Effect of alumina pickup on mould flux viscosity in continuous slab casting

Abstract

In the present work, the amount of alumina pickup in sequence casting was evaluated, and the effect on mould Mould flux samples were taken from a continuous flux viscosity quantified. Changes in crystallisation were slab caster mould at various stages during casting also assessed, and will be presented in a future paper. sequences. These confirmed that the amount of alumina pickup reaches a steady state level within the first 40 min of casting (in agreement with a EXPERIMENTAL PROCEDURE simple model of alumina pickup). The steady stateMeasurement of alumina increase level was 3-4 mass-% higher than the originalThe first aim was to clarify two issues regarding alumina alumina content of the flux. Viscosity measurements increase in the mould flux during practical continuous carried out on two commercial mould fluxes, with casting: (i) the actual extent of alumina increase in modern different levels of alumina added, showed that the clean steel manufacture and (ii) the time taken to reach a viscosity increase as a result of a 4 mass-% increase steady state mould flux composition. in alumina is not likely to affect mould behaviour.Mould flux samples were obtained from two carbon steel Comparison of the measured viscosities with slab casters at the Vanderbijlpark, South Africa plant of predictions from literature models showed that no Iscor Ltd. The casters process mainly low carbon, aluminium single literature model corresponds consistently to killed steels (none of it calcium treated during the present the measured values.I&S/1504 investigation). Samples were collected from the same position in the mould (approximately halfway between the sub-The authors are in the Department of Materials Science and merged entry nozzle and the narrow face of the mould) at

Viscosity effect of titanium pickup by mould fluxes for stainless steel

“…In both cases, steady state compositions are achieved within 20 min of the start of the cast, similar to alumina pickup by carbon steel mould fluxes (it was shown that the time constant of the change in composition is approximately equal to the time required for one exchange of the pool of molten mould flux through flux consumption and replacement by fresh powder). 13 Investigation of polished mould flux samples by SEM showed no sign of titanium nitride (Fig. 3), nor was this phase detected by X-ray diffraction.…”

Effect of Slag Compositions and Additive on Heat Transfer and Crystallization of Mold Fluxes for High-Al Non-magnetic Steel

“…Considerable efforts and optimization [5][6][7][8][9][10] have been carried out to study and suppress these changes in compositions and properties of mold fluxes for high-Al steel based on conventional CaO-SiO 2 system mold fluxes. However, no effective solutions to these problems are proposed based on the conventional CaO-SiO 2 system.…”

Development of Mold Flux for Heat-Resistant Alloy Containing Al and Ti

“…[10,11] This behavior may be due to the following factors: (i) The consumption of mold powder when casting Incoloy 800 is about 0.9 kg t À1 , which is considerably higher than the consumption of mold flux, about 0.3-0.5 kg t À1 [12,13] when casting traditional grades. Figure 7 shows the changes in melting behavior and viscosity of mold flux during continuous casting of Incoloy 800.…”