This study proposed a new methodology to optimize the fuel use in a walking beam reheating furnace that uses swirl burners in the soaking zone through mathematical simulation. Likewise, the radiative effect of the WSGGM model over the heating and thermal gradient of the slab was analyzed, as well as its thermal implications of using swirl and diffusion burners. The model was validated with experimental temperatures obtained inside the furnace by using 16 thermocouples, and they were compared with those in the simulation, reaching an average error of 3.19%. This methodology has allowed the proposal of new operating conditions in fuel management, making the combustion process more efficient with an average saving of 5,067,360 kg of methane annually, representing 9% of the plant’s current use. This optimization process would mean substantial economic savings for the industry and would also be reflected in a significant decrease of greenhouse gases with adverse effects on the planet.