The National Pavilion of the Grand Duchy of Luxembourg in the 2010 World Expo in Shanghai, the main building exterior of the pavilion is rust-colored, because the building materials are a special steel called weathering steel. Weathering steel is also called Cowton Steel. It is special in that it is exposed to the natural environment. With the action of air and rain, the surface of the steel will automatically form a corrosion-resistant protective layer without the need for painting protection. The life of the material is 80. More than a year.