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e. A metal (from Ancient Greek μέταλλον (métallon) 'mine, quarry, metal') is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically ductile (can be drawn into wires) and malleable (they can be hammered into thin sheets).
The chemical elements can be broadly divided into metals, metalloids, and nonmetals according to their shared physical and chemical properties. All metals have a shiny appearance (at least when freshly polished); are good conductors of heat and electricity; form alloys with other metals; and have at least one basic oxide.
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- Definitions and Related Materials
- Material Properties
- Production
- History
- Industry
- Recycling
- Contemporary
- Uses
- References
- Further Reading
The noun steel originates from the Proto-Germanic adjective stahliją or stakhlijan 'made of steel', which is related to stahlaz or stahliją'standing firm'. The carbon content of steel is between 0.02% and 2.14% by weight for plain carbon steel (iron-carbon alloys). Too little carbon content leaves (pure) iron quite soft, ductile, and weak. Carbon c...
Origins and production
Iron is commonly found in the Earth's crust in the form of an ore, usually an iron oxide, such as magnetite or hematite. Iron is extracted from iron ore by removing the oxygen through its combination with a preferred chemical partner such as carbon which is then lost to the atmosphere as carbon dioxide. This process, known as smelting, was first applied to metals with lower melting points, such as tin, which melts at about 250 °C (482 °F), and copper, which melts at about 1,100 °C (2,010 °F),...
Properties
The density of steel varies based on the alloying constituents but usually ranges between 7,750 and 8,050 kg/m3 (484 and 503 lb/cu ft), or 7.75 and 8.05 g/cm3(4.48 and 4.65 oz/cu in). Even in a narrow range of concentrations of mixtures of carbon and iron that make steel, several different metallurgical structures, with very different properties can form. Understanding such properties is essential to making quality steel. At room temperature, the most stable form of pure iron is the body-cent...
Heat treatment
There are many types of heat treating processes available to steel. The most common are annealing, quenching, and tempering. Annealing is the process of heating the steel to a sufficiently high temperature to relieve local internal stresses. It does not create a general softening of the product but only locally relieves strains and stresses locked up within the material. Annealing goes through three phases: recovery, recrystallization, and grain growth. The temperature required to anneal a pa...
When iron is smelted from its ore, it contains more carbon than is desirable. To become steel, it must be reprocessed to reduce the carbon to the correct amount, at which point other elements can be added. In the past, steel facilities would cast the raw steel product into ingots which would be stored until use in further refinement processes that ...
Ancient
Steel was known in antiquity and was produced in bloomeries and crucibles. The earliest known production of steel is seen in pieces of ironware excavated from an archaeological site in Anatolia (Kaman-Kalehöyük) and are nearly 4,000 years old, dating from 1800 BC. Steel was produced in Celtic Europe from around 800 BC, high-carbon steel was produced in Britain from 490-375 BC, and ultrahigh-carbon steel was produced in the Netherlands from the 2nd-4th centuries AD. The Roman author Horace ide...
Wootz and Damascus
Evidence of the earliest production of high carbon steel in India is found in Kodumanal in Tamil Nadu, the Golconda area in Andhra Pradesh and Karnataka, and in the Samanalawewa, Dehigaha Alakanda, areas of Sri Lanka. This came to be known as Wootz steel, produced in South India by about the sixth century BC and exported globally. The steel technology existed prior to 326 BC in the region as they are mentioned in literature of Sangam Tamil, Arabic, and Latin as the finest steel in the world e...
Modern
Since the 17th century, the first step in European steel production has been the smelting of iron ore into pig iron in a blast furnace. Originally employing charcoal, modern methods use coke, which has proven more economical.
The steel industry is often considered an indicator of economic progress, because of the critical role played by steel in infrastructural and overall economic development.In 1980, there were more than 500,000 U.S. steelworkers. By 2000, the number of steelworkers had fallen to 224,000. The economic boom in China and India caused a massive increase ...
Steel is one of the world's most-recycled materials, with a recycling rate of over 60% globally;in the United States alone, over 82,000,000 metric tons (81,000,000 long tons; 90,000,000 short tons) were recycled in the year 2008, for an overall recycling rate of 83%. As more steel is produced than is scrapped, the amount of recycled raw materials i...
Carbon
Modern steels are made with varying combinations of alloy metals to fulfill many purposes. Carbon steel, composed simply of iron and carbon, accounts for 90% of steel production. Low alloy steel is alloyed with other elements, usually molybdenum, manganese, chromium, or nickel, in amounts of up to 10% by weight to improve the hardenability of thick sections. High strength low alloy steelhas small additions (usually < 2% by weight) of other elements, typically 1.5% manganese, to provide additi...
Alloy
Stainless steels contain a minimum of 11% chromium, often combined with nickel, to resist corrosion. Some stainless steels, such as the ferritic stainless steels are magnetic, while others, such as the austenitic, are nonmagnetic.Corrosion-resistant steels are abbreviated as CRES. Alloy steels are plain-carbon steels in which small amounts of alloying elements like chromium and vanadium have been added. Some more modern steels include tool steels, which are alloyed with large amounts of tungs...
Standards
Most of the more commonly used steel alloys are categorized into various grades by standards organizations. For example, the Society of Automotive Engineers has a series of grades defining many types of steel. The American Society for Testing and Materials has a separate set of standards, which define alloys such as A36 steel, the most commonly used structural steel in the United States. The JISalso defines a series of steel grades that are being used extensively in Japan as well as in develo...
Iron and steel are used widely in the construction of roads, railways, other infrastructure, appliances, and buildings. Most large modern structures, such as stadiums and skyscrapers, bridges, and airports, are supported by a steel skeleton. Even those with a concrete structure employ steel for reinforcing. It sees widespread use in major appliance...
Bibliography
1. Ashby, Michael F.; Jones, David Rayner Hunkin (1992). An introduction to microstructures, processing and design. Butterworth-Heinemann. 2. Barraclough, K. C. (1984). Steel before Bessemer: I Blister Steel: the birth of an industry. London: The Metals Society. 3. Bugayev, K.; Konovalov, Y.; Bychkov, Y.; Tretyakov, E.; Savin, Ivan V. (2001). Iron and Steel Production. The Minerva Group, Inc. ISBN 978-0-89499-109-7. 4. Davidson, H. R. Ellis (1994). The Sword in Anglo-Saxon England: Its Archae...
Mark Reutter, Making Steel: Sparrows Point and the Rise and Ruin of American Industrial Might. University of Illinois Press, 2005.Duncan Burn, The Economic History of Steelmaking, 1867–1939: A Study in Competition Archived 2012-07-26 at the Wayback Machine. Cambridge University Press, 1961.Harukiyu Hasegawa, The Steel Industry in Japan: A Comparison with Britain Archived 2012-04-18 at the Wayback Machine. Routledge, 1996.J.C. Carr and W. Taplin, History of the British Steel Industry Archived 2012-07-29 at the Wayback Machine. Harvard University Press, 1962.This page lists metals, with subdivisions for alloys and specialised subsets of metal and metal-based compounds.
Bibliography. Further reading. Iron. This article is about the metallic element. For other uses, see Iron (disambiguation). Iron is a chemical element; it has symbol Fe (from Latin ferrum 'iron') and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table.
Physical properties. See also. References. Transition metals in the periodic table. In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded.
Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in sea water, aqua regia, and chlorine .
