Due to production conditions slabs cool before processing to the final product, re-heating ovens heat the slabs up again.
Subsequent heat treatment can change the material structure and characteristics of the slabs. The annealing process is one of several heat treatment steps. The material is heated in a controlled manner and - depending on the desired property - cooled at different speeds after a certain holding time. For this purpose, continuous but also discontinuous heat treatment furnaces of various types are used.
The energy input in the ovens is either electrically or by means of burners, with burner systems and burner position differing in the various ovens. In principle, burner systems with air/oxygen enrichment and oxyfuel burners have a higher thermal efficiency and other advantages over cold air burner systems.