Weathering steel for coastal use

摘要

Weathering steels are used for steel structures to minimize costs for maintenance. However, in environments rich in airborne salt such as coastal areas, protective rust layers to reduce the corrosion rates are hardly formed on conventional weathering steels because of Cl{sup}-. New weathering steels for coastal use, whose basic chemical composition is 1.5%Ni-0.3%Mo-Fe, were developed. They showed higher corrosion resistance than JIS SMA in exposure tests in coastal environments. It is suggested that enrichment of Cl{sup}- at the steel/rust interface is prevented because the rust layer is densified and given cationic selectivity by adding Ni and Mo.