Properties of Iron & Steel
Very pure iron is prepared by reducing ferric oxide with hydrogen at 1,000 degrees C or by vacuum melting of a product obtained by electrolysis of ferrous ammonium sulphate solution. Chemically pure iron is produced by thermal decomposition of iron pentacarbonyl at 200 to 250 degree C, when iron is deposited as a fine powder.
Steel is manufactured by blending carbon and iron in a specified ratio, where the normal percentage of carbon ranging from 0.2 to 2.14 per cent of the total weight. Apart from carbon, the other alloying materials used in the production of steel include manganese, chromium, tungsten and vanadium.
Physical Properties of Iron
Pure iron is a grayish-white soft metal. Its melting point and boiling point are 1,528 degree C and 2,735 degree C respectively. Pure iron is malleable and ductile and does not harden on quenching. It is more magnetic than any other metal, and its magnetic properties remain unaffected even at a very high temperature. Iron is a good conductor of heat and electricity.
Physical Properties of Steel
The physical properties of steel do not resemble its component elements of carbon and iron. It is high in strength, low in weight, durable, flexible and corrosive resistant. It is highly flexible; hence it can be molded to any desired shape. One of the most important properties of steel is the ability to cool down quickly from a high temperature when exposed to water or oil. Unlike iron, steel does not rust very easily on exposure to water and moisture.
Allotropic Forms of Iron
Pure iron exists in three allotropic forms, depending on temperature. These are distinguished as α-, γ- and δ-iron respectively. These differ in their thermal stability, crystal structure, hardness, magnetic properties and in their ability to dissolve carbon.
α-iron or α-ferrite is stable below 768 degree C and the chief constituent of pure wrought iron i.e. wrought iron is the purest form of commercial iron containing 0.10 to 0.25 per cent of carbon. α-iron is soft and strongly magnetic.
γ-iron or γ---ferrite is stable between 906 degree C and 1404 degree C. Unlike α-iron, it is hard and non-magnetic.
δ-iron is stable below 1400 degree C. It is also non-magnetic in nature.
Steel Grades
Gradation of steel is carried out by many standard organizations depending on the physical properties and composition of the product. Hardness of the metal is the chief deciding factor, which differs based on the amount of carbon content. The higher the carbon content, the higher the hardness of the metal. However, a high quality steel always contain less carbon content along with less chances of fracture.
Chemical Properties of Iron
Pure iron is unaffected by dry air and pure water at ordinary temperature, but commercial iron rusts in moist air and water. Pure iron gives off hydrogen, nitrogen and carbon monoxide on heating. The metal burns brilliantly when heated in oxygen and also undergoes combustion in burning sulfur. It decomposes steam at red heat, which is utilized in the manufacture of hydrogen.
Tags: Properties Iron, Pure iron, carbon content, Iron Pure, Iron Pure iron, carbon content higher
