ASTM A606/A606M-09a Atmospheric pressure corrosion-resistant low-alloy high-strength steel hot-rolled and cold-rolled steel sheets and strips are made of ordinary carbon steel with small additions of copper, nickel and other corrosion-resistant elements. After adding phosphorus, copper, chromium, nickel and other trace elements to the steel, a dense and firm protective film is formed on the steel surface to prevent the inward diffusion and development of rust, protect the rusted substrate layer, and slow down its corrosion. Speed The amorphous spinel oxide layer with a thickness of about 50-100 μm formed between the rust layer and the substrate is dense and has good adhesion to the substrate metal. Due to the existence of this dense oxide film, it blocks oxygen and oxygen in the atmosphere. The penetration of water into the steel matrix slows down the in-depth development of corrosion on the steel and greatly improves the atmospheric corrosion resistance of the steel. Weathering stee…