Effects of Structure and Reactivity of Carbonaceous Materials on Melting Behaviour of Mold Powders for Continuous Casting of Steel

摘要

Melting behaviour is a critical index in the selection of mold powders for the optimization of continuous casting. At the present time it is accepted that for a given mineralogical composition of mold powder, the carbon type, amount and particle size primarily determine the melting behaviour. However, there is no evidence in the literature that any attention has been given to the investigation of the relative amounts of amorphous and crystalline structures present in the carbonaceous materials together with their combustion reactivity and the correlation of these parameters with melting behaviour. To investigate these aspects, a novel approach has been employed that involves quantitative X-ray diffraction analysis (QXRDA), high-resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FESEM), evaluation of combustion reactivity using a fixed bed reactor, and determination of combustion temperature of carbon using a multiphase gas analyzer, the melting behaviour of mold powder using pan box tests and high temperature cell microscopy. The research has been directed towards evaluation of the chemical structure and surface characteristics of different carbonaceous materials. The relationship between these parameters and the combustion reactivity of the different materials was then determined and this information subsequently correlated with the melting behaviour of different mold powders.