Weathering steel products are commonly used in the painted condition for constructions such as steel boats and freight containers for sea transport. In
continuous contact with water, the corrosion rate hardly differs from that of general structural steels, but the paint life on weathering steels can be up to twice as long. This is because the propagation of corrosion under local damage on painted surfaces is markedly slower than on ordinary steel. In this way, the appearance of painted structures remains trim much longer and the lifetime cost of shot blasting
and repainting is halved.Rautaruukki Steel manufactures weathering steels
to both Standard EN 10155 and under the brand name COR-TEN. The steel grades S355JOWP, S355J2JOWP and COR-TEN A have the best weathering properties. Because of the phosphorus used as an alloying element, however, the impact strength of these steel grades is lower than that of other weathering steels. These weathering steels are best suited for sheet steel structures that are not under the risk of brittle fracture.