લોખંડ: આવૃત્તિઓ વચ્ચેનો તફાવત
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લીટી ૬:
# EN8
# WPS
'''ઊપયોગ:
ધાત્વિય(Metallurgical):'''
Iron production 2009 (million tonnes)[51] Country Iron ore Pig iron Direct iron Steel
ચીન(China) 1,114.9 549.4 573.6
ઓસ્ટ્રેલિયા(Australia) 393.9 4.4 5.2
બ્રાઝિલ(Brazil) 305.0 25.1 0.011 26.5
જાપાન(Japan) 66.9 87.5
ભારત(India) 257.4 38.2 23.4 63.5
રશિયા(Russia) 92.1 43.9 4.7 60.0
ઉક્રેઇન(Ukraine) 65.8 25.7 29.9
દ.કોરિયા(South Korea) 0.1 27.3 48.6
જર્મનિ(Germany) 0.4 20.1 0.38 32.7
વિશ્વ(World) 1,594.9 914.0 64.5 1,232.4
Iron is the most widely used of all the metals, accounting for 95% of worldwide metal production.[citation needed] Its low cost and high strength make it indispensable in engineering applications such as the construction of machinery and machine tools, automobiles, the hulls of large ships, and structural components for buildings. Since pure iron is quite soft, it is most commonly used in the form of steel.
Commercially available iron is classified based on purity and the abundance of additives. Pig iron has 3.5–4.5% carbon[52] and contains varying amounts of contaminants such as sulfur, silicon and phosphorus. Pig iron is not a saleable product, but rather an intermediate step in the production of cast iron and steel from iron ore. Cast iron contains 2–4% carbon, 1–6% silicon, and small amounts of manganese. Contaminants present in pig iron that negatively affect material properties, such as sulfur and phosphorus, have been reduced to an acceptable level. It has a melting point in the range of 1420–1470 K, which is lower than either of its two main components, and makes it the first product to be melted when carbon and iron are heated together. Its mechanical properties vary greatly, dependent upon the form carbon takes in the alloy.
"White" cast irons contain their carbon in the form of cementite, or iron carbide. This hard, brittle compound dominates the mechanical properties of white cast irons, rendering them hard, but unresistant to shock. The broken surface of a white cast iron is full of fine facets of the broken carbide, a very pale, silvery, shiny material, hence the appellation.
In gray iron the carbon exists free as fine flakes of graphite, and also renders the material brittle due to the stress-raising nature of the sharp edged flakes of graphite. A newer variant of gray iron, referred to as ductile iron is specially treated with trace amounts of magnesium to alter the shape of graphite to spheroids, or nodules, vastly increasing the toughness and strength of the material.
Wrought iron contains less than 0.25% carbon.[52] It is a tough, malleable product, but not as fusible as pig iron. If honed to an edge, it loses it quickly. Wrought iron is characterized by the presence of fine fibers of slag entrapped in the metal. Wrought iron is more corrosion resistant than steel. It has been almost completely replaced by mild steel for traditional "wrought iron" products and blacksmithing.
Mild steel corrodes more readily than wrought iron, but is cheaper and more widely available. Carbon steel contains 2.0% carbon or less,[53] with small amounts of manganese, sulfur, phosphorus, and silicon. Alloy steels contain varying amounts of carbon as well as other metals, such as chromium, vanadium, molybdenum, nickel, tungsten, etc. Their alloy content raises their cost, and so they are usually only employed for specialist uses. One common alloy steel, though, is stainless steel. Recent developments in ferrous metallurgy have produced a growing range of microalloyed steels, also termed 'HSLA' or high-strength, low alloy steels, containing tiny additions to produce high strengths and often spectacular toughness at minimal cost.
Photon mass attenuation coefficient for iron.Apart from traditional applications, iron is also used for protection from ionizing radiation. Although it is lighter than another traditional protection material, lead, it is much stronger mechanically. The attenuation of radiation as a function of energy is shown in the graph.
The main disadvantage of iron and steel is that pure iron, and most of its alloys, suffer badly from rust if not protected in some way. Painting, galvanization, passivation, plastic coating and bluing are all used to protect iron from rust by excluding water and oxygen
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