At one time ASTM A588 steel "self weathering" was used here on bridges over waterways where future painting and paint removal eviromental concerns exist. It contains a small amount of copper that forms a patina that helps protect itself when allowed to oxidize. It is more prone to cracking than A36 but probably not a big deal for your application. Many standard structural shapes are commonly available. Special welding rods are also required and readily available as well. The problem is that the protective layer is formed during the wet and dry cycling. The protective layer cannot form underwater on self weathering steel. It can be painted with a good quality marine coating on what will be below surface but the coating may be comprimised during the installation process. A good painting system we use is an organic zinc primer, and epoxy intermediate coat followed by a urethane top coat.



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