American Standard A588 bridge weathering steel manufacturers

A588 Alloying Elements of Weathering Steel for Bridges

C:≤0.19 Cu:0.25~0.4 V:0.02~0.1 Si:0.3~0.65 Mn:0.8~1.25 P:≤0.03 S:≤0.03 Ni:≤0.4 Cr:0.4~0.65

A588 bridge weathering steel plate forms a protective layer on the surface of the metal substrate through the alloying of Cu, P, Cr, Ni, etc., and has high atmospheric corrosion resistance.

Weathering steel requires no maintenance corrosion protection in most environments. However, the corrosion rate of weathering steels may not be satisfactory under severe service conditions because no protective patina has formed on the steel surface. In this hostile environment, conventional weathering steels do not provide adequate corrosion resistance.

Regular and high performance weathering steels perform well except under prolonged wet conditions and when chlorides are naturally deposited on the steel (i.e. in coastal areas) or in snow belt areas where deicing salts are heavily used. The reason for this behavior is related to weathering It is related to the formation or non-formation of a protective oxide or oxyhydroxide layer on the steel surface.

Forming such a layer on weathering steel requires frequent drying so that the nanophase goethite can form in the absence of moisture. The nanophase goethite constitutes the main impermeable layer on the weathering steel. The presence of an unknown level of chloride in the hydroxide surface layer inhibits the formation of nanophase goethite in favor of the formation of hematite and/or maghemite. This is why coastal and de-icing salt environments are not happy with weathering steel.