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Stainless steel : 276 is a group of iron-based alloys that contain a minimum of approximately 11% chromium,: 3 a composition that prevents the iron from rusting, as well as providing heat-resistant properties.: 3 Different types of stainless steel include the elements carbon (from 0.03% to greater than 1.00%), nitrogen, aluminium, silicon, sulfur, titanium, nickel, copper, selenium, niobium, and molybdenum.: 3 Specific types of stainless steel are often designated by a three-digit number, e.g., 304 stainless . Stainless steel's resistance to ferric oxide formation results from the presence of chromium in the alloy, which forms a passive film that protects the underlying material from corrosion attack, and can self-heal in the presence of oxygen.: 3 Corrosion resistance can be increased further, by: The addition of nitrogen also improves resistance to pitting corrosion and increases mechanical strength. Thus, there are numerous grades of stainless steel with varying chromium an...

The invention of stainless steel followed a series of scientific developments, starting in 1798 when chromium was first shown to the French Academy by Louis Vauquelin. In the early 1800s, James Stoddart, Michael Faraday, and Robert Mallet observed the resistance of chromium-iron alloys ("chromium steels") to oxidizing agents. Robert Bunsen discovered chromium's resistance to strong acids. The corrosion resistance of iron-chromium alloys may have been first recognized in 1821 by Pierre Berthier, who noted their resistance against attack by some acids and suggested their use in cutlery. In the 1840s, both Sheffield steelmakers and Krupp were producing chromium steel with the latter employing it for cannons in the 1850s. In 1861, Robert Forester Mushet took out a patent on chromium steel. These events led to the first production of chromium-containing steel by J. Baur of the Chrome Steel Works of Brooklyn for the construction of bridges. A U.S. Patent for the product was iss...

This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( March 2020 ) (Learn how and when to remove this template message) There are five main families, which are primarily classified by their crystalline structure: austenitic, ferritic, martensitic, duplex, and precipitation hardening. Austenitic stainless steel edit Austenitic stainless steel is the largest family of stainless steels, making up about two-thirds of all stainless steel production (see production figures below). They possess an austenitic microstructure, which is a face-centered cubic crystal structure. This microstructure is achieved by alloying steel with sufficient nickel and/or manganese and nitrogen to maintain an austenitic microstructure at all temperatures, ranging from the cryogenic region to the melting point. Thus, austenitic stainless steels are not hardenable by heat treatment ...

This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( March 2020 ) (Learn how and when to remove this template message) Unlike carbon steel, stainless steels do not suffer uniform corrosion when exposed to wet environments. Unprotected carbon steel rusts readily when exposed to a combination of air and moisture. The resulting iron oxide surface layer is porous and fragile. In addition, as iron oxide occupies a larger volume than the original steel, this layer expands and tends to flake and fall away, exposing the underlying steel to further attack. In comparison, stainless steels contain sufficient chromium to undergo passivation, spontaneously forming a microscopically thin inert surface film of chromium oxide by reaction with the oxygen in the air and even the small amount of dissolved oxygen in the water. This passive film prevents further corrosion b...

Physical properties edit Electricity and magnetism edit Like steel, stainless steels are relatively poor conductors of electricity, with significantly lower electrical conductivity than copper. In particular, the electrical contact resistance (ECR) of stainless steel arises as the result of the dense protective oxide layer, and limits its functionality in applications as electrical connectors . Copper alloys and nickel coated connectors tend to exhibit lower ECR values, and are preferred materials for such applications. Nevertheless stainless steel connectors are employed in situations with ECR poses a lower design criteria and corrosion resistance is required, for example in high temperatures and oxidizing environments . Magnetic properties edit Martensitic and ferritic stainless steels are magnetic. Ferritic steel consists of ferrite crystals, a form of iron with up to 0.025% carbon. Due to its cubic crystalline structure, ferritic steel only absorbs a small amount of carbon, which...

This section does not cite any sources . Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. ( March 2020 ) (Learn how and when to remove this template message) Standard mill finishes can be applied to flat rolled stainless steel directly by the rollers and by mechanical abrasives. Steel is first rolled to size and thickness and then annealed to change the properties of the final material. Any oxidation that forms on the surface (mill scale) is removed by pickling, and a passivation layer is created on the surface. A final finish can then be applied to achieve the desired aesthetic appearance. The following designations are used to describe stainless steel finishes: No. 0: Hot-rolled, annealed, thicker plates No. 1: Hot-rolled, annealed and passivated No. 2D: Cold rolled, annealed, pickled and passivated No. 2B: Same as above with additional pass through highly polished rollers No. 2BA: Bright annealed (BA o...

