FAQ: Does Climate Impact the Rate Weathering Steels Form a Patina?

weathering steel office building

FAQ: Does Climate Impact the Rate Weathering Steels Form a Patina?

Weathering steel, commonly referred to as corten steel, is the only type of steel that does not require paint or a sealant to protect it from atmospheric corrosion. In fact, weathering steels are intentionally manufactured to provide this resistance to atmospheric corrosion as well as enhanced yield and tensile strength properties. 

Just like standard steels, weathering steels are silver in their original state. But, when exposed to outdoor elements, weathering steels naturally develop a stable patina layer, which serves as a corrosion-resistant barrier. This patina prevents further access of oxygen, moisture and other pollutants while regenerating continuously as it is subjected to elements, such as humidity, rain, snow, etc.  

Many builders and architects select weathering steel because of these practical benefits in addition to the aesthetically-pleasing patina. As a weathering steel distributor, we’re often asked if climate impacts the rate at which weathering steels form a patina. 

Does climate impact the rate in which weathering steels form a patina?

Yes, the rate at which the protective patina forms varies and depends on the climate the steel resides in. In our experience as a high-strength weathering steel distributor, we’ve found that the patina forms quicker when the steel is exposed to more cycles of wet and dry weather. In more consistent (mostly dry or mostly wet) weather environments, it can take longer for the patina to form. 

For instance, in more humid climates (like Alabama), the weathering process tends to occur within 6-8 months, but in harsher, dryer climates (like Arizona) the patina develops at a much slower rate. The color and texture of the patina ranges from a lighter orange to a deeper orange-brown and is constantly evolving. 

In a previous blog, we documented how the patina developed on two samples of weathering steel over the course of 6 months in Pelham, Alabama. You can also check out how the patina has evolved in these photos of our office building, which is built almost entirely out of weathering steel. 

Though weathering steels cannot be purchased from mill manufacturers “pre-rusted,” some companies offer pre-rusting processes for weathering steels if an accelerated patina is considered critical to the customer’s application. 

Contact Central Steel Service for more weathering steel information

Do you have more questions about weathering steel? Contact one of our experienced sales associates. As a trusted supplier of weathering steel, we are committed to providing customers with an exceptional level of service to make your buying experience easy.