What You Should Know About Weathering Steel

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What You Should Know About Weathering Steel


For those looking for low carbon steel with additional strength and more corrosion resistance than most low carbon grades, weathering steel is the way to go. At Wasatch Steel, we can provide you with this and any other types you’re in need of.

How can weathering steel help you, and what are some of its most common uses? Let’s take a look.


Weathering steel will typically have less than 0.3 percent carbon by weight, and there’s a purpose for this. This low carbon total helps it remain ductile and tough, while other alloying elements that are also added will help increase the strength and corrosion resistance. There are three key elements in weathering steel: Nickel, copper and chromium.

How it Works

Similar to other corrosion resistant steels, weathering steel resists rust formation – it will rust, but it will only do so on the outer surface. Rust does not penetrate any deeper, and the surface layer actively protects the steel from any further corrosion.

This is in contrast to plain carbon steel, where the rust layer that forms is porous and weak, and will break off and allow another layer of rust to form deeper in steel. In weathering steel, this cycle is stopped early, eliminating the need to coat weathering steel.

Grades and Uses

Some grades of weathering steel, such as COR-TEN A or COR-TEN B, are proprietary in nature. These are similar to the ASTM classifications A 242 and A 588.

Because weathering steel is able to outlast plain carbon steel outdoors, it’s regularly used on structures that are exposed. It doesn’t need to be constantly repainted and recoated, like plain steel. Areas it’s used include building and bridge construction – by the time the amount of corrosion would be unsafe on these products, the structure would have already exceeded design life for other reasons.

To learn more about weathering steel and how it can help you, or to find out about any of our other steel services, speak to the pros at Wasatch Steel today.