The initial rust (flash rust) is a bright orange color on both weathering steel and ordinary carbon steel. However, on weathering steel, years of wet-dry cycling results in a compact, amorphous layer of various oxide products that typically convey a red-orange/brown appearance. Utilizing the steel raw, it takes about 8-10 years of natural weathering to develop the rust structure that is common on well-aged weathering steels. In the initial years, an oxide layer may be in place, although the protective nature of the coating itself is not yet fully active. Over decades, the oxide coating typically changes from a “rusty” red-orange to a dark purple-brown patina.
If managed in a controlled environment, various colors can be brought out through physical and chemical processes. Below are close-up shots of the range of colors and textures we have brought out of the modern CORTEN material; Weathering Steel (ASTM HSLA A588 & A606). We can manage the color range that is desired out of your weathering steel application, but it is important to remember that weathering steel supplies a ‘living’ finish that continues to evolve around the ambient environmental conditions and exposure.
To learn more about the nuances of weathering steel (corten), check out our Science page
To request digital sample shots for architectural renderings, please contact stittj@distressedmetals.com