Structure and viscosity of CaO–Al₂O₃–B₂O₃–BaO slags with varying mass ratio of BaO to CaO

Abstract

Advanced high-strength steel (AHSS), including transformation-induced plasticity steel and twinning-induced plasticity steel have received intense interest in recent years because of their excellent combination of high strength, good ductility, and lower density. 1,2 In transportation applications, AHSS can be used to design structures with smaller material thicknesses, which saves weight and thereby decreases the fuel consumption and CO 2 emissions of vehicles. 3 However, one of the challenging concerns for production of AHSS in industrial scale is the strong reaction between steel and mold fluxes during continuous casting, 4 which typically leads to problems of lubrication and heat transfer between mold and solidifying steel. 5 Mold fluxes play an indispensable role in continuous casting of steels and provide two critical functions as lubricating the steel shell and controlling the horizontal heat transfer. The fulfillment of functions for mold fluxes relies on the properties of mold fluxes, for example, viscosity at high temperature (more than 1000°C) and crystallization from molten and glassy fluxes. Therefore, one of the most important tasks for the production of AHSS is to develop mold fluxes that could meet the demand of smooth casting of steel. One solution for this is to develop nonreactive

Unveiling Non-isothermal Crystallization of CaO–Al2O3–B2O3–Na2O–Li2O–SiO2 Glass via In Situ X-ray Scattering and Raman Spectroscopy

“…The PDF, G ( r ), depicts the distributions of all atom–atom distances in the sample and can provide information on the in situ changes in the local structures of an amorphous/crystalline material. 23 As seen in Figure 5 a, short-range order up to <5 Å and long-range disorder >10 Å are clear for the flux up to 400 °C. Weak structural correlations are seen in the medium range (5–10 Å).…”

“…Meanwhile, most of the research on the crystallization of glasses mainly focuses on stoichiometry glasses with only a few components, 21 whereas mold flux glasses contain more than five components to tune the properties and behaviors (viscosity, melting, and crystallization). 8 , 22 , 23 For example, alkali, mainly Li and Na oxides added into the glasses, provides free oxygen in the glass network and decreases the viscosity. The tendency of crystallization of such glassy fluxes is high, and the crystalline products usually have variations in compositions compared with the glass matrix.…”

Effect of SiO₂ Content and Mass Ratio of CaO to Al₂O₃ on the Viscosity and Structure of CaO–Al₂O₃–B₂O₃–SiO₂ Slags

“…The Raman shifts and area fractions of various peaks are listed in Table 3. Firstly, the low frequency region can be fitted by two characteristic peaks between 500 cm -1 and 650 cm -1 , which corresponds to bending vibrations of Al-O-Al and B-O-Al bridge 22,30,31,[32][33][34][35][36] . Al-O-Al refers to the bridge oxygen bond shared between [AlO 4 ], while B-O-Al is the bending vibration between [AlO 4 ] and [BO 3 ].…”

“…The bands at around 850cm -1 and 900cm -1 can be assigned to be the vibration of silicate structural units Q 0 (Si) and Q 1 (Si) respectively [34][35][36][37][38][39] . The band at around 930cm -1 is attributed to the vibration of orthoborate (BO 3 3-) 22,30,31,37) .…”

Comprehensive Understanding of the Role of Carbon Black in the Sintering and Melting Behavior of Mold Flux

“…Considering the viscosity of melt is related to its structure, Raman spectroscopy was adopted to understand the quantitative structural information of molten slag to verify the influence of SiC on the viscosity of molten slag. [37][38][39][40] The silicate network tetrahedral vibration band of between 800 cm − 1 to 1 200 cm − 1 deconvoluted by Gaussian method was used to analyze the [SiO 4 ] 4 − tetrahedral structural unit. [41][42][43] Figure 12 shows the deconvoluted Raman peaks of samples A and B.…”