The rust that develops seals the surface by creating a protective layer preventing further corrosion and reducing the amount of glare that can be found on standard metals. This process reduces the amount of maintenance that is required whilst simultaneously increasing the lifespan of the material.
Weathering steel is an alloy of copper, nickel, and chromium, and this is what gives the steel a high level of resistance to atmospheric corrosion. For other types of steel, moisture and air can cause them to rust at varying rates which provide no protection to the material. This type of rust is extremely porous and can fall off the material over time.
Weathering steel still undergoes the initial rusting process, but the alloying elements create a consistent and stable layer of rust that adheres to the material. This rust layer provides protection against further encounters with moisture and air. The corrosion resistance of this metal ensures that it has a long lifetime, making weathering steel an economic choice for the construction industry.