Pohang University of Science and Technology · Engineering
Professor Jung-Wook Cho's research lab specializes in the thermophysical properties and processing behavior of mold fluxes in continuous steel casting, with a focus on heat transfer, rheology, and structural evolution of molten and solidifying slag films. The lab investigates interfacial thermal resistance, radiative and conductive heat transfer mechanisms, and the non-Newtonian rheological behavior of molten fluxes, particularly under high-temperature conditions relevant to advanced high-strength steel (AHSS) casting. Using advanced characterization techniques such as Raman spectroscopy, FTIR, and 27Al MAS NMR, the lab explores the relationship between molecular structure and macroscopic properties like viscosity and crystallization kinetics.
Figures are computed from collected data and may differ slightly.
Today, the demands for Advanced High Strength Steels (AHSS) have gradually increased due to their ability to reduce vehicle weight as a means to save energy, reduce the environmental impact while simultaneously improving passenger safety. However, AHSS often require the addition of large amounts of alloying elements such as aluminum and this can make it difficult to cast sound slabs without surface defects. When casting high aluminum AHSS, due to the reaction between aluminum in steel and silica
Heat transfer from solidifying shell to mold near the meniscus plays an important role for the formation of surface cracks on continuously cast steel products. The heat transfer is influenced substantially by the thermal resistance at the interface between mold flux film and copper mold. Accordingly, a model system consisting of steel shell/mold flux film/copper mold is built to simulate the heat transfer near the meniscus in the mold for continuous casting, and the thermal resistance is determi
Analysis of heat transfer near the meniscus in mold for continuous casting of steel has been carried out by taking into account conductive and radiative thermal resistances of infiltrated mold flux film and thermal resistance at the copper mold/solidifying mold flux film interface. Mold fluxes in commercial use for casting low and medium carbon steel are selected for this study. Thermal conductivities, absorption coefficients and interfacial thermal resistances of these fluxes have been determin
Absorption coefficient and extinction coefficient for various commercial mold fluxes have been determined to quantify the radiative and the total heat transfer through the flux film in continuous casting mold. The absorption coefficient is found to be less than 1000 m-1 for glassy specimens whereas the extinction coefficient is ca. 3000-30000 m-1 for crystalline ones. Comparison of observed with calculated radiative heat flux from the absorption coefficient has shown that gray gas approximation
There have been consistent efforts on understanding rheological behavior of molten mold flux, used in continuous casting of steels. It is prevalent view that molten mold flux shows non‐Newtonian behavior, meaning that the viscosity varies with shear rate history. Hence, the present study attempts to evaluate shear thinning, which is one of the characteristic non‐Newtonian behaviors, by measuring its viscosity with a rotating type viscometer at 1623 K. Furthermore, Raman spectroscopy analysis is
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