Steel its tensile strength and make the austenite form of the iron-carbon solution more stable, chromium increases hardness and melting temperature, and vanadium also increases hardness while making it less prone to metal fatigue. To inhibit corrosion, at least 11% chromium is added to steel so that a hard oxide forms on the metal surface; this is known as stainless steel. Tungsten slows the formation of cementite, keeping carbon in the iron matrix and allowing martensite to preferentially form at slower quench rates, resulting in high speed steel. On the other hand, sulfur, nitrogen, and phosphorus are considered contaminants that make
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),