ISSN 2594-5300
32º Seminário de Aciaria — Vol. 01 , num. 32 (2001)
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Abstract
Control of crystallization within a mold flux is a key factor for optimal operations of steel continuous casting. In previous works it has been shown that mold flux crystallization behavior can be controlled for some extent by doping the flux with suitable transition metal oxide (MnO). Extent of MnO doping has proved to strongly affect crystallization temperature, as measured from DTA analysis (onset of crystallization). Increasing of MnO content in mold flux results in a sharp decrease of Tcry due to important alterations of its crystallizing behavior. In the present work, crystallization of MnO-doped and un-doped mold fluxes has been thoroughly investigated by DTA analysis at different cooling rates to understand the inherent chemical-physical effect induced by MnO. Continuous Cooling Transformation (CCT) diagrams based on DTA data have been taken into consideration to point out the relationship between onset of crystallization and cooling rates. Peculiar effect of MnO addition has been more extensively analyzed on these bases. Calculated values of onset of crystallization obtained by extrapolation at cooling rates approaching zero have been found quite similar to equilibrium break temperatures measured by high temperature rotational viscosimetry.
Control of crystallization within a mold flux is a key factor for optimal operations of steel continuous casting. In previous works it has been shown that mold flux crystallization behavior can be controlled for some extent by doping the flux with suitable transition metal oxide (MnO). Extent of MnO doping has proved to strongly affect crystallization temperature, as measured from DTA analysis (onset of crystallization). Increasing of MnO content in mold flux results in a sharp decrease of Tcry due to important alterations of its crystallizing behavior. In the present work, crystallization of MnO-doped and un-doped mold fluxes has been thoroughly investigated by DTA analysis at different cooling rates to understand the inherent chemical-physical effect induced by MnO. Continuous Cooling Transformation (CCT) diagrams based on DTA data have been taken into consideration to point out the relationship between onset of crystallization and cooling rates. Peculiar effect of MnO addition has been more extensively analyzed on these bases. Calculated values of onset of crystallization obtained by extrapolation at cooling rates approaching zero have been found quite similar to equilibrium break temperatures measured by high temperature rotational viscosimetry.
Keywords
mold fluxes, crystallization behavior, continuous casting, CCT diagrams, DTA analysis
mold fluxes, crystallization behavior, continuous casting, CCT diagrams, DTA analysis
How to cite
Righi, Carlo; Carli, Riccardo; Ghilardi, Valerio.
NEW INSIGHTS UPON CONTROL OF CRYSTALLIZATION BEHAVIOR OF MOLD FLUXES,
p. 245-254.
In: 32º Seminário de Aciaria,
Belo Horizonte, Brasil,
2001.
ISSN: 2594-5300, DOI 10.5151/2594-5300-32Aciaria-245-254
