Building contractors, construction companies, and architects utilize various materials to create beautiful and durable buildings for you. Current building designs feature different metal parts. For instance, metal claddings are commonly used in construction projects. Manufacturers offer various cladding systems, including aluminum composite panels, steel siding, copper, etc. One of these functional materials is weathering steel, which has unique features and characteristics. In this article, you will learn about the available CORTEN weathering steel grades and their specifications.

What is Weathering Steel or CORTEN Steel?

CORTEN Steel, or weathering steel, is one of the current most popular metal materials that is used in the building industry for different applications and purposes. This particular metal naturally forms an oxidized finish with orange accents, making it highly desirable for architectural applications.

CORTEN Weathering Steel is a group of steel alloys that have been developed over time to help designers and architects create beautiful and long-lasting buildings.

Weathering steel is highly resistant to corrosion, making it the best material among other steel alloys. This characteristic of CORTEN steel is because of its rustic layer that is created after being exposed to humidity and air over the years.

Additionally, with the CORTEN weathering steel grades, you do not need to worry about maintenance and painting during its lifespan, extending to more than 40 years. In a simple way, weathering steel panels rust, and the rust layer creates a beautiful protective coating for your cladding system.

Best CORTEN Weathering Steel Grades

Metal materials manufacturers produce various CORTEN weathering steel grades that have different specifications. The best ones for ASTM specifications are:

  • A588 CORTEN Steel: Mostly used for cladding systems and structural shapes, plates, and bars.
  • A242 Weathering Steel: Perfect for covering steel plates through 4 centimeters in thickness.
  • A606-4 CORTEN: This weathering steel grade also covers steel sheets and coil.
  • A847 Steel: This grade is used for weathering steel tubes and pipes.
  • A871-65 CORTEN Weathering Steel: This grade also covers steel plates with a 65ksi minimum strength of yield.
CORTEN Steel Cladding

Advantages of CORTEN Weathering Steel

Let us tell you the advantages of CORTEN weathering steel panels that make them the perfect material for your next project.

CORTEN Weathering Steel Grades have Extensive Appeal

The corrosion-resistant characteristic of weather-resistant steel allows it to be used unpainted in all structural and architectural projects.

CORTEN is a Low-Maintenance Steel

The only maintenance that CORTEN steel requires is periodic inspection and cleaning, ensuring the structure performs the way it should. This steel is perfect for buildings that need minimum disruption.

Cost Benefits

Since weathering steel grades do not need additional paints or repainting during their lifespan, they decrease your material cost. Additionally, you do not need to spend money on labor or energy to clean them due to their low maintenance characteristics.

With CORTEN steel cladding panels, you will add value to the house. So, buying and using weathering steel is a perfect investment you can make.

CORTEN Provides Construction Speed

Since installing weathering steel panels is more straightforward than regular steel cladding systems, the construction time is lessened with these metal materials.

Weathering Steel Grades are Attractive

CORTEN Weathering steel’s unique and attractive appearance with its natural rustic finish blends perfectly with its surroundings and environment. The best thing about these weather-resistance steel panels is that their appearance even improves with age.

Weathering Steel is a Safe Construction Material

Health and safety problems are eliminated with weather-resistant steel panels since they are fire-proof and do not need to be painted with synthetic materials.

High-Temperature Advantages

CORTEN Weathering steel can decrease the oxidation loss of the standard steel panels at a temperature above four hundred degrees Celsius. At these temperatures, a beautiful patina forms on the panel’s surface. However, the performance improvement of weathering steel depends on the environmental conditions and heating cycle.

Can You Weld Weathering Steel Grades?

You may wonder if you can use CORTEN Weathering Steel grades for complex designs since your result will need a metal fabrication procedure. One of the most required fabrication systems is metal welding services. This fabrication method uses heat to melt and attach to pieces of metal. But, can you weld CORTEN steel tubes, pipes, or panels?

The answer is yes. Metal manufacturers can weld weathering steel by using the same flux combination as its grade so that the tensile strength of the welding rod or wire is consistent with the strength of the weathering steel.

The typical tensile strength of weathering steel grades is 68 to 78 KSI. SO, we recommend only welding A606-4 or A588 COREN steel grades together.

Note: Welding weather-resistant steel to other metal materials can react differently with other grades.

Can You Apply a Clear Coat to the CORTEN Weathering Steel Grades?

If you really want to apply a clear coat to your weathering steel panels, you should do it after the A606-4 and A588 have a perfect rustic or patina formed on the steel sheets.

If you apply it before the naturally generated rustic finish on the CORTEN surface, you should expect your clear coat to take off the patina or rustic finish.

Applying a clear coat to A606-4 and A588 weathering steel grades will change the color of your panel’s surface due to the additives that exist in your clear coat.

Unfortunately, we do not have any specific recommendations on materials for clear coating. So, it is better to check your local paint store and get their guidance since they are experts when it comes to different coating materials.

DEcorative Weathering Steel

How Long Will It Take to Develop the Rustic Finish on CORTEN Steel?

We cannot give you a specific timeline on how long the complete rustic or patina finish will take to form since multiple factors affect getting the orange-brown oxide finish. Those factors are:

  • Environment
  • Moisture
  • Weather
  • Humidity

However, it is good to know that A606-4 weathering steel grade develops the finish faster since it can go through dry and wet cycles. When this CORTEN grade gets wet, it starts forming the orange-brown oxide, and after it dries from the moisture, the natural rust will begin to develop into the panels.

Note: If you want your steel panels to form the rustic finish faster, there are some natural solutions that you can repeatedly apply to assist your steel in developing an attractive patina. For example, you can rinse your CORTEN cladding panels with water on a sunny day to create extra humidity.

How Long Will Your CORTEN Steel Last?

One of the reasons that made CORTEN steel a desired architectural material in the modern world is that it can last for a long. However, there is no exact answer to this question since it primarily depends on the environment and its installation process. For example, sealing CORTEN steel can extend its life span or decrease it.

Most of the construction projects that use bare cold-rolled weathering steel will last more than forty years without having any problems. Today’s manufacturers produce CORTEN steel panels that can even last longer than common ones.

Additionally, metal panels suppliers offer thin and thick weathering steel panels. If you want to increase the lifespan and longevity of your CORTEN panels, you should opt for heavier gauge sheets.

Does the CORTEN Steel Rusting Stop?

One of the exciting facts about CORTEN Weathering Steel is that it never completely stops rusting and developing patina. The process of creating a patina starts after you install the CORTEN panels. They eventually decrease and generate that point on the finish, acting as the protection layer for the main metal panels. As told, this layer prevents the boards from corrosion.

Research and laboratory analysis of the rust film formed on the weathering steel has shown that the alloying elements in the steel panels produced insoluble compounds that obstructed the pores at the interface. Hence, it never stops regenerating the rust.

With this said, your facility will always experience improvements in aesthetics and make it uniquely stand out in your neighborhood.

Can You Use CORTEN Weathering Steel for Decorative Applications?

One of the essential things about metal panels and materials in the construction industry is that they can be used for creating decorative elements in your home.

Since Corten Weathering steel is resistant to corrosion, safe, beautiful, and can last long, it is perfect for decorative applications such as gates and privacy screens.

Modern manufacturers offer beautiful decorative metal fence or ornamental metal fence panels that are made with weathering steel, and you can use them for your gardens and driveways or gates. So, with weather-resistant steel, you will create a beautiful and safe place for you and your family to live.