<p>This work presents calculations of velocity and temperature fields in a H₂–N₂ atmosphere that counterflows a steel strip moving in a continuous strip annealing furnace. The mathematical model is based on the numerical solution of the differential equations of conservation of mass, momentum, and energy, subjected to appropriate boundary conditions. The model includes vertical and horizontal regions in the furnace but excludes the zone of direct flame heating. The net heat flux in the sheet surface is the result of the received radiation heat flux from the furnace wall and the removed convective heat flux by the flowing gas. The model results are compared with estimated values from empirical correlations reported in terms of Nusselt number. Model calculations include the effect of variables such as radiation heat transfer and sheet velocity. Based on the model results, a new correlation is proposed for the heat transfer coefficient in continuous heating furnaces.</p> Graphical abstract <p></p>