an investigation on mold powders properties consumed in iran

this paper describes the work done between iust and two iranian steelworks to evaluate and review the performance of mould fluxes in current use for continuous casting. calculations have been performed to compare actual values of powder consumption, viscosity and break temperature of the fluxes in current use with required values derived from published empirical rules for casting conditions. it has been found that there is, in general, poor agreement between actual and required values. the required viscosities of mould fluxes consumed in mc grades are 2.2 and 1.9 dpas while the measured values are 1.5 and 1.1 dpas, respectively indicating higher values. this situation is reverse in lc grades, and actual viscosities are lower than the measured values based on empirical rules. there is also a disagreement between the carbon content and break temperature of the current fluxes and required values resulting in the defects in produced slabs. these differences are more critical in mc grades. this does not necessarily mean that fluxes are not working well but does imply that a review of mould flux performance is needed before the planned increases in production are implemented. one steel company experienced problems with overflows of steel (bleeds) and with depressions in the surface of the slab. possible reasons for the formation of these defects are proposed.