| definition |
- Any of various alloys based on iron containing carbon (usually 0.1-0.7 per cent) and often small quantities of other elements such as phosphorus, sulphur, manganese, chromium, and nickel. Steels exhibit a variety of properties, such as strength, machinability, malleability, etc., depending on their composition and the way they have been treated.
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| Abstract from DBPedia | Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant typically need an additional 11% chromium. Because of its high tensile strength and low cost, steel is used in buildings, infrastructure, tools, ships, trains, cars, machines, electrical appliances, weapons, and rockets. Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic. The interaction of the allotropes of iron with the alloying elements, primarily carbon, gives steel and cast iron their range of unique properties. In pure iron, the crystal structure has relatively little resistance to the iron atoms slipping past one another, and so pure iron is quite ductile, or soft and easily formed. In steel, small amounts of carbon, other elements, and inclusions within the iron act as hardening agents that prevent the movement of dislocations. The carbon in typical steel alloys may contribute up to 2.14% of its weight. Varying the amount of carbon and many other alloying elements, as well as controlling their chemical and physical makeup in the final steel (either as solute elements, or as precipitated phases), impedes the movement of the dislocations that make pure iron ductile, and thus controls and enhances its qualities. These qualities include the hardness, quenching behaviour, need for annealing, tempering behaviour, yield strength, and tensile strength of the resulting steel. The increase in steel's strength compared to pure iron is possible only by reducing iron's ductility. Steel was produced in bloomery furnaces for thousands of years, but its large-scale, industrial use began only after more efficient production methods were devised in the 17th century, with the introduction of the blast furnace and production of crucible steel. This was followed by the open-hearth furnace and then the Bessemer process in England in the mid-19th century. With the invention of the Bessemer process, a new era of mass-produced steel began. Mild steel replaced wrought iron. The German states saw major steel prowess over Europe in the 19th century. Further refinements in the process, such as basic oxygen steelmaking (BOS), largely replaced earlier methods by further lowering the cost of production and increasing the quality of the final product. Today, steel is one of the most commonly manufactured materials in the world, with more than 1.6 billion tons produced annually. Modern steel is generally identified by various grades defined by assorted standards organisations. The modern steel industry is one of the largest manufacturing industries in the world, but is one of the most energy and greenhouse gas emission intense industries, contributing 8% of global emissions. However, steel is also very reusable: it is one of the world's most-recycled materials, with a recycling rate of over 60% globally.鋼（はがね、こう、釼は異体字、英: steel）とは、炭素を400ppmから2パーセント程度含む鉄の合金。鋼鉄（こうてつ）とも呼ばれる。炭素のみを加えた炭素鋼と、ニッケル・クロムなどを加えた特殊鋼（合金鋼）の2種が存在する。純粋な鉄に比べ強靭で加工性に優れ、鉄の利用の大部分は鋼によって占められているため、鉄と鋼を合わせ鉄鋼（てっこう）とも呼ばれる。資源量が豊富で精錬しやすく、強靱であり加工もしやすい上に安価であるため世界中で広く利用され、産業上重要な位置を占める。このため生産量も非常に多く、世界の金属材料生産量の約95％は鋼となっている。 (Source: http://dbpedia.org/resource/Steel) |
