Steel

Steel is the name commonly given in metallurgical engineering from an alloy of iron with a variable amount of carbon between 0.1 and 2.1% by weight of composition, but typically these values ​​are between 0, 2% and 0.3%. If the alloy has a higher carbon concentration to 2.0% occur foundries, as opposed to steel, are brittle and it is possible to forge but must be molded. Not to be confused with iron steel, which is a relatively hard and tough metal with atomic diameter (dA) of 2.48 Å, with melting temperature of 1,535 ° C and boiling point 2740 ° C. In turn, carbon is a nonmetal smaller diameter (dA = 1.54 Å), soft and fragile in most of its allotropic forms (except diamond). The diffusion of this element in the crystal structure of the former is achieved by the difference in atomic diameters. 

The steel keeps the features of iron metal in its pure state, but the addition of carbon and other elements both metallic and nonmetallic improves their physical and chemical properties. There are many types of steel depending on the alloying elements or to be present. The definition in the percentage of carbon corresponds to carbon steels, where this is not the only alloying metal, or are there others but in lower concentrations. Other specific compositions are given specific names depending on many variables such as the elements that predominate in their composition (silicon steel), its susceptibility to certain treatments (hardened steel), some feature enhanced (stainless steel) and even depending on its use (structural steel). 

Usually these iron alloys are included under the generic designation of special steels, why here has adopted the definition of common or "carbon" in addition to being the first made and more employees, 1 formed the basis for others. This wide variety of steel was steel Siemens define as "an iron compound and another substance that increases resistance" .2 The two main components of steel are found in abundance in nature, favoring large-scale production. Disponibilidad3 this variety makes it suitable for many uses such as construction machinery, tools, buildings and public works, contributing to the technological development of societies industrializadas.4 Yet there are those who do not use steel (such as aircraft construction) because of its density (7850 kg / m³ density compared to the 2,700 kg / m³ of aluminum, for example) this is problem who do not use steel.