Impiego degli acciai con migliorata resistenza alla corrosione atmosferica (Cor-Ten) per strutture in acciaio Use of weather resistant steels (Cor-Ten) for steel structures

Weathering steels, or Cor-Ten steels, are low alloy structural steels that guarantee similar mechanical characteristics compared to common carbon steels for structural uses, but with an improved resistance to corrosion when exposed to low-moderate aggressive atmospheres (rural, urban and mild industrial) and to wet/dry cycles. This characteristic is associated to the formation, over time, of a protective patina, a dense and adherent layer of corrosion products, on the steel surface that reduces its consumption, induced by corrosion, to few micrometers per year. To obtain the advantages related to the longer service life that these steels can guarantee, however, it is necessary to know the conditions that lead to the correct protective patina formation. The incorrect use of these steels can lead to make null the benefits associated with their use. In this paper, initially this type of steels is described and, afterwards, guidelines for their correct use are provided.