A mathematical model of mould flux infiltration and heat transfer through the flux film has been developed. The model considers the effect of static pressure of molten steel, temperature dependency of flux viscosity and determination of liquid flux thickness with pressure gradient. Present model gives the results that agree well with actual plant data such as mould flux consumption, mould friction and the heat transfer. The results of the model give remarkable effect of static pressure of molten steel as follows: decrease of the static pressure causes increase of liquid and total flux film thickness, reduction of heat flux and decrease of friction force on solidified shell.