Device for heating steel products

Apparatus for heating steel products, comprising:

• a heating chamber which extends between an inlet and an outlet, inside of which there are defined, in sequence, an inlet zone, an intermediate zone and an outlet zone,
• a plane of advance in said heating chamber defined by the alternation of fixed support elements and mobile support elements supported respectively by fixed bearing elements and mobile bearing elements,
• feed and extraction means provided with respective feed and extraction rollers respectively associated with said inlet and said outlet,
• heating and/or combustion members disposed both above and also below said plane of advance,
• the fixed and mobile support elements, the fixed and mobile bearing elements and the feed and extraction rollers are made of a metal superalloy comprising at least as main components, nickel and chromium, at least 70% and up to 90% of their composition, and a combination of further components between 10% and 30%, wherein the further components complete the chemical composition of the superalloy and are comprised amongst aluminum, iron, tantalum, zirconium, vanadium, magnesium, calcium, carbon, boron, phosphorus, molybdenum, tungsten, titanium, silicon, niobium, manganese, cobalt,
• wherein making said fixed and mobile support elements, said fixed and mobile bearing elements and said feed and extraction rollers with said superalloy allows to not have liquid-based cooling means inside said heating chamber,
• wherein the fixed and mobile support elements, the fixed and mobile bearing elements and the feed rollers present in said inlet zone are made of a first metal superalloy, the fixed and mobile support elements and the fixed and mobile bearing elements present in said intermediate zone are made of a second metal superalloy, while the fixed and mobile support elements, the fixed and mobile bearing elements and the extraction rollers present in said outlet zone are made of a third metal superalloy, wherein said first metal superalloy has an overall content of nickel and chromium lower than that of the second metal superalloy and the second metal superalloy has a nickel and chromium content lower than that of the third metal superalloy.