The role of mould fluxes in continuous casting-so simple yet so complex

The performance of mould fluxes in providing the optimum levels of lubrication and horizontal heat flux is relatively simple since they rely on only three properties, the viscosity and break temperature of the flux and the crystalline fraction developed in the slag film. These parameters can be readily calculated according to the mould dimensions, casting conditions and steel grade. It is only when the flux is used to combat other problems, such as those arising from turbulent metal flow (e.g. slag entrapment) that flux behaviour becomes complex and more difficult to understand. Some recent developments may help to combat problems associated with turbulent metal flow and free the flux to carry out its principal duties of providing optimum lubrication and horizontal heat flux.