Relatively robust predictive models for the steel reheating processes are crucial for efficient control and optimisation of reheat furnace operation while ensuring good quality of the heated products. This paper describes the development of a two-dimensional (2D) mathematical model, based on the zone method of radiation analysis, which is capable of simulating the thermal performance of a walking-beam reheating furnace, such as the temperature distribution inside the furnace and the heated stock. The models were initially validated using experimental data supplied by Swerea MEFOS, Sweden. The validated models were further used to investigate changes in the furnace operating conditions, such as production rates and production delay. The results show that the model predictions are in agreement with the measured data and that the model can reasonably respond to the changes in different operating conditions. The developed model has the potential to predict durations of furnace operation of a thousand times faster than the actual run time, and it also demonstrates the feasibility and practicality for incorporation into a model based furnace control system.