Viscosity, Density, Surface Tension, and Crystallization Behavior of Commercial Mold Fluxes

Abstract

This study investigates the viscosity, density, surface tension, and crystallization behavior of two commercial mold fluxes that are utilized to cast ultralow-carbon, low-carbon, and medium-carbon steel grades, as well as electric steels (high-B magnetic and grain-oriented steels). Experiments are performed in the temperature range of 1073–1673 K using the rotating bob method, maximum bubble pressure method, buoyancy method, and single hot thermocouple technique. The phase structure is investigated via scanning electron microscopy and X-ray powder diffraction. The results indicate that viscosity and density exhibit nonlinear temperature dependence. Increased basicity (CaO/SiO2) results in reduced viscosity and elevates the break temperature of the mold fluxes. Furthermore, the incubation time required for phase formation decreases with increasing basicity. Finally, time–temperature transformation and continuous cooling transformation diagrams are constructed.