When it’s exposed to the elements, this steel forms a thin shell of rust that shields the interior from corrosion. It’s also known as weathering steel. Low carbon content makes it very weldable. Since you don’t need to paint this steel to prevent corrosion, it requires less maintenance than other types of steel—it’s commonly used in bridges, buildings, and fencing. It’s comparable to Corten steel. With a yield strength of 50,000 psi, this steel is stronger than A36 and other low-carbon steels. It can also be surface hardened with heat treating for added wear resistance.