Active Tundish Slag

Abstract

The concept of ''active tundish slag'' aims definitely at improving of steel cleanliness by tailoring a proper tundish slag. In this project, active tundish metallurgy was investigated and assessed. Computation of phase diagrams was used as an approach to understand properties and behavior of tundish slags in casting conditions. Eventual reactions between steel and slag in the tundish were examined by equilibrium calculations. Interfacial phenomena controlling inclusion removal and dissolution into tundish slag were investigated by applying several experimental techniques. Dissolution of alumina and spinel inclusions into slag were studied by model experiments applying CLSM and DHTT methods. Viscosity of slags was measured at different temperatures. Interfacial tension between steel and slag was measured by drop weight method for several slag/steel systems. The study showed the complexity and multi-disciplinarity in designing slags which can efficiently absorb macro-and micro-inclusions from different steels and at the same time act as protective cover against reoxidation and thermal losses. The final conclusion was that slag optimization is a challenging issue on which favorable metallurgical and thermal properties should be combined with long-lasting effect during sequential casting operation.

Physical Modeling of Mold Slag Entrainment in Continuous Steel Casting Mold with Consideration the Impact of Mold Powder Layer

“…Molten slags are widely used in process of manufacturing steel semi‐finished products, including the process of primary steelmaking, secondary steelmaking, and continuous steel casting (CSC) . In industrial conditions, the slag emulsification (called also slag entrainment) may occur at each of the above mentioned stages.…”

Influence of Reoxidation in Tundish on Inclusion for Ca‐Treated Al‐Killed Steel

“…Too much base oxides like FeO and MnO will consume [Al]s in steel, resulting in the loss of [Al]s and pick up of tiny Al 2 O 3 ‐rich inclusions and T.O. It also can be seen that Al 2 O 3 in flux increases from 26.58 to 33.16%, this is mainly due to the large “Al 2 O 3 capacity” of the original flux which has the features of both low melting (1693 K) and high basicity . This kind of flux readily absorbs Al 2 O 3 inclusions generated by reoxidation.…”

Improving Cleanliness of 16MnCrS5 Case Hardening Steels by Optimized Active Tundish Flux

“…Several studies to develop better covering slags for tundishes have been performed to absorb non‐metallic inclusions from steel. For effective removal of inclusions, basic fluxes are preferred . Basic slags have higher capacity to absorb alumina inclusions from steel than acid slags and the dissolution rate of Al 2 O 3 and MgO · Al 2 O 3 has been reported to increase with increasing slag basicity.…”

“…For effective removal of inclusions, basic fluxes are preferred . Basic slags have higher capacity to absorb alumina inclusions from steel than acid slags and the dissolution rate of Al 2 O 3 and MgO · Al 2 O 3 has been reported to increase with increasing slag basicity. The dissolution rate has also found to be greater in the presence of high thermodynamic driving force between slags and inclusions, that is, the difference in concentration between the saturation and the bulk composition for the dissolving species .…”