This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( March 2020 ) (Learn how and when to remove this template message) A wide range of joining processes are available for stainless steels, though welding is by far the most common. Welding stainless steels edit The ease of welding largely depends on the type of stainless steel used. Austenitic stainless steels are the easiest to weld by electric arc, with weld properties similar to those of the base metal (not cold-worked). Martensitic stainless steels can also be welded by electric-arc but, as the heat-affected zone (HAZ) and the fusion zone (FZ) form martensite upon cooling, precautions must be taken to avoid cracking of the weld. Post-weld heat treatment is almost always required while preheating before welding is also necessary in some cases. Electric arc welding of Type 430 ferritic stainless steel ...

This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( March 2020 ) (Learn how and when to remove this template message) Production process edit Most of the world's stainless steel production is produced by the following processes: Electric arc furnace (EAF): stainless steel scrap, other ferrous scrap, and ferrous alloys (Fe Cr, Fe Ni, Fe Mo, Fe Si) are melted together. The molten metal is then poured into a ladle and transferred into the AOD process (see below). Argon oxygen decarburization (AOD): carbon in the molten steel is removed (by turning it into carbon monoxide gas) and other compositional adjustments are made to achieve the desired chemical composition. Continuous casting (CC): the molten metal is solidified into slabs for flat products (a typical section is 20 centimetres (8 in) thick and 2 metres (6.6 ft) wide) or blooms (sections vary ...

This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( March 2020 ) (Learn how and when to remove this template message) Architecture edit The use of stainless steel in buildings can be both practical and aesthetic. In vogue during the Art Deco period, the most famous use of stainless steel can be seen in the upper portion of the Chrysler Building. Thanks to its durability, many of these buildings have retained their original appearance. Stainless steel is used in the construction of modern buildings, such as the exterior of the Petronas Twin Towers and the Jin Mao Building. The Parliament House of Australia in Canberra has a stainless steel flagpole weighing over 220 metric tons (240 short tons). The largest stainless steel building in North America is the aeration building in the Edmonton Composting Facility. La Geode in Paris has a dome composed of 643...

This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( March 2020 ) (Learn how and when to remove this template message) Life cycle cost (LCC) calculations are used to select the design and the materials that will lead to the lowest cost over the whole life of a project, such as a building or a bridge. The formula, in a simple form, is the following: citation needed LCC = AC + IC + ∑ n = 1 N OC ( 1 + i ) n + ∑ n = 1 N LP ( 1 + i ) n + ∑ n = 1 N RC ( 1 + i ) n {\displaystyle {\text{LCC}}={\text{AC}}+{\text{IC}}+\sum _{n=1}^{N}{\frac {\text{OC}}{(1+i)^{n}}}+\sum _{n=1}^{N}{\frac {\text{LP}}{(1+i)^{n}}}+\sum _{n=1}^{N}{\frac {\text{RC}}{(1+i)^{n}}}} where LCC is the overall life cycle cost, AC is the acquisition cost, IC the installation cost, OC the ope...

This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( March 2020 ) (Learn how and when to remove this template message) The average carbon footprint of stainless steel (all grades, all countries) is estimated to be 2.90 kg of CO 2 per kg of stainless steel produced, of which 1.92 kg are emissions from raw materials (Cr, Ni, Mo); 0.54 kg from electricity and steam, and 0.44 kg are direct emissions (i.e., by the stainless steel plant). Note that stainless steel produced in countries that use cleaner sources of electricity (such as France, which uses nuclear energy) will have a lower carbon footprint. Ferritics without Ni will have a lower CO 2 footprint than austenitics with 8% Ni or more. Carbon footprint must not be the only sustainability-related factor for deciding the choice of materials: over any product life, maintenance, repairs or early end of l...

Stainless steel nanoparticles have been produced in the laboratory. These may have applications as additives for high-performance applications. For example, sulfurization, phosphorization, and nitridation treatments to produce nanoscale stainless steel based catalysts could enhance the electrocatalytic performance of stainless steel for water splitting.

Welding edit There is extensive research indicating some probable increased risk of cancer (particularly lung cancer) from inhaling welding fumes while welding stainless steel. Stainless steel welding is suspected of producing carcinogenic fumes from cadmium oxides, nickel, and chromium. According to Cancer Council Australia, "In 2017, all types of welding fumes were classified as a Group 1 carcinogen." Cooking edit Stainless steel is generally considered to be biologically inert. However, during cooking, small amounts of nickel and chromium leach out of new stainless steel cookware into highly acidic food. Nickel can contribute to cancer risks—particularly lung cancer and nasal cancer. However, no connection between stainless steel cookware and cancer has been established.