Stainless steel as the common ferritic and austenitic stainless steels due to their low chromium content. Duplex stainless steels have a mixed microstructure of austenite and ferrite, the aim usually being to produce a 50/50 mix, although in commercial alloys the ratio may be 40/60. They are characterized by high chromium (19–32%) and molybdenum (up to 5%) and lower nickel contents than austenitic stainless steels. Duplex stainless steels have roughly twice the strength compared to austenitic stainless steels. Their mixed microstructure provides improved resistance to chloride stress corrosion cracking in comparison to austenitic stainless steels Types 304 and 316. The properties of
Stainless steel both the Petronas Twin Towers and the Jin Mao Building, two of the world's tallest skyscrapers. The Parliament House of Australia in Canberra has a stainless steel flagpole weighing over . The aeration building in the Edmonton Composting Facility, the size of 14 hockey rinks, is the largest stainless steel building in North America. La Geode in Paris is a nearly spherical building. The dome is composed of 6433 polished stainless steel equilateral triangles that form the sphere that reflects the sky. Stainless steel is quite frequently used for pedestrian and for road bridges. Product forms are tubes (Helix bridge),