Weathering Steel, also referred to as Cor-Ten steel, is a group of steel alloys that were developed to eliminate the need for painting, and form a stable rust-like appearance if exposed to weather for several years. The chemical composition of these steels includes small amounts of copper, nickel, chromium, and phosphorus. When Corten steel is exposed to the weather, an oxide layer forms on its surface that protects the steel underneath from further corrosion. This allows it to develop a uniform appearance and be used without painting, leading to lower long-term maintenance costs compared to more conventional steels.

Increased Use in Infrastructure Projects

Transportation infrastructure projects have helped drive the growing demand for Corten steel. Its corrosion-resistant properties make it well-suited for bridges and other structures where maintenance painting would be difficult and costly over the lifetime of the project. Many highway departments prefer the use of Weathering Steel for new steel bridge construction as it eliminates the need to invest resources in painting and re-painting over time. In addition, Corten steel is seeing more widespread use for things like signs, noise barriers, and retaining walls alongside highways. Railroads are also increasing their use of Corten steel for things like signal masts, bridge structures, and retaining walls near tracks due to its low maintenance needs.

Offshore Oil and Gas Industry Adoption

Corten steel has also found an important role in the offshore oil and gas industry. Its weathering characteristics make it ideal for use on offshore oil rigs and production platforms. These harsh, marine environments subject steel to more rapid corrosion compared to land-based locations. Using Corten steel limits long-term maintenance needs and avoids problems with more traditional carbon steels like rusting and the risks of paint peeling. It maintains a uniform appearance even after years of exposure to saltwater, waves, and other weather conditions present offshore. This has led to rapidly growing demand from offshore platform and rig fabricators.

Construction Applications Globally

Weathering Steel is being more commonly used in construction applications worldwide beyond just infrastructure projects. Due to its natural appearance when exposed to weather, architects are specifying it more frequently for projects where they want an unpainted, rusted metal look. Examples include metal roofs, architectural panels, exterior siding, sculptures, and railings for buildings. In many parts of Europe and Asia, Corten steel is a popular material choice due to its lower total cost of ownership from reduced long-term maintenance. It has also gained popularity in certain construction niches in the Middle East, South America, Australia, and other where infrastructure and industrial development is occurring rapidly.