metal definition

They are those elements of the Periodic Table that present characteristics in common such as good electrical and thermal conductivity, whose binding forces are metallic bonds and which, in turn, have a tendency to lose electrons forming cations. In general, they are solid at room temperature.

Metal is the raw material of metallic materials. When metal is subjected to an industrial process, metallic materials for industrial use that have great applicability in our world are formed. In the first place, they are subjected to processes for their best use, on the other hand, many of these elements exist in the minerals of the rocks combined with other substances, so it is necessary to “clean” and “extract” them. To do this, they are subjected to physical and/or chemical changes.

These processes are known as metal casting, molding, cutting, machining, among others. In turn, they can also be subjected to industrial processes to obtain alloys, combinations of two or more elements that give the material certain characteristics depending on its composition.

Ferrous and non-ferrous metals

One of the best known and universally used is Iron. When the metallic compound contains iron it is called ferrous, on the other hand, when it does not have it, it is called non-ferrous, acting as a reference for the name.

Carbon steel is one of the most applicable iron and carbon based alloys, it is a ductile and malleable ferrous material, but it corrodes very easily. For this, many alloys add compounds that improve their corrosive character, such as Chromium, Nickel or even Lead.

In general, stainless steel is less corrodible and, in this case, it is also a ferrous metallic material. However, differences in composition (especially Chromium concentrations) give it greater resistance to corrosion.

As non-ferrous metallic elements, aluminum and copper are known. Aluminum, very useful, is a good thermal and electrical conductor, which is why they are used in wiring lines, as well as copper. The latter is reddish in color, unlike aluminum which has a characteristic whitish/silver color.

As in ferrous materials, alloys can also be formed, for example, brass is a famous alloy of copper and zinc, even bronze, derives from the conjunction of copper and tin.

Properties

In order to characterize them, we generally mention a series of properties that identify them and give them their uses. In the first place, we talk about the malleability of a metal and it is the ability to form thin sheets, when subjected to compression processes. The word “malleability” derives from the term “hammer”, which indicates that a material can change its shape and length without breaking or breaking it. In the industry, a well-known process is lamination, where sheets of the desired metal are obtained. Typically, a malleable material is aluminum, which is why we use aluminum foil in the kitchen, for example.

When we talk about ductility, in a metal it represents the ability to form threads, again when subjected to certain forces, without breaking. For example, copper is one of the most ductile metals.

The thermal and electrical conductivity are classic and highly studied properties of metals, which allows the flow of electrons through their own body or the flow of energy from their molecules to other bodies that are in contact respectively.

Another property of metals is mechanical resistance, and here we are talking about resistance to traction, compression, torsion and other forces. That is, when they are exposed to extreme loads, this property determines the degree to which they can withstand the load without breaking, it is a resistance to breakage produced either by a tensile force, a compression force, etc.

Brittleness is also usually indicated and has to do with the fact that it cannot experience plastic-type deformations. That is, when the elastic limit is exceeded, the material breaks.

This is how we also define the hardness of metals, in Rockwell degrees or, depending on the method, it can be Brinell or Vickers. The hardness indicates the degree of deformation that the metal experiences under a direct load.

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