Following the casting process, slabs or billets are transported to the hot rolling mill and heated to rolling temperature, e.g. in walking-beam furnaces or pusher-type furnaces. A pusher-type furnace operates semi-continuously and is characterized by high throughput rates and maximum heat transfer capacity. Cold slabs are pushed into the furnace where they initially slide on carrier rails, then on an equalizing surface to the discharge end. Typical issues concerning the heating process are the slab heating rate, the number of burners required and the influence of the carrier rails on the skid marks, i.e. the local temperature distribution, in the slab.