Difference Between Metal and Steel

Metal vs Steel
 

Metals and steel are important for man, and they have been in use for a long period.

Metal

Metals are known to human kind for a very long time. There are evidences to prove about metal usage back in 6000 BC. Gold and copper were the first metals to be discovered. These were used to make tools, jewelry, statues, etc. Since then for a longer period only few other metals (17) were discovered. Now we are familiar with 86 different types of metals.

Metals are very important because of their unique characteristics. Usually metals are hard and strong (there are exceptions to this such as sodium. Sodium can be cut by a knife). Mercury is the metal which is in the liquid state. Besides mercury, all the other metals are found in the solid state, and it is hard to break them or change their shape compared to other nonmetal elements. Metals have a shiny appearance. Most metals have a silvery shine (except gold and copper). Since some metals are very reactive with the atmospheric gases like oxygen, they tend to get dull colors over time. This is mainly due to the formation of metal oxide layers. On the other hand, metals like gold and platinum are very stable and unreactive. Metals are Malleable and ductile, which allows them to be used for making certain tools.

Metals are atoms, which can form cations by removing electrons. So they are electropositive. The type of bond forms between metal atoms is called metallic bonding. Metals release electrons in their outer shells and these electrons are dispersed between metal cations. Therefore, they are known as a sea of delocalized electrons. The electrostatic interactions between the electrons and cations are called metallic bonding. The electrons can move; therefore, metals have the ability to conduct electricity. Also, they are good thermal conductors. Because of the metallic bonding, metals have an ordered structure. High melting points and boiling points of metals are also due to this strong metallic bonding. Moreover, metals have a higher density than water. Elements in group IA and IIA are light metals. They have some variations from the above described general features of metal.

Steel

Steel is an alloy made out of iron and carbon. The carbon percentage can vary depending on the grade and mostly it is between 0.2% and 2.1% by weight. Though carbon is the main alloying material for iron, some other elements like Tungsten, chromium, manganese can also be used for the purpose. Different types and amounts of alloying element used determine the hardness, ductility and tensile strength of steel. Alloying element is responsible for maintaining the crystal lattice structure of steel by preventing dislocation of iron atoms. Thus, it acts as the hardening agent in steel. The density of steel varies between 7,750 and 8,050 kg/m3 and this is affected by the alloying constituents too. Heat treatment is a process which changes the mechanical properties of steels. This will affect the ductility, hardness and electrical and thermal properties of steel.

There are different types of steel as carbon steel, mild steel, stainless steel, etc. Steel is mainly used for construction purposes. Buildings, stadiums, railway tracks, bridges are few places among many where steel is heavily used. Other than that, they are used in vehicles, ships, planes, machines, etc. Most of the daily used house appliances are also made by steel. Now most furniture is also replaced by steel products.