shearthinning property of the mold flux This non-Newtonian fluid mold flux was used in square-billet casting tests, and the quality of the slab was improved effectively. A mold flux that exhibits a gradual decrease in viscosity with an increase in shear rate, can maintain a relatively high viscosity in the mold-retention area, which reduces the probability of the slag layer being involved in the molten steel, and promotes the flotation of slag inclusions and reduces slab defects. As the shear rate increases, the variation in viscosity is low or remains unchanged, and the traditional mold flux that is used in casting is a typical Newtonian fluid [6]. Based on the problems above, the urgent development of a non-

B-2 B-3 B-4 B-5
Preparation of CaO–SiO2–Na2O-based mold flux
Preparation of CaO–SiO2–Na2O–B2O3-based mold flux
Measurement of viscosity and analysis of shear-thinning behavior
Molecular-dynamics simulation
Quantitative analysis by high-temperature Raman spectroscopy
Applications to continuous casting
Findings
Conclusions
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